Merge branch 'rickard/port-optimizations/OTP-10336' into rickard/r16/port-optimizations/OTP-10336

* rickard/port-optimizations/OTP-10336:
  Change annotate level for emacs-22 in cerl
  Update etp-commands
  Add documentation on communication in Erlang
  Add support for busy port message queue
  Add driver callback epilogue
  Implement true asynchronous signaling between processes and ports
  Add erl_drv_[send|output]_term
  Move busy port flag
  Use rwlock for driver list
  Optimize management of port tasks
  Improve configuration of process and port tables
  Remove R9 compatibility features
  Use ptab functionality also for ports
  Prepare for use of ptab functionality also for ports
  Atomic port state
  Generalize process table implementation
  Implement functionality for delaying thread progress from unmanaged threads

Conflicts:
	erts/doc/src/erl_driver.xml
	erts/doc/src/erlang.xml
	erts/emulator/beam/beam_bif_load.c
	erts/emulator/beam/beam_bp.c
	erts/emulator/beam/beam_emu.c
	erts/emulator/beam/bif.c
	erts/emulator/beam/copy.c
	erts/emulator/beam/erl_alloc.c
	erts/emulator/beam/erl_alloc.types
	erts/emulator/beam/erl_bif_info.c
	erts/emulator/beam/erl_bif_port.c
	erts/emulator/beam/erl_bif_trace.c
	erts/emulator/beam/erl_init.c
	erts/emulator/beam/erl_message.c
	erts/emulator/beam/erl_port_task.c
	erts/emulator/beam/erl_process.c
	erts/emulator/beam/erl_process.h
	erts/emulator/beam/erl_process_lock.c
	erts/emulator/beam/erl_trace.c
	erts/emulator/beam/export.h
	erts/emulator/beam/global.h
	erts/emulator/beam/io.c
	erts/emulator/sys/unix/sys.c
	erts/emulator/sys/vxworks/sys.c
	erts/emulator/test/port_SUITE.erl
	erts/etc/unix/cerl.src
	erts/preloaded/ebin/erlang.beam
	erts/preloaded/ebin/prim_inet.beam
	erts/preloaded/src/prim_inet.erl
	lib/hipe/cerl/erl_bif_types.erl
	lib/kernel/doc/src/inet.xml
	lib/kernel/src/inet.erl

1 files changed, 3362 insertions, 1093 deletions

diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 60b9238d38..3fc124589b 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -43,6 +43,8 @@
 #include "erl_version.h"
 #include "error.h"
 #include "erl_async.h"
+#define ERTS_WANT_EXTERNAL_TAGS
+#include "external.h"
 #include "dtrace-wrapper.h"
 
 extern ErlDrvEntry fd_driver_entry;
@@ -51,25 +53,29 @@ extern ErlDrvEntry spawn_driver_entry;
 extern ErlDrvEntry *driver_tab[]; /* table of static drivers, only used during initialization */
 
 erts_driver_t *driver_list; /* List of all drivers, static and dynamic. */
-erts_smp_mtx_t erts_driver_list_lock; /* Mutex for driver list */
+erts_smp_rwmtx_t erts_driver_list_lock; /* Mutex for driver list */
 static erts_smp_tsd_key_t driver_list_lock_status_key; /*stop recursive locks when calling 
 							 driver init */
 static erts_smp_tsd_key_t driver_list_last_error_key;  /* Save last DDLL error on a 
 							  per thread basis (for BC interfaces) */
 
-Port*      erts_port; /* The port table */
+ErtsPTab erts_port erts_align_attribute(ERTS_CACHE_LINE_SIZE); /* The port table */
 erts_smp_atomic_t erts_bytes_out;	/* No bytes sent out of the system */
 erts_smp_atomic_t erts_bytes_in;	/* No bytes gotten into the system */
 
-Uint erts_max_ports;
-Uint erts_port_tab_index_mask;
-
 const ErlDrvTermData driver_term_nil = (ErlDrvTermData)NIL;
 
+const Port erts_invalid_port = {{ERTS_INVALID_PORT}};
+
 erts_driver_t vanilla_driver;
 erts_driver_t spawn_driver;
 erts_driver_t fd_driver;
 
+int erts_port_synchronous_ops = 0;
+int erts_port_schedule_all_ops = 0;
+int erts_port_parallelism = 0;
+
+static void deliver_result(Eterm sender, Eterm pid, Eterm res);
 static int init_driver(erts_driver_t *, ErlDrvEntry *, DE_Handle *);
 static void terminate_port(Port *p);
 static void pdl_init(void);
@@ -89,36 +95,12 @@ static void driver_monitor_unlock_pdl(Port *p);
 static ERTS_INLINE ErlIOQueue*
 drvport2ioq(ErlDrvPort drvport)
 {
-    int ix = (int) drvport;
-    Uint32 status;
-
-    if (ix < 0 || erts_max_ports <= ix)
+    Port *prt = erts_thr_drvport2port_raw(drvport);
+    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
 	return NULL;
-
-    if (erts_get_scheduler_data()) {
-	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(&erts_port[ix]));
-	ERTS_LC_ASSERT(!erts_port[ix].port_data_lock
-		       || erts_lc_mtx_is_locked(
-			   &erts_port[ix].port_data_lock->mtx));
-
-	status = erts_port[ix].status;
-    }
-    else {
-	erts_smp_port_state_lock(&erts_port[ix]);
-	status = erts_port[ix].status;
-	erts_smp_port_state_unlock(&erts_port[ix]);
-
-	ERTS_LC_ASSERT((status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
-		       || erts_port[ix].port_data_lock);
-	ERTS_LC_ASSERT(!erts_port[ix].port_data_lock
-		       || erts_lc_mtx_is_locked(
-			   &erts_port[ix].port_data_lock->mtx));
-
-    }
-
-    return ((status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
-	    ? NULL
-	    : &erts_port[ix].ioq);
+    else
+	return &prt->ioq;
 }
 
 static ERTS_INLINE int
@@ -196,27 +178,13 @@ typedef struct line_buf_context {
     dtrace_port_str((PORT), port_str);
 #endif
 
-/* The 'number' field in a port now has two parts: the lowest bits
-   contain the index in the port table, and the higher bits are a counter
-   which is incremented each time we look for a free port and start from
-   the beginning of the table. erts_max_ports is the number of file descriptors,
-   rounded up to a power of 2.
-   To get the index from a port, use the macro 'internal_port_index';
-   'port_number' returns the whole number field.
-*/
-
-static erts_smp_spinlock_t get_free_port_lck;
-static Uint last_port_num;
-static Uint port_num_mask;
-erts_smp_atomic32_t erts_ports_snapshot; /* Identifies the _next_ snapshot (not the ongoing) */
-
-
 static ERTS_INLINE void
 kill_port(Port *pp)
 {
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(pp));
+    erts_ptab_delete_element(&erts_port, &pp->common); /* Time of death */
     erts_port_task_free_port(pp);
-    ASSERT(pp->status & ERTS_PORT_SFLGS_DEAD);
+    /* In non-smp case the port structure may have been deallocated now */
 }
 
 #ifdef ERTS_SMP
@@ -227,146 +195,280 @@ erts_lc_is_port_locked(Port *prt)
 {
     if (!prt)
 	return 0;
+    ERTS_SMP_LC_ASSERT(prt->lock);
     return erts_smp_lc_mtx_is_locked(prt->lock);
 }
 #endif
 
 #endif /* #ifdef ERTS_SMP */
 
-static int
-get_free_port(void)
-{
-    Uint num;
-    Uint tries = erts_max_ports;
-    Port* port;    
+static void initq(Port* prt);
 
-    erts_smp_spin_lock(&get_free_port_lck);
-    num = last_port_num + 1;
-    for (;; ++num) {	
-	port = &erts_port[num & erts_port_tab_index_mask];
+#if defined(ERTS_ENABLE_LOCK_CHECK) || defined(ERTS_ENABLE_LOCK_COUNT)
+#define ERTS_PORT_INIT_INSTR_NEED_ID 1
+#else
+#define ERTS_PORT_INIT_INSTR_NEED_ID 0
+#endif
 
-	erts_smp_port_state_lock(port);
-	if (port->status & ERTS_PORT_SFLG_FREE) {
-	    last_port_num = num;
-	    erts_smp_spin_unlock(&get_free_port_lck);
-	    break;
-	}
-	erts_smp_port_state_unlock(port);
+static ERTS_INLINE void port_init_instr(Port *prt
+#if ERTS_PORT_INIT_INSTR_NEED_ID
+				   , Eterm id
+#endif
+    )
+{
+#if !ERTS_PORT_INIT_INSTR_NEED_ID
+    Eterm id = NIL; /* Not used */
+#endif
 
-	if (--tries == 0) {
-	    erts_smp_spin_unlock(&get_free_port_lck);
-	    return -1;
-	}
+    /*
+     * Stuff that need to be initialized with the port id
+     * in the instrumented case, but not in the normal case.
+     */
+#ifdef ERTS_SMP
+    ASSERT(prt->drv_ptr && prt->lock);
+    if (!prt->drv_ptr->lock) {
+	char *lock_str = "port_lock";
+#ifdef ERTS_ENABLE_LOCK_COUNT
+	if (!(erts_lcnt_rt_options & ERTS_LCNT_OPT_PORTLOCK))
+	    lock_str = NULL;
+#endif
+	erts_mtx_init_locked_x(prt->lock, lock_str, id);
     }
-    port->status = ERTS_PORT_SFLG_INITIALIZING;
-    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 0);
-    erts_smp_atomic_set_nob(&port->refc, 2); /* Port alive + lock */
-    erts_smp_port_state_unlock(port);
-    return num & port_num_mask;
+#endif
+    erts_port_task_init_sched(&prt->sched, id);
 }
 
-/*
- * erts_test_next_port() is only used for testing.
- */
-Sint
-erts_test_next_port(int set, Uint next)
+#if !ERTS_PORT_INIT_INSTR_NEED_ID
+static ERTS_INLINE void port_init_instr_abort(Port *prt)
 {
-    Uint i, num;
-    Sint res = -1;
-
-    erts_smp_spin_lock(&get_free_port_lck);
-    if (set) {
-	last_port_num = (next - 1) & port_num_mask;
+#ifdef ERTS_SMP
+    ASSERT(prt->drv_ptr && prt->lock);
+    if (!prt->drv_ptr->lock) {
+	erts_mtx_unlock(prt->lock);
+	erts_mtx_destroy(prt->lock);
     }
-    num = last_port_num + 1;
+#endif
+    erts_port_task_fini_sched(&prt->sched);
+}
+#endif
 
-    for (i=0; i < erts_max_ports && res<0; ++i, ++num) {	
-	
-	Port* port = &erts_port[num & erts_port_tab_index_mask];
+static void insert_port_struct(void *vprt, Eterm data)
+{
+    Port *prt = (Port *) vprt;
+    Eterm id = make_internal_port(data);
+#if ERTS_PORT_INIT_INSTR_NEED_ID
+    /*
+     * This cannot be done earlier in the instrumented
+     * case since we don't now 'id' until now.
+     */
+    port_init_instr(prt, id);
+#endif
+    prt->common.id = id;
+    erts_atomic32_init_relb(&prt->state, ERTS_PORT_SFLG_INITIALIZING);
+}
 
-	erts_smp_port_state_lock(port);
+#define ERTS_CREATE_PORT_FLAG_PARALLELISM		(1 << 0)
 
-	if (port->status & ERTS_PORT_SFLG_FREE) {	   
-	    last_port_num = num - 1;
-	    res = num & port_num_mask;
-	}
-	erts_smp_port_state_unlock(port);
+static Port *create_port(char *name,
+			 erts_driver_t *driver,
+			 erts_mtx_t *driver_lock,
+			 int create_flags,
+			 Eterm pid,
+			 int *enop)
+{
+    ErtsPortTaskBusyPortQ *busy_port_queue;
+    Port *prt;
+    char *p;
+    size_t port_size, busy_port_queue_size, size;
+    erts_aint32_t state = ERTS_PORT_SFLG_CONNECTED;
+    erts_aint32_t x_pts_flgs = 0;
+#ifdef DEBUG
+    /* Make sure the debug flags survives until port is freed */
+    state |= ERTS_PORT_SFLG_PORT_DEBUG;
+#endif
+
+#ifdef ERTS_SMP
+    if (!driver_lock) {
+	/* Align size for mutex following port struct */
+	port_size = size = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(Port));
+	size += sizeof(erts_mtx_t);
     }
-    erts_smp_spin_unlock(&get_free_port_lck);
-    return res;
-}
+    else
+#endif
+	port_size = size = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(Port));
 
+    busy_port_queue_size
+	= ((driver->flags & ERL_DRV_FLAG_NO_BUSY_MSGQ)
+	   ? 0
+	   : ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErtsPortTaskBusyPortQ)));
+    size += busy_port_queue_size;
 
-static void port_cleanup(Port *prt);
+    size += sys_strlen(name) + 1;
 
-#ifdef ERTS_SMP
+    p = erts_alloc_fnf(ERTS_ALC_T_PORT, size);
+    if (!p) {
+	if (enop)
+	    *enop = ENOMEM;
+	return NULL;
+    }
 
-static void
-sched_port_cleanup(void *vprt)
-{
-    Port *prt = (Port *) vprt;
-    erts_smp_mtx_lock(prt->lock);
-    port_cleanup(prt);
-}
+    prt = (Port *) p;
+    p += port_size;
 
-#endif
+    if (!busy_port_queue_size)
+	busy_port_queue = NULL;
+    else {
+	busy_port_queue = (ErtsPortTaskBusyPortQ *) p;
+	p += busy_port_queue_size;
+    }
 
-void
-erts_port_cleanup(Port *prt)
-{
 #ifdef ERTS_SMP
-    if (erts_smp_mtx_trylock(prt->lock) == EBUSY)
-	erts_schedule_misc_op(sched_port_cleanup, (void *) prt);
-    else
+    if (driver_lock) {
+	prt->lock = driver_lock;
+	erts_mtx_lock(driver_lock);
+    }
+    else {
+	prt->lock = (erts_mtx_t *) p;
+	p += sizeof(erts_mtx_t);
+	state |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
+    }
+    erts_smp_atomic_set_nob(&prt->run_queue,
+			    (erts_aint_t) erts_get_runq_current(NULL));
+    prt->xports = NULL;
+#else
+    erts_atomic32_init_nob(&prt->refc, 1);
+    prt->cleanup = 0;
 #endif
-	port_cleanup(prt);
-}
+    
+    erts_port_task_pre_init_sched(&prt->sched, busy_port_queue);
 
-void
-port_cleanup(Port *prt)
-{
+    prt->name = p;
+    sys_strcpy(p, name);
+    prt->drv_ptr = driver;
+    ERTS_P_LINKS(prt) = NULL;
+    ERTS_P_MONITORS(prt) = NULL;
+    prt->linebuf = NULL;
+    prt->bp = NULL;
+    prt->suspended = NULL;
+    prt->data = am_undefined;
+    prt->port_data_lock = NULL;
+    prt->control_flags = 0;
+    prt->bytes_in = 0;
+    prt->bytes_out = 0;
+    prt->dist_entry = NULL;
+    ERTS_PORT_INIT_CONNECTED(prt, pid);
+    prt->common.u.alive.reg = NULL;
 #ifdef ERTS_SMP
-    Uint32 port_specific;
-    erts_smp_mtx_t *mtx;
+    prt->common.u.alive.ptimer = NULL;
+#else
+    sys_memset(&prt->common.u.alive.tm, 0, sizeof(ErlTimer));
 #endif
-    erts_driver_t *driver;
+    erts_port_task_handle_init(&prt->timeout_task);
+    prt->psd = NULL;
+    prt->drv_data = (SWord) 0;
+    prt->os_pid = -1;
 
-    erts_smp_port_state_lock(prt);
+    /* Set default tracing */
+    erts_get_default_tracing(&ERTS_TRACE_FLAGS(prt), &ERTS_TRACER_PROC(prt));
 
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    driver = prt->drv_ptr;
-    prt->drv_ptr = NULL;
-    ASSERT(driver);
+    ASSERT(((char *) prt) == ((char *) &prt->common));
 
-    ASSERT(prt->status & ERTS_PORT_SFLG_FREE_SCHEDULED);
-    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&prt->refc) == 0);
+#if !ERTS_PORT_INIT_INSTR_NEED_ID
+    /*
+     * When 'id' isn't needed (the normal case), it is better to
+     * do the initialization here avoiding unnecessary contention
+     * on table...
+     */
+    port_init_instr(prt);
+#endif
 
-    ASSERT(prt->status & ERTS_PORT_SFLG_PORT_DEBUG);
-    ASSERT(!(prt->status & ERTS_PORT_SFLG_FREE));
-    prt->status = ERTS_PORT_SFLG_FREE;
+    if (!erts_ptab_new_element(&erts_port,
+			       &prt->common,
+			       (void *) prt,
+			       insert_port_struct)) {
 
+#if !ERTS_PORT_INIT_INSTR_NEED_ID
+	port_init_instr_abort(prt);
+#endif
 #ifdef ERTS_SMP
+	if (driver_lock)
+	    erts_mtx_unlock(driver_lock);
+#endif
+	if (enop)
+	    *enop = 0;
+	return NULL;
+    }
 
-    port_specific = (prt->status & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK);
+    ASSERT(prt == (Port *) (erts_ptab_pix2intptr_nob(
+				&erts_port,
+				internal_port_index(prt->common.id))));
 
-    mtx = prt->lock;
-    ASSERT(mtx);
+    initq(prt);
 
-    prt->lock = NULL;
+    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    erts_smp_port_state_unlock(prt);    
-    erts_smp_mtx_unlock(mtx);
+    if (erts_port_schedule_all_ops)
+	x_pts_flgs |= ERTS_PTS_FLG_FORCE_SCHED;
 
-    if (port_specific) {
-	erts_smp_mtx_destroy(mtx);
-	erts_free(ERTS_ALC_T_PORT_LOCK, mtx);
-    }
-#endif
+    if (create_flags & ERTS_CREATE_PORT_FLAG_PARALLELISM)
+	x_pts_flgs |= ERTS_PTS_FLG_PARALLELISM;
 
-    if (driver->handle)
-	erts_ddll_dereference_driver(driver->handle);
+    if (x_pts_flgs)
+	erts_smp_atomic32_read_bor_nob(&prt->sched.flags, x_pts_flgs);
+
+    erts_atomic32_set_relb(&prt->state, state);
+    return prt;
+}
+
+#ifndef ERTS_SMP
+void
+erts_port_cleanup(Port *prt)
+{
+    if (prt->drv_ptr && prt->drv_ptr->handle)
+	erts_ddll_dereference_driver(prt->drv_ptr->handle);
+    prt->drv_ptr = NULL;
+    erts_port_dec_refc(prt);
 }
+#endif
 
+void
+erts_port_free(Port *prt)
+{
+#if defined(ERTS_SMP) || defined(ERTS_ENABLE_LOCK_CHECK)
+    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);
+#endif
+    ERTS_LC_ASSERT(state & (ERTS_PORT_SFLG_INITIALIZING
+			    | ERTS_PORT_SFLG_FREE));
+    ASSERT(state & ERTS_PORT_SFLG_PORT_DEBUG);
+
+#ifdef ERTS_SMP
+    ERTS_LC_ASSERT(erts_atomic32_read_nob(&prt->common.refc) == 0);
+#else
+    ERTS_LC_ASSERT(erts_atomic32_read_nob(&prt->refc) == 0);
+#endif
+
+    erts_port_task_fini_sched(&prt->sched);
+
+#ifdef ERTS_SMP
+    ASSERT(prt->lock);
+    if (state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK)
+	erts_mtx_destroy(prt->lock);
+
+    /*
+     * We cannot dereference a driver using driver
+     * locking until here in smp case. Otherwise,
+     * the driver lock may still be in use by others.
+     *
+     * In the non-smp case we cannot do it here since
+     * this function may be called by non-scheduler
+     * threads. This is done in erts_port_cleanup()
+     * in the non-smp case.
+     */
+    if (prt->drv_ptr->handle)
+	erts_ddll_dereference_driver(prt->drv_ptr->handle);
+#endif
+    erts_free(ERTS_ALC_T_PORT, prt);
+}
 
 /*
 ** Initialize v_start to point to the small fixed vector.
@@ -414,94 +516,21 @@ static void stopq(Port* prt)
     if (prt->port_data_lock) {
 	driver_pdl_unlock(prt->port_data_lock);
 	driver_pdl_dec_refc(prt->port_data_lock);
-	prt->port_data_lock = NULL;
-    }
-}
-
-
-
-static void
-setup_port(Port* prt, Eterm pid, erts_driver_t *driver, 
-	   ErlDrvData drv_data, char *name, Uint32 xstatus)
-{
-    ErtsRunQueue *runq = erts_get_runq_current(NULL);
-    char *new_name, *old_name;
-#ifdef DEBUG
-    /* Make sure the debug flags survives until port is freed */
-    xstatus |= ERTS_PORT_SFLG_PORT_DEBUG;
-#endif
-    ASSERT(runq);
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-
-    
-    new_name = (char*) erts_alloc(ERTS_ALC_T_PORT_NAME, sys_strlen(name)+1);
-    sys_strcpy(new_name, name);
-    erts_smp_runq_lock(runq);
-    erts_smp_port_state_lock(prt);    
-    prt->os_pid = -1;
-    prt->status = ERTS_PORT_SFLG_CONNECTED | xstatus;
-    prt->snapshot = erts_smp_atomic32_read_nob(&erts_ports_snapshot);    
-    old_name = prt->name;
-    prt->name = new_name;
-#ifdef ERTS_SMP
-    erts_smp_atomic_set_nob(&prt->run_queue, (erts_aint_t) runq);
-#endif
-    ASSERT(!prt->drv_ptr);
-    prt->drv_ptr = driver;
-    erts_smp_port_state_unlock(prt);
-    erts_smp_runq_unlock(runq);
-#ifdef ERTS_SMP
-    ASSERT(!prt->xports);
-#endif
-    if (old_name) {
-	erts_free(ERTS_ALC_T_PORT_NAME, (void *) old_name);
     }
-
-    prt->control_flags = 0;
-    prt->connected = pid;
-    prt->drv_data = (SWord) drv_data;
-    prt->bytes_in = 0;
-    prt->bytes_out = 0;
-    prt->dist_entry = NULL;
-    prt->reg = NULL;
-#ifdef ERTS_SMP
-    prt->ptimer = NULL;
-#else
-    sys_memset(&prt->tm, 0, sizeof(ErlTimer));
-#endif
-    erts_port_task_handle_init(&prt->timeout_task);
-    prt->suspended  = NULL;
-    sys_strcpy(prt->name, name);
-    prt->nlinks = NULL;
-    prt->monitors = NULL;
-    prt->linebuf = NULL;
-    prt->bp = NULL;
-    prt->data = am_undefined;
-    /* Set default tracing */
-    erts_get_default_tracing(&(prt->trace_flags), &(prt->tracer_proc));
-
-    prt->psd = NULL;
-
-    initq(prt);
 }
 
-void
-erts_wake_process_later(Port *prt, Process *process)
+int
+erts_save_suspend_process_on_port(Port *prt, Process *process)
 {
-    ErtsProcList** p;
-    ErtsProcList* new_p;
-
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-
-    if (prt->status & ERTS_PORT_SFLGS_DEAD)
-	return;
-
-    for (p = &(prt->suspended); *p != NULL; p = &((*p)->next))
-	/* Empty loop body */;
-
-    new_p = erts_proclist_create(process);
-    new_p->next = NULL;
-    *p = new_p;
+    int saved;
+    erts_aint32_t flags;
+    erts_port_task_sched_lock(&prt->sched);
+    flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+    saved = (flags & ERTS_PTS_FLGS_BUSY) && !(flags & ERTS_PTS_FLG_EXIT);
+    if (saved)
+	erts_proclist_store_last(&prt->suspended, erts_proclist_create(process));
+    erts_port_task_sched_unlock(&prt->sched);
+    return saved;
 }
 
 /*
@@ -513,47 +542,44 @@ erts_wake_process_later(Port *prt, Process *process)
    (*error_number_ptr must contain either BADARG or SYSTEM_LIMIT).
    The driver start function must obey the same conventions.
 */
-int
+Port *
 erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
 		 Eterm pid,		/* Current process. */
 		 char* name,		/* Driver name. */
 		 SysDriverOpts* opts,	/* Options. */
-		 int *error_number_ptr)	/* errno in case -2 is returned */
+		 int *error_type_ptr,	/* error type */
+		 int *error_number_ptr)	/* errno in case of error type -2 */
 {
-    int port_num;
-    int port_ix;
+
+#undef ERTS_OPEN_DRIVER_RET
+#define ERTS_OPEN_DRIVER_RET(Prt, EType, ENo)	\
+    do {					\
+	if (error_type_ptr)			\
+	    *error_type_ptr = (EType);		\
+	if (error_number_ptr)			\
+	    *error_number_ptr = (ENo);		\
+	return (Prt);				\
+    } while (0)
+
     ErlDrvData drv_data = 0;
-    Uint32 xstatus = 0;
     Port *port;
     int fpe_was_unmasked;
-
-    if (error_number_ptr)
-	*error_number_ptr = 0;
+    int error_type, error_number;
+    int port_errno = 0;
+    erts_mtx_t *driver_lock = NULL;
+    int cprt_flgs = 0;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    if ((port_num = get_free_port()) < 0) {
-	if (error_number_ptr) {
-	    *error_number_ptr = SYSTEM_LIMIT;
-	}
-	return -3;
-    }
-
-    port_ix = port_num & erts_port_tab_index_mask;
-    port = &erts_port[port_ix];
-    port->id = make_internal_port(port_num);
-
-    erts_smp_mtx_lock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
     if (!driver) {
 	for (driver = driver_list; driver; driver = driver->next) {
 	    if (sys_strcmp(driver->name, name) == 0)
 		break;
 	}
 	if (!driver) { 
-	    erts_smp_mtx_unlock(&erts_driver_list_lock);
-	    if (error_number_ptr)
-		*error_number_ptr = BADARG;
-	    return -3;
+	    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	    ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
 	}
     }
     if (driver == &spawn_driver) {
@@ -597,59 +623,49 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
     }
 
     if (driver == NULL || (driver != &spawn_driver && opts->exit_status)) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
-	if (error_number_ptr) {
-	    *error_number_ptr = BADARG;
-	}
-	/* Need to mark the port as free again */
-	erts_smp_port_state_lock(port);
-	port->status = ERTS_PORT_SFLG_FREE;
-	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 2);
-	erts_smp_atomic_set_nob(&port->refc, 0); 
-	erts_smp_port_state_unlock(port);
-	return -3;
+	erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	ERTS_OPEN_DRIVER_RET(NULL, -3, BADARG);
     }
 
-    /*
-     * We'll set up the port before calling the start function,
-     * to allow message sending and setting timers in the start function.
-     */
-
 #ifdef ERTS_SMP
-    ASSERT(!port->lock);
-    port->lock = driver->lock;
-    if (!port->lock) {
-	port->lock = erts_alloc(ERTS_ALC_T_PORT_LOCK,
-					      sizeof(erts_smp_mtx_t));
-	erts_smp_mtx_init_x(port->lock,
-#ifdef ERTS_ENABLE_LOCK_COUNT
-			    (erts_lcnt_rt_options & ERTS_LCNT_OPT_PORTLOCK) ? "port_lock" : NULL,
-#else
-			    "port_lock",
-#endif
-			    port->id);
-	xstatus |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
-    }
+    driver_lock = driver->lock;
 #endif
 
     if (driver->handle != NULL) {
 	erts_ddll_increment_port_count(driver->handle);
 	erts_ddll_reference_driver(driver->handle);
     }
-    erts_smp_mtx_unlock(&erts_driver_list_lock);
+    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
 
-#ifdef ERTS_SMP
-    erts_smp_mtx_lock(port->lock);
-#endif
+    /*
+     * We'll set up the port before calling the start function,
+     * to allow message sending and setting timers in the start function.
+     */
+
+    if (opts->parallelism)
+	cprt_flgs |= ERTS_CREATE_PORT_FLAG_PARALLELISM;
 
-    setup_port(port, pid, driver, drv_data, name, xstatus);
+    port = create_port(name, driver, driver_lock, cprt_flgs, pid, &port_errno);
+    if (!port) {
+	if (driver->handle) {
+	    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
+	    erts_ddll_decrement_port_count(driver->handle);
+	    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	    erts_ddll_dereference_driver(driver->handle);
+	}
+	if (port_errno)
+	    ERTS_OPEN_DRIVER_RET(NULL, -2, port_errno);
+	else
+	    ERTS_OPEN_DRIVER_RET(NULL, -3, SYSTEM_LIMIT);
+    }
     
     if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
 	trace_port_open(port,
 		pid,		
 		am_atom_put(port->name, strlen(port->name)));
     }
-    
+
+    error_number = error_type = 0;
     if (driver->start) {
 	if (IS_TRACED_FL(port, F_TRACE_SCHED_PORTS)) {
 	    trace_sched_ports_where(port, am_in, am_start);
@@ -662,56 +678,63 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
         }
 #endif
 	fpe_was_unmasked = erts_block_fpe();
-	drv_data = (*driver->start)((ErlDrvPort)(port_ix),
-				    name, opts);
+	drv_data = (*driver->start)((ErlDrvPort) port, name, opts);
+	if (((SWord) drv_data) == -1)
+	    error_type = -1;
+	else if (((SWord) drv_data) == -2) {
+	    /*
+	     * We need to save errno quickly after the
+	     * call to the 'start' callback before
+	     * something else modify it.
+	     */
+	    error_type = -2;
+	    error_number = errno;
+	}
+	else if (((SWord) drv_data) == -3) {
+	    error_type = -3;
+	    error_number = BADARG;
+	}
+
 	erts_unblock_fpe(fpe_was_unmasked);
 	port->caller = NIL;
 	if (IS_TRACED_FL(port, F_TRACE_SCHED_PORTS)) {
 	    trace_sched_ports_where(port, am_out, am_start);
 	}
-	if (error_number_ptr && ((SWord) drv_data) == (SWord) -2)
-	    *error_number_ptr = errno;
 #ifdef ERTS_SMP
 	if (port->xports)
-	    erts_smp_xports_unlock(port);
+	    erts_port_handle_xports(port);
 	ASSERT(!port->xports);
 #endif
     }
 
-    if (((SWord)drv_data) == -1 || 
-	((SWord)drv_data) == -2 || 
-	((SWord)drv_data) == -3) {
-	int res = (int) ((SWord) drv_data);
-
-	if (res == -3 && error_number_ptr) {
-	    *error_number_ptr = BADARG;
-	}
-
+    if (error_type) {
 	/*
 	 * Must clean up the port.
 	 */
 #ifdef ERTS_SMP
-	erts_cancel_smp_ptimer(port->ptimer);
+	erts_cancel_smp_ptimer(port->common.u.alive.ptimer);
 #else
-	erts_cancel_timer(&(port->tm));
+	erts_cancel_timer(&(port->common.u.alive.tm));
 #endif
 	stopq(port);
-	kill_port(port);
 	if (port->linebuf != NULL) {
 	    erts_free(ERTS_ALC_T_LINEBUF,
 		      (void *) port->linebuf);
 	    port->linebuf = NULL;
 	}
 	if (driver->handle != NULL) {
-	    erts_smp_mtx_lock(&erts_driver_list_lock);
+	    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
 	    erts_ddll_decrement_port_count(driver->handle);
-	    erts_smp_mtx_unlock(&erts_driver_list_lock);
+	    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
 	}
+	kill_port(port);
 	erts_port_release(port);
-	return res;
+	ERTS_OPEN_DRIVER_RET(NULL, error_type, error_number);
     }
-    port->drv_data = (SWord) drv_data;
-    return port_ix;
+    port->drv_data = (UWord) drv_data;
+    ERTS_OPEN_DRIVER_RET(port, 0, 0);
+
+#undef ERTS_OPEN_DRIVER_RET
 }
 
 #ifdef ERTS_SMP
@@ -736,102 +759,122 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
 		   char* name,            /* Driver name */
 		   ErlDrvData drv_data)   /* Driver data */
 {
+    int cprt_flgs = 0;
     Port *creator_port;
     Port* port;
     erts_driver_t *driver;
     Process *rp;
-    int port_num;
-    Eterm port_id;
-    Uint32 xstatus = 0;
+    erts_mtx_t *driver_lock = NULL;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    creator_port = erts_drvport2port(creator_port_ix);
+    /* Need to be called from a scheduler thread */
+    if (!erts_get_scheduler_id())
+	return ERTS_INVALID_ERL_DRV_PORT;
+
+    creator_port = erts_drvport2port(creator_port_ix, NULL);
     if (!creator_port)
-	return (ErlDrvTermData) -1;
+	return ERTS_INVALID_ERL_DRV_PORT;
+
+    rp = erts_proc_lookup(pid);
+    if (!rp)
+	return ERTS_INVALID_ERL_DRV_PORT;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(creator_port));
 
     driver = creator_port->drv_ptr;
-    erts_smp_mtx_lock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
     if (!erts_ddll_driver_ok(driver->handle)) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
-	return (ErlDrvTermData) -1;
+	erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	return ERTS_INVALID_ERL_DRV_PORT;
     }
 
-    rp = erts_pid2proc(NULL, 0, pid, ERTS_PROC_LOCK_LINK);
-    if (!rp) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
-	return (ErlDrvTermData) -1;   /* pid does not exist */
+    if (driver->handle != NULL) {
+	erts_ddll_increment_port_count(driver->handle);
+	erts_ddll_reference_referenced_driver(driver->handle);
+    }
+
+#ifdef ERTS_SMP
+    driver_lock = driver->lock;
+#endif
+
+    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+
+    /* Inherit parallelism flag from parent */
+    if (ERTS_PTS_FLG_PARALLELISM &
+	erts_smp_atomic32_read_nob(&creator_port->sched.flags))
+	cprt_flgs |= ERTS_CREATE_PORT_FLAG_PARALLELISM;
+    port = create_port(name, driver, driver_lock, cprt_flgs, pid, NULL);
+    if (!port) {
+	if (driver->handle) {
+	    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
+	    erts_ddll_decrement_port_count(driver->handle);
+	    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	    erts_ddll_dereference_driver(driver->handle);
+	}
+	return ERTS_INVALID_ERL_DRV_PORT;
     }
-    if ((port_num = get_free_port()) < 0) {
-	errno = SYSTEM_LIMIT;
+    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(port));
+
+    erts_smp_proc_lock(rp, ERTS_PROC_LOCK_LINK);
+    if (ERTS_PROC_IS_EXITING(rp)) {
 	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
-	return (ErlDrvTermData) -1;
+	if (driver->handle) {
+	    erts_smp_rwmtx_rlock(&erts_driver_list_lock);
+	    erts_ddll_decrement_port_count(driver->handle);
+	    erts_smp_rwmtx_runlock(&erts_driver_list_lock);
+	}
+	kill_port(port);
+	erts_port_release(port);
+	return ERTS_INVALID_ERL_DRV_PORT;
     }
 
-    port_id = make_internal_port(port_num);
-    port = &erts_port[port_num & erts_port_tab_index_mask];
+    erts_add_link(&ERTS_P_LINKS(port), LINK_PID, pid);
+    erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, port->common.id);
+    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
 
 #ifdef ERTS_SMP
-    ASSERT(!port->lock);
-    port->lock = driver->lock;
-    if (!port->lock) {
+    if (!driver_lock) {
 	ErtsXPortsList *xplp = xports_list_alloc();
 	xplp->port = port;
 	xplp->next = creator_port->xports;
 	creator_port->xports = xplp;
-	port->lock = erts_alloc(ERTS_ALC_T_PORT_LOCK,
-					      sizeof(erts_smp_mtx_t));
-	erts_smp_mtx_init_locked_x(port->lock,
-#ifdef ERTS_ENABLE_LOCK_COUNT
-				   (erts_lcnt_rt_options & ERTS_LCNT_OPT_PORTLOCK) ? "port_lock" : NULL,
-#else
-				   "port_lock",
-#endif
-				   port_id);
-	xstatus |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
     }
-
 #endif
 
-    if (driver->handle != NULL) {
-	erts_ddll_increment_port_count(driver->handle);
-	erts_ddll_reference_referenced_driver(driver->handle);
-    }
-    erts_smp_mtx_unlock(&erts_driver_list_lock);
-
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(port));
+    port->drv_data = (UWord) drv_data;
 
-    setup_port(port, pid, driver, drv_data, name, xstatus);
-    port->id = port_id;
-
-    erts_add_link(&(port->nlinks), LINK_PID, pid);
-    erts_add_link(&(rp->nlinks), LINK_PID, port_id);
-    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
-    return port_num & erts_port_tab_index_mask;
+    return (ErlDrvPort) port;
 }
 
 #ifdef ERTS_SMP
-void
-erts_smp_xports_unlock(Port *prt)
+int erts_port_handle_xports(Port *prt)
 {
+    int reds = 0;
     ErtsXPortsList *xplp;
 
     ASSERT(prt);
     xplp = prt->xports;
     ASSERT(xplp);
     while (xplp) {
+	Port *rprt = xplp->port;
 	ErtsXPortsList *free_xplp;
-	if (xplp->port->xports)
-	    erts_smp_xports_unlock(xplp->port);
-	erts_port_release(xplp->port);
+	erts_aint32_t state;
+	if (rprt->xports)
+	    reds += erts_port_handle_xports(rprt);
+	state = erts_atomic32_read_nob(&rprt->state);
+	if ((state & ERTS_PORT_SFLG_CLOSING) && erts_is_port_ioq_empty(rprt)) {
+	    terminate_port(rprt);
+	    reds += ERTS_PORT_REDS_TERMINATE;
+	}
+	erts_port_release(rprt);
 	free_xplp = xplp;
 	xplp = xplp->next;
 	xports_list_free(free_xplp);
+	reds++;
     }
     prt->xports = NULL;
+    return reds;
 }
 #endif
 
@@ -866,8 +909,8 @@ io_list_to_vec(Eterm obj,	/* io-list */
     DECLARE_ESTACK(s);
     Eterm* objp;
     char *buf  = cbin->orig_bytes;
-    ErlDrvSizeT len = cbin->orig_size;
-    ErlDrvSizeT csize  = 0;
+    Uint len = cbin->orig_size;
+    Uint csize  = 0;
     int vlen   = 0;
     char* cptr = buf;
 
@@ -982,7 +1025,7 @@ io_list_to_vec(Eterm obj,	/* io-list */
 
 #define IO_LIST_VEC_COUNT(obj)						\
 do {									\
-    ErlDrvSizeT _size = binary_size(obj);				\
+    Uint _size = binary_size(obj);					\
     Eterm _real;							\
     ERTS_DECLARE_DUMMY(Uint _offset);					\
     int _bitoffs;							\
@@ -1033,8 +1076,9 @@ do {									\
  */
 
 static int 
-io_list_vec_len(Eterm obj, Uint* vsize, Uint* csize,
-		Uint* pvsize, Uint* pcsize, Uint* total_size)
+io_list_vec_len(Eterm obj, int* vsize, Uint* csize,
+		Uint* pvsize, Uint* pcsize,
+		ErlDrvSizeT* total_size)
 {
     DECLARE_ESTACK(s);
     Eterm* objp;
@@ -1045,7 +1089,7 @@ io_list_vec_len(Eterm obj, Uint* vsize, Uint* csize,
     Uint p_v_size = 0;
     Uint p_c_size = 0;
     Uint p_in_clist = 0;
-    Uint total;
+    Uint total; /* Uint due to halfword emulator */
 
     goto L_jump_start;  /* avoid a push */
 
@@ -1105,7 +1149,7 @@ io_list_vec_len(Eterm obj, Uint* vsize, Uint* csize,
     if (total < c_size) {
 	goto L_overflow_error;
     }
-    *total_size = total;
+    *total_size = (ErlDrvSizeT) total;
 
     DESTROY_ESTACK(s);
     *vsize = v_size;
@@ -1120,56 +1164,724 @@ io_list_vec_len(Eterm obj, Uint* vsize, Uint* csize,
     return 1;
 }
 
-/* write data to a port */
-int erts_write_to_port(Eterm caller_id, Port *p, Eterm list)
-{
-    char *buf;
-    erts_driver_t *drv = p->drv_ptr;
-    Uint size;
+typedef enum {
+    ERTS_TRY_IMM_DRV_CALL_OK,
+    ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK,
+    ERTS_TRY_IMM_DRV_CALL_INVALID_PORT,
+    ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS
+} ErtsTryImmDrvCallResult;
+
+typedef struct {
+    Process *c_p; /* Currently executing process (unlocked) */
+    Port *port; /* Port to operate on */
+    Eterm port_op; /* port operation as an atom */
+    erts_aint32_t state; /* in: invalid state; out: read state (if read) */
+    erts_aint32_t sched_flags; /* in: invalid flags; out: read flags (if read) */
+    int async; /* Asynchronous operation */
+    int pre_chk_sched_flags; /* Check sched flags before lock? */
     int fpe_was_unmasked;
-    
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p) || ERTS_IS_CRASH_DUMPING);
+} ErtsTryImmDrvCallState;
+
+#define ERTS_INIT_TRY_IMM_DRV_CALL_STATE(C_P, PRT, SFLGS, PTS_FLGS, A, PRT_OP) \
+    {(C_P), (PRT), (PRT_OP), (SFLGS), (PTS_FLGS), (A), 1, 0}
+
+/*
+ * Try doing an immediate driver callback call from a process. If
+ * this fail, the operation should be scheduled in the normal case...
+ *
+ */
+static ERTS_INLINE ErtsTryImmDrvCallResult
+try_imm_drv_call(ErtsTryImmDrvCallState *sp)
+{
+    ErtsTryImmDrvCallResult res;
+    erts_aint32_t invalid_state, invalid_sched_flags;
+    Port *prt = sp->port;
+    Process *c_p = sp->c_p;
+
+    ASSERT(is_atom(sp->port_op));
+
+    invalid_sched_flags = ERTS_PTS_FLGS_FORCE_SCHEDULE_OP;
+    invalid_sched_flags |= sp->sched_flags;
+    if (sp->async)
+	invalid_sched_flags |= ERTS_PTS_FLG_PARALLELISM;
+
+    if (sp->pre_chk_sched_flags) {
+	sp->sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+	if (sp->sched_flags & invalid_sched_flags)
+	    return ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS;
+    }
+
+    if (erts_smp_port_trylock(prt) == EBUSY)
+	return ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK;
+
+    invalid_state = sp->state;
+    sp->state = erts_atomic32_read_nob(&prt->state);
+    if (sp->state & invalid_state) {
+	res = ERTS_TRY_IMM_DRV_CALL_INVALID_PORT;
+	goto locked_fail;
+    }
+
+    sp->sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+    if (sp->sched_flags & invalid_sched_flags) {
+	res = ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS;
+	goto locked_fail;
+    }
+
+    if (c_p) {
+	if (IS_TRACED_FL(c_p, F_TRACE_SCHED_PROCS))
+	    trace_virtual_sched(c_p, am_out);
+	if (erts_system_profile_flags.runnable_procs
+	    && erts_system_profile_flags.exclusive)
+	    profile_runnable_proc(c_p, am_inactive);
+
+	erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+    }
+
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    p->caller = caller_id;
-    if (drv->outputv != NULL) {
-	Uint vsize;
-	Uint csize;
-	Uint pvsize;
-	Uint pcsize;
-	ErlDrvSizeT blimit;
+    if (IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS))
+	trace_sched_ports_where(prt, am_in, sp->port_op);
+    if (erts_system_profile_flags.runnable_ports
+	&& !erts_port_is_scheduled(prt))
+    	profile_runnable_port(prt, am_active);
+
+    sp->fpe_was_unmasked = erts_block_fpe();
+
+    return ERTS_TRY_IMM_DRV_CALL_OK;
+
+locked_fail:
+    erts_port_release(prt);
+    return res;
+}
+
+static ERTS_INLINE void
+finalize_imm_drv_call(ErtsTryImmDrvCallState *sp)
+{
+    Port *prt = sp->port;
+    Process *c_p = sp->c_p;
+
+    erts_port_driver_callback_epilogue(prt, NULL);
+
+    erts_unblock_fpe(sp->fpe_was_unmasked);
+
+    if (IS_TRACED_FL(prt, F_TRACE_SCHED_PORTS))
+	trace_sched_ports_where(prt, am_out, sp->port_op);
+    if (erts_system_profile_flags.runnable_ports
+	&& !erts_port_is_scheduled(prt))
+    	profile_runnable_port(prt, am_inactive);
+
+    erts_port_release(prt);
+
+    if (c_p) {
+	erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
+
+	if (IS_TRACED_FL(c_p, F_TRACE_SCHED_PROCS))
+	    trace_virtual_sched(c_p, am_in);
+	if (erts_system_profile_flags.runnable_procs
+	    && erts_system_profile_flags.exclusive)
+	    profile_runnable_proc(c_p, am_active);
+    }
+}
+
+/*
+ * force_imm_drv_call()/finalize_force_imm_drv_call() should *only*
+ * be used while crash dumping...
+ */
+static ErtsTryImmDrvCallResult
+force_imm_drv_call(ErtsTryImmDrvCallState *sp)
+{
+    erts_aint32_t invalid_state;
+    Port *prt = sp->port;
+
+    ASSERT(ERTS_IS_CRASH_DUMPING)
+    ASSERT(is_atom(sp->port_op));
+
+    invalid_state = sp->state;
+    sp->state = erts_atomic32_read_nob(&prt->state);
+    if (sp->state & invalid_state)
+	return ERTS_TRY_IMM_DRV_CALL_INVALID_PORT;
+
+    sp->fpe_was_unmasked = erts_block_fpe();
+
+    return ERTS_TRY_IMM_DRV_CALL_OK;
+}
+
+static void
+finalize_force_imm_drv_call(ErtsTryImmDrvCallState *sp)
+{
+    erts_unblock_fpe(sp->fpe_was_unmasked);
+}
+
+#define ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE (REF_THING_SIZE + 3)
+
+static ERTS_INLINE void
+queue_port_sched_op_reply(Process *rp,
+			  ErtsProcLocks *rp_locksp,
+			  Eterm *hp_start,
+			  Eterm *hp,
+			  Uint h_size,
+			  ErlHeapFragment* bp,
+			  Uint32 *ref_num,
+			  Eterm msg)
+{
+    Eterm ref = make_internal_ref(hp);
+    write_ref_thing(hp, ref_num[0], ref_num[1], ref_num[2]);
+    hp += REF_THING_SIZE;
+
+    msg = TUPLE2(hp, ref, msg);
+    hp += 3;
+
+    if (!bp) {
+	HRelease(rp, hp_start + h_size, hp);
+    }
+    else {
+	Uint used_h_size = hp - hp_start;
+	ASSERT(h_size >= used_h_size);
+	if (h_size > used_h_size)
+	    bp = erts_resize_message_buffer(bp, used_h_size, &msg, 1);
+    }
+
+    erts_queue_message(rp,
+		       rp_locksp,
+		       bp,
+		       msg,
+		       NIL
+#ifdef USE_VM_PROBES
+		       , NIL
+#endif
+	);
+}
+
+static void
+port_sched_op_reply(Eterm to, Uint32 *ref_num, Eterm msg)
+{
+    Process *rp = erts_proc_lookup_raw(to);
+    if (rp) {
+	ErlOffHeap *ohp;
+	ErlHeapFragment* bp;
+	Eterm msg_copy;
+	Uint hsz, msg_sz;
+	Eterm *hp, *hp_start;
+	ErtsProcLocks rp_locks = 0;
+
+	hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
+	if (is_immed(msg))
+	    msg_sz = 0;
+	else {
+	    msg_sz = size_object(msg);
+	    hsz += msg_sz;
+	}
+
+	hp_start = hp = erts_alloc_message_heap(hsz,
+						&bp,
+						&ohp,
+						rp,
+						&rp_locks);
+	if (is_immed(msg))
+	    msg_copy = msg;
+	else
+	    msg_copy = copy_struct(msg, msg_sz, &hp, ohp);
+
+	queue_port_sched_op_reply(rp,
+				  &rp_locks,
+				  hp_start,
+				  hp,
+				  hsz,
+				  bp,
+				  ref_num,
+				  msg_copy);
+
+	if (rp_locks)
+	    erts_smp_proc_unlock(rp, rp_locks);
+    }
+}
+
+
+ErtsPortOpResult
+erts_schedule_proc2port_signal(Process *c_p,
+			       Port *prt,
+			       Eterm caller,
+			       Eterm *refp,
+			       ErtsProc2PortSigData *sigdp,
+			       int task_flags,
+			       ErtsProc2PortSigCallback callback)
+{
+    int sched_res;
+    if (!refp) {
+	if (c_p)
+	    erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+    }
+    else {
+	ASSERT(c_p);
+	sigdp->flags |= ERTS_P2P_SIG_DATA_FLG_REPLY;
+	erts_make_ref_in_array(sigdp->ref);
+	*refp = erts_proc_store_ref(c_p, sigdp->ref);
+
+	/*
+	 * Caller needs to wait for a message containing
+	 * the ref that we just created. No such message
+	 * can exist in callers message queue at this time.
+	 * We therefore move the save pointer of the
+	 * callers message queue to the end of the queue.
+	 *
+	 * NOTE: It is of vital importance that the caller
+	 *       immediately do a receive unconditionaly
+	 *       waiting for the message with the reference;
+	 *       otherwise, next receive will *not* work
+	 *       as expected!
+	 */
+	erts_smp_proc_lock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+
+	if (ERTS_PROC_PENDING_EXIT(c_p)) {
+	    /* need to exit caller instead */
+	    erts_smp_proc_unlock(c_p, ERTS_PROC_LOCKS_MSG_RECEIVE);
+	    KILL_CATCHES(c_p);
+	    c_p->freason = EXC_EXIT;
+	    return ERTS_PORT_OP_CALLER_EXIT;
+	}
+
+	ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p);
+	c_p->msg.save = c_p->msg.last;
+
+	erts_smp_proc_unlock(c_p,
+			     (ERTS_PROC_LOCK_MAIN
+			      | ERTS_PROC_LOCKS_MSG_RECEIVE));
+    }
+
+
+    sigdp->caller = caller;
+
+    /* Schedule port close call for later execution... */
+    sched_res = erts_port_task_schedule(prt->common.id,
+					NULL,
+					ERTS_PORT_TASK_PROC_SIG,
+					sigdp,
+					callback,
+					task_flags);
+
+    if (c_p)
+	erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
+
+    if (sched_res != 0) {
+	if (refp)
+	    *refp = NIL;
+	return ERTS_PORT_OP_DROPPED;
+    }
+    return ERTS_PORT_OP_SCHEDULED;
+}
+
+static ERTS_INLINE void
+send_badsig(Port *prt)
+{
+    ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
+    Process* rp;
+    Eterm connected = ERTS_PORT_GET_CONNECTED(prt);
+
+    ERTS_SMP_CHK_NO_PROC_LOCKS;
+    ERTS_LC_ASSERT(erts_get_scheduler_id());
+
+    ASSERT(is_internal_pid(connected));
+
+    rp = erts_proc_lookup_raw(connected);
+    if (rp) {
+	erts_smp_proc_lock(rp, rp_locks);
+	if (!ERTS_PROC_IS_EXITING(rp))
+	    (void) erts_send_exit_signal(NULL,
+					 prt->common.id,
+					 rp,
+					 &rp_locks, 
+					 am_badsig,
+					 NIL,
+					 NULL,
+					 0);
+	if (rp_locks)
+	    erts_smp_proc_unlock(rp, rp_locks);
+    }
+}
+
+static void
+badsig_received(int bang_op,
+		Port *prt,
+		erts_aint32_t state,
+		int bad_output_value)
+{
+    /*
+     * if (bang_op)
+     *   we are part of a "Prt ! Something" operation
+     * else
+     *   we are part of a call to a port BIF
+     * behave accordingly...
+     */
+    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP)) {
+	if (bad_output_value) {
+	    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+	    erts_dsprintf(dsbufp, "Bad value on output port '%s'\n", prt->name);
+	    erts_send_error_to_logger_nogl(dsbufp);
+	}
+	if (bang_op)
+	    send_badsig(prt);
+    }
+}
+
+static int
+port_badsig(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    if (op == ERTS_PROC2PORT_SIG_EXEC)
+	badsig_received(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
+			prt,
+			state,
+			sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BAD_OUTPUT);
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg);
+    return ERTS_PORT_REDS_BADSIG;
+}
+
+
+/*
+ * bad_port_signal() will
+ * - preserve signal order of signals.
+ * - send a 'badsig' exit signal to connected process if 'from' is an
+ *   internal pid and the port is alive when the bad signal reaches
+ *   it.
+ */
+static ErtsPortOpResult
+bad_port_signal(Process *c_p,
+		int flags,
+		Port *prt,
+		Eterm from,
+		Eterm *refp,
+		Eterm port_op)
+{
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallResult try_call_res;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+	    c_p,
+	    prt,
+	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+	    0,
+	    !refp,
+	    port_op);
+
+    try_call_res = try_imm_drv_call(&try_call_state);
+    switch (try_call_res) {
+    case ERTS_TRY_IMM_DRV_CALL_OK:
+	badsig_received(flags & ERTS_PORT_SIG_FLG_BANG_OP,
+			prt,
+			try_call_state.state,
+			flags & ERTS_PORT_SIG_FLG_BAD_OUTPUT);
+	finalize_imm_drv_call(&try_call_state);
+	return ERTS_PORT_OP_BADARG;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+	/* Schedule badsig() call instead... */
+	break;
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = (flags & ~ERTS_P2P_SIG_TYPE_MASK) | ERTS_P2P_SIG_TYPE_BAD;
+
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p->common.id,
+					  refp,
+					  sigdp,
+					  0,
+					  port_badsig);
+}
+
+
+/*
+ * Driver outputv() callback
+ */
+
+static ERTS_INLINE void
+call_driver_outputv(int bang_op,
+		    Eterm caller,
+		    Eterm from,
+		    Port *prt,
+		    erts_driver_t *drv,
+		    ErlIOVec *evp)
+{
+    /*
+     * if (bang_op)
+     *   we are part of a "Prt ! {From, {command, Data}}" operation
+     * else
+     *   we are part of a call to port_command/[2,3]
+     * behave accordingly...
+     */
+    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt))
+	send_badsig(prt);
+    else {
+	ErlDrvSizeT size = evp->size;
+
+	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt)	
+			   || ERTS_IS_CRASH_DUMPING);
+
+#ifdef USE_VM_PROBES
+	if (DTRACE_ENABLED(driver_outputv)) {
+	    DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
+	    DTRACE4(driver_outputv, process_str, port_str, prt->name, size);
+	}
+#endif
+
+	prt->caller = caller;
+	(*drv->outputv)((ErlDrvData) prt->drv_data, evp);
+	prt->caller = NIL;
+
+	prt->bytes_out += size;
+	erts_smp_atomic_add_nob(&erts_bytes_out, size);
+    }
+}
+
+static ERTS_INLINE void
+cleanup_scheduled_outputv(ErlIOVec *ev, ErlDrvBinary *cbinp)
+{
+    int i;
+    /* Need to free all binaries */
+    for (i = 1; i < ev->vsize; i++)
+	if (ev->binv[i])
+	    driver_free_binary(ev->binv[i]);
+    if (cbinp)
+	driver_free_binary(cbinp);
+    erts_free(ERTS_ALC_T_DRV_CMD_DATA, ev);
+}
+
+static int
+port_sig_outputv(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    Eterm reply;
+
+    switch (op) {
+    case ERTS_PROC2PORT_SIG_EXEC:
+	/* Execution of a scheduled outputv() call */
+
+	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
+
+	if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+	    reply = am_badarg;
+	else {
+	    call_driver_outputv(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
+				sigdp->caller,
+				sigdp->u.outputv.from,
+				prt,
+				prt->drv_ptr,
+				sigdp->u.outputv.evp);
+	    reply = am_true;
+	}
+	break;
+    case ERTS_PROC2PORT_SIG_ABORT_NOSUSPEND:
+	reply = am_false;
+	break;
+    default:
+	reply = am_badarg;
+	break;
+    }
+
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, reply);
+
+    cleanup_scheduled_outputv(sigdp->u.outputv.evp,
+			      sigdp->u.outputv.cbinp);
+
+    return ERTS_PORT_REDS_CMD_OUTPUTV;
+}
+
+/*
+ * Driver output() callback
+ */
+
+static ERTS_INLINE void
+call_driver_output(int bang_op,
+		   Eterm caller,
+		   Eterm from,
+		   Port *prt,
+		   erts_driver_t *drv,
+		   char *bufp,
+		   ErlDrvSizeT size)
+{
+    /*
+     * if (bang_op)
+     *   we are part of a "Prt ! {From, {command, Data}}" operation
+     * else
+     *   we are part of a call to port_command/[2,3]
+     * behave accordingly...
+     */
+    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt))
+	send_badsig(prt);
+    else {
+
+	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt)	
+			   || ERTS_IS_CRASH_DUMPING);
+
+#ifdef USE_VM_PROBES
+	if (DTRACE_ENABLED(driver_output)) {
+	    DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
+	    DTRACE4(driver_output, process_str, port_str, prt->name, size);
+	}
+#endif
+
+	prt->caller = caller;
+	(*drv->output)((ErlDrvData) prt->drv_data, bufp, size);
+	prt->caller = NIL;
+
+	prt->bytes_out += size;
+	erts_smp_atomic_add_nob(&erts_bytes_out, size);
+    }
+}
+
+static ERTS_INLINE void
+cleanup_scheduled_output(char *bufp)
+{
+    erts_free(ERTS_ALC_T_DRV_CMD_DATA, bufp);
+}
+
+static int
+port_sig_output(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    Eterm reply;
+
+    switch (op) {
+    case ERTS_PROC2PORT_SIG_EXEC:
+	/* Execution of a scheduled output() call */
+
+	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
+
+	if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+	    reply = am_badarg;
+	else {
+	    call_driver_output(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
+			       sigdp->caller,
+			       sigdp->u.output.from,
+			       prt,
+			       prt->drv_ptr,
+			       sigdp->u.output.bufp,
+			       sigdp->u.output.size);
+	    reply = am_true;
+	}
+	break;
+    case ERTS_PROC2PORT_SIG_ABORT_NOSUSPEND:
+	reply = am_false;
+	break;
+    default:
+	reply = am_badarg;
+	break;
+    }
+
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, reply);
+
+    cleanup_scheduled_output(sigdp->u.output.bufp);
+
+    return ERTS_PORT_REDS_CMD_OUTPUT;
+}
+
+ErtsPortOpResult
+erts_port_output(Process *c_p,
+		 int flags,
+		 Port *prt,
+		 Eterm from,
+		 Eterm list,
+		 Eterm *refp)
+{
+    ErtsPortOpResult res;
+    ErtsProc2PortSigData *sigdp;
+    erts_driver_t *drv = prt->drv_ptr;
+    size_t size;
+    int try_call;
+    erts_aint32_t sched_flags, busy_flgs, invalid_flags;
+    int task_flags;
+    ErtsProc2PortSigCallback port_sig_callback;
+    ErlDrvBinary *cbin = NULL;
+    ErlIOVec *evp = NULL;
+    char *buf = NULL;
+    int force_immediate_call = (flags & ERTS_PORT_SIG_FLG_FORCE_IMM_CALL);
+
+    ASSERT((flags & ~(ERTS_PORT_SIG_FLG_BANG_OP
+		      | ERTS_PORT_SIG_FLG_NOSUSPEND
+		      | ERTS_PORT_SIG_FLG_FORCE
+		      | ERTS_PORT_SIG_FLG_FORCE_IMM_CALL)) == 0);
+
+    busy_flgs = ((flags & ERTS_PORT_SIG_FLG_FORCE)
+		 ? ((erts_aint32_t) 0)
+		 : ERTS_PTS_FLGS_BUSY);
+    invalid_flags = busy_flgs;
+    if (!refp)
+	invalid_flags |= ERTS_PTS_FLG_PARALLELISM;
+
+    /*
+     * Assumes caller have checked that port is valid...
+     */
+
+    sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+    if (sched_flags & (busy_flgs|ERTS_PTS_FLG_EXIT))
+	return ((sched_flags & ERTS_PTS_FLG_EXIT)
+		? ERTS_PORT_OP_DROPPED
+		: ERTS_PORT_OP_BUSY);
+
+    try_call = (force_immediate_call /* crash dumping */
+		|| !(sched_flags & (invalid_flags
+				    | ERTS_PTS_FLGS_FORCE_SCHEDULE_OP)));
+
+#ifdef USE_VM_PROBES
+    if(DTRACE_ENABLED(port_command)) {
+	DTRACE_FORMAT_COMMON_PID_AND_PORT(c_p ? c_p->common.id : ERTS_INVALID_PID, prt);
+	DTRACE4(port_command, process_str, port_str, prt->name, "command");
+    }
+#endif
+
+    if (drv->outputv) {
+	ErlIOVec ev;
 	SysIOVec iv[SMALL_WRITE_VEC];
 	ErlDrvBinary* bv[SMALL_WRITE_VEC];
 	SysIOVec* ivp;
 	ErlDrvBinary**  bvp;
-	ErlDrvBinary* cbin;
-	ErlIOVec ev;
+	int vsize;
+	Uint csize;
+	Uint pvsize;
+	Uint pcsize;
+	Uint blimit;
+	size_t iov_offset, binv_offset, alloc_size;
 
-	if (io_list_vec_len(list, &vsize, &csize,
-			    &pvsize, &pcsize, &size)) {
+	if (io_list_vec_len(list, &vsize, &csize, &pvsize, &pcsize, &size))
 	    goto bad_value;
+
+	iov_offset = ERTS_ALC_DATA_ALIGN_SIZE(sizeof(ErlIOVec));
+	binv_offset = iov_offset;
+	binv_offset += ERTS_ALC_DATA_ALIGN_SIZE((vsize+1)*sizeof(SysIOVec));
+	alloc_size = binv_offset;
+	alloc_size += (vsize+1)*sizeof(ErlDrvBinary *);
+
+	if (try_call && vsize < SMALL_WRITE_VEC) {
+	    ivp = ev.iov = iv;
+	    bvp = ev.binv = bv;
+	    evp = &ev;
+	}
+	else {
+	    char *ptr = erts_alloc((try_call
+				    ? ERTS_ALC_T_TMP
+				    : ERTS_ALC_T_DRV_CMD_DATA), alloc_size);
+
+	    evp = (ErlIOVec *) ptr;
+	    ivp = evp->iov = (SysIOVec *) (ptr + iov_offset);
+	    bvp = evp->binv = (ErlDrvBinary **) (ptr + binv_offset);
 	}
+
 	/* To pack or not to pack (small binaries) ...? */
-	vsize++;
-	if (vsize <= SMALL_WRITE_VEC) {
+	if (vsize < SMALL_WRITE_VEC) {
 	    /* Do NOT pack */
 	    blimit = 0;
-	} else {
+	}
+	else {
 	    /* Do pack */
 	    vsize = pvsize + 1;
 	    csize = pcsize;
 	    blimit = ERL_SMALL_IO_BIN_LIMIT;
 	}
 	/* Use vsize and csize from now on */
-	if (vsize <= SMALL_WRITE_VEC) {
-	    ivp = iv;
-	    bvp = bv;
-	} else {
-	    ivp = (SysIOVec *) erts_alloc(ERTS_ALC_T_TMP,
-					  vsize * sizeof(SysIOVec));
-	    bvp = (ErlDrvBinary**) erts_alloc(ERTS_ALC_T_TMP,
-					      vsize * sizeof(ErlDrvBinary*));
-	}
+
 	cbin = driver_alloc_binary(csize);
 	if (!cbin)
 	    erts_alloc_enomem(ERTS_ALC_T_DRV_BINARY, ERTS_SIZEOF_Binary(csize));
@@ -1178,210 +1890,759 @@ int erts_write_to_port(Eterm caller_id, Port *p, Eterm list)
 	ivp[0].iov_base = NULL;
 	ivp[0].iov_len = 0;
 	bvp[0] = NULL;
-	ev.vsize = io_list_to_vec(list, ivp+1, bvp+1, cbin, blimit);
-	if (ev.vsize < 0) {
-	    if (ivp != iv) {
-		erts_free(ERTS_ALC_T_TMP, (void *) ivp);
-	    }
-	    if (bvp != bv) {
-		erts_free(ERTS_ALC_T_TMP, (void *) bvp);
-	    }
+	evp->vsize = io_list_to_vec(list, ivp+1, bvp+1, cbin, blimit);
+	if (evp->vsize < 0) {
+	    if (evp != &ev)
+		erts_free(try_call ? ERTS_ALC_T_TMP : ERTS_ALC_T_DRV_CMD_DATA,
+			  evp);
 	    driver_free_binary(cbin);
 	    goto bad_value;
 	}
-	ev.vsize++;
 #if 0
 	/* This assertion may say something useful, but it can
 	   be falsified during the emulator test suites. */
-	ASSERT(ev.vsize == vsize);
+	ASSERT(evp->vsize == vsize);
 #endif
-	ev.size = size;  /* total size */
-	ev.iov = ivp;
-	ev.binv = bvp;
-#ifdef USE_VM_PROBES
-        if (DTRACE_ENABLED(driver_outputv)) {
-            DTRACE_FORMAT_COMMON_PID_AND_PORT(caller_id, p)
-            DTRACE4(driver_outputv, process_str, port_str, p->name, size);
-        }
-#endif
-	fpe_was_unmasked = erts_block_fpe();
-	(*drv->outputv)((ErlDrvData)p->drv_data, &ev);
-	erts_unblock_fpe(fpe_was_unmasked);
-	if (ivp != iv) {
-	    erts_free(ERTS_ALC_T_TMP, (void *) ivp);
-	}
-	if (bvp != bv) {
-	    erts_free(ERTS_ALC_T_TMP, (void *) bvp);
+	evp->vsize++;
+	evp->size = size;  /* total size */
+
+	if (!try_call) {
+	    int i;
+	    /* Need to increase refc on all binaries */
+	    for (i = 1; i < evp->vsize; i++)
+		if (bvp[i])
+		    driver_binary_inc_refc(bvp[i]);
 	}
-	driver_free_binary(cbin);
-    } else {
-	int r;
-	
-	/* Try with an 8KB buffer first (will often be enough I guess). */
-	size = 8*1024;
-	/* See below why the extra byte is added. */
-	buf = erts_alloc(ERTS_ALC_T_TMP, size+1);
-	r = io_list_to_buf(list, buf, size);
+	else {
+	    int i;
+	    ErlIOVec *new_evp;
+	    ErtsTryImmDrvCallResult try_call_res;
+	    ErtsTryImmDrvCallState try_call_state
+		= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+		    c_p,
+		    prt,
+		    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+		    invalid_flags,
+		    !refp,
+		    am_command);
+
+	    try_call_state.pre_chk_sched_flags = 0; /* already checked */
+	    if (force_immediate_call)
+		try_call_res = force_imm_drv_call(&try_call_state);
+	    else
+		try_call_res = try_imm_drv_call(&try_call_state);
+	    switch (try_call_res) {
+	    case ERTS_TRY_IMM_DRV_CALL_OK:
+		call_driver_outputv(flags & ERTS_PORT_SIG_FLG_BANG_OP,
+				    c_p ? c_p->common.id : ERTS_INVALID_PID,
+				    from,
+				    prt,
+				    drv,
+				    evp);
+		if (force_immediate_call)
+		    finalize_force_imm_drv_call(&try_call_state);
+		else
+		    finalize_imm_drv_call(&try_call_state);
+		/* Fall through... */
+	    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+		driver_free_binary(cbin);
+		if (evp != &ev)
+		    erts_free(ERTS_ALC_T_TMP, evp);
+		if (try_call_res == ERTS_TRY_IMM_DRV_CALL_OK)
+		    return ERTS_PORT_OP_DONE;
+		else
+		    return ERTS_PORT_OP_DROPPED;
+	    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+		sched_flags = try_call_state.sched_flags;
+	    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+		/* Schedule outputv() call instead... */
+		break;
+	    }
 
-#ifdef USE_VM_PROBES
-	if(DTRACE_ENABLED(port_command)) {
-            DTRACE_FORMAT_COMMON_PID_AND_PORT(caller_id, p)
-	    DTRACE4(port_command, process_str, port_str, p->name, "command");
-	}
+	    /* Need to increase refc on all binaries */
+	    for (i = 1; i < evp->vsize; i++)
+		if (bvp[i])
+		    driver_binary_inc_refc(bvp[i]);
+
+	    new_evp = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, alloc_size);
+
+	    if (evp != &ev) {
+		sys_memcpy((void *) new_evp, (void *) evp, alloc_size);
+		new_evp->iov = (SysIOVec *) (((char *) new_evp)
+					     + iov_offset);
+		bvp = new_evp->binv = (ErlDrvBinary **) (((char *) new_evp)
+							 + binv_offset);
+
+#ifdef DEBUG
+		ASSERT(new_evp->vsize == evp->vsize);
+		ASSERT(new_evp->size == evp->size);
+		for (i = 0; i < evp->vsize; i++) {
+		    ASSERT(new_evp->iov[i].iov_len == evp->iov[i].iov_len);
+		    ASSERT(new_evp->iov[i].iov_base == evp->iov[i].iov_base);
+		    ASSERT(new_evp->binv[i] == evp->binv[i]);
+		}
 #endif
 
-	if (r >= 0) {
-	    size -= r;
-#ifdef USE_VM_PROBES
-            if (DTRACE_ENABLED(driver_output)) {
-                DTRACE_FORMAT_COMMON_PID_AND_PORT(caller_id, p)
-                DTRACE4(driver_output, process_str, port_str, p->name, size);
-            }
+		erts_free(ERTS_ALC_T_TMP, evp);
+	    }
+	    else { /* from stack allocated structure; offsets may differ */
+
+		sys_memcpy((void *) new_evp, (void *) evp, sizeof(ErlIOVec));
+		new_evp->iov = (SysIOVec *) (((char *) new_evp)
+					     + iov_offset);
+		sys_memcpy((void *) new_evp->iov,
+			   (void *) evp->iov,
+			   evp->vsize * sizeof(SysIOVec));
+		new_evp->binv = (ErlDrvBinary **) (((char *) new_evp)
+						   + binv_offset);
+		sys_memcpy((void *) new_evp->binv,
+			   (void *) evp->binv,
+			   evp->vsize * sizeof(ErlDrvBinary *));
+
+#ifdef DEBUG
+		ASSERT(new_evp->vsize == evp->vsize);
+		ASSERT(new_evp->size == evp->size);
+		for (i = 0; i < evp->vsize; i++) {
+		    ASSERT(new_evp->iov[i].iov_len == evp->iov[i].iov_len);
+		    ASSERT(new_evp->iov[i].iov_base == evp->iov[i].iov_base);
+		    ASSERT(new_evp->binv[i] == evp->binv[i]);
+		}
 #endif
-	    fpe_was_unmasked = erts_block_fpe();
-	    (*drv->output)((ErlDrvData)p->drv_data, buf, size);
-	    erts_unblock_fpe(fpe_was_unmasked);
-	    erts_free(ERTS_ALC_T_TMP, buf);
+
+	    }
+
+	    evp = new_evp;
 	}
-	else if (r == -2) {
-	    erts_free(ERTS_ALC_T_TMP, buf);
-	    goto bad_value;
+
+	sigdp = erts_port_task_alloc_p2p_sig_data();
+	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUTV;
+	sigdp->u.outputv.from = from;
+	sigdp->u.outputv.evp = evp;
+	sigdp->u.outputv.cbinp = cbin;
+	port_sig_callback = port_sig_outputv;
+    }
+    else {
+	ErlDrvSizeT r;
+
+	/*
+	 * Apperently there exist code that write 1 byte to
+	 * much in buffer. Where it resides I don't know, but
+	 * we can live with one byte extra allocated...
+	 */
+
+	if (!try_call) {
+	    if (erts_iolist_size(list, &size))
+		goto bad_value;
+
+	    buf = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, size + 1);
+
+	    r = erts_iolist_to_buf(list, buf, size);
+	    ASSERT(ERTS_IOLIST_TO_BUF_SUCCEEDED(r));
 	}
 	else {
-	    ASSERT(r == -1); /* Overflow */
-	    erts_free(ERTS_ALC_T_TMP, buf);
-	    if (erts_iolist_size(list, &size)) {
-		goto bad_value;
+	    char *new_buf;
+	    ErtsTryImmDrvCallResult try_call_res;
+	    ErtsTryImmDrvCallState try_call_state
+		= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+		    c_p,
+		    prt,
+		    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+		    invalid_flags,
+		    !refp,
+		    am_command);
+
+	    /* Try with an 8KB buffer first (will often be enough I guess). */
+	    size = 8*1024;
+
+	    buf = erts_alloc(ERTS_ALC_T_TMP, size + 1);
+	    r = erts_iolist_to_buf(list, buf, size);
+
+	    if (ERTS_IOLIST_TO_BUF_SUCCEEDED(r)) {
+		ASSERT(r <= size);
+		size -= r;
+	    }
+	    else {
+		erts_free(ERTS_ALC_T_TMP, buf);
+		if (r == ERTS_IOLIST_TO_BUF_TYPE_ERROR)
+		    goto bad_value;
+		ASSERT(r == ERTS_IOLIST_TO_BUF_OVERFLOW);
+		if (erts_iolist_size(list, &size))
+		    goto bad_value;
+		buf = erts_alloc(ERTS_ALC_T_TMP, size + 1); 
+		r = erts_iolist_to_buf(list, buf, size);
+		ASSERT(ERTS_IOLIST_TO_BUF_SUCCEEDED(r));
 	    }
 
-	    /*
-	     * I know drivers that pad space with '\0' this is clearly
-	     * incorrect but I don't feel like fixing them now, insted
-	     * add ONE extra byte.
-	     */
-	    buf = erts_alloc(ERTS_ALC_T_TMP, size+1); 
-	    r = io_list_to_buf(list, buf, size);
-#ifdef USE_VM_PROBES
-            if (DTRACE_ENABLED(driver_output)) {
-                DTRACE_FORMAT_COMMON_PID_AND_PORT(caller_id, p)
-                DTRACE4(driver_output, process_str, port_str, p->name, size);
-            }
-#endif
-	    fpe_was_unmasked = erts_block_fpe();
-	    (*drv->output)((ErlDrvData)p->drv_data, buf, size);
-	    erts_unblock_fpe(fpe_was_unmasked);
+	    try_call_state.pre_chk_sched_flags = 0; /* already checked */
+	    if (force_immediate_call)
+		try_call_res = force_imm_drv_call(&try_call_state);
+	    else
+		try_call_res = try_imm_drv_call(&try_call_state);
+	    switch (try_call_res) {
+	    case ERTS_TRY_IMM_DRV_CALL_OK:
+		call_driver_output(flags & ERTS_PORT_SIG_FLG_BANG_OP,
+				   c_p ? c_p->common.id : ERTS_INVALID_PID,
+				   from,
+				   prt,
+				   drv,
+				   buf,
+				   size);
+		if (force_immediate_call)
+		    finalize_force_imm_drv_call(&try_call_state);
+		else
+		    finalize_imm_drv_call(&try_call_state);
+		/* Fall through... */
+	    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+		erts_free(ERTS_ALC_T_TMP, buf);
+		if (try_call_res == ERTS_TRY_IMM_DRV_CALL_OK)
+		    return ERTS_PORT_OP_DONE;
+		else
+		    return ERTS_PORT_OP_DROPPED;
+	    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+		sched_flags = try_call_state.sched_flags;
+	    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+		/* Schedule outputv() call instead... */
+		break;
+	    }
+
+	    new_buf = erts_alloc(ERTS_ALC_T_DRV_CMD_DATA, size + 1);
+	    sys_memcpy(new_buf, buf, size);
 	    erts_free(ERTS_ALC_T_TMP, buf);
+	    buf = new_buf;
 	}
+
+	sigdp = erts_port_task_alloc_p2p_sig_data();
+	sigdp->flags = ERTS_P2P_SIG_TYPE_OUTPUT;
+	sigdp->u.output.from = from;
+	sigdp->u.output.bufp = buf;
+	sigdp->u.output.size = size;
+	port_sig_callback = port_sig_output;
+    }
+
+    task_flags = ERTS_PT_FLG_WAIT_BUSY;
+    sigdp->flags |= flags;
+    if (flags & (ERTS_P2P_SIG_DATA_FLG_FORCE|ERTS_P2P_SIG_DATA_FLG_NOSUSPEND)) {
+	task_flags = 0;
+	if (flags & ERTS_P2P_SIG_DATA_FLG_FORCE)
+	    sigdp->flags &= ~ERTS_P2P_SIG_DATA_FLG_NOSUSPEND;
+	else if (flags & ERTS_P2P_SIG_DATA_FLG_NOSUSPEND)
+	    task_flags = ERTS_PT_FLG_NOSUSPEND;
+    }
+
+    res = erts_schedule_proc2port_signal(c_p,
+					 prt,
+					 c_p ? c_p->common.id : ERTS_INVALID_PID,
+					 refp,
+					 sigdp,
+					 task_flags,
+					 port_sig_callback);
+
+    if (res != ERTS_PORT_OP_SCHEDULED) {
+	if (drv->outputv)
+	    cleanup_scheduled_outputv(evp, cbin);
+	else
+	    cleanup_scheduled_output(buf);
+	return res;
     }
-    p->bytes_out += size;
-    erts_smp_atomic_add_nob(&erts_bytes_out, size);
 
-#ifdef ERTS_SMP
-    if (p->xports)
-	erts_smp_xports_unlock(p);
-    ASSERT(!p->xports);
+    if (!(sched_flags & ERTS_PTS_FLG_EXIT) && (sched_flags & busy_flgs))
+	return ERTS_PORT_OP_BUSY_SCHEDULED;
+
+    return res;
+
+bad_value:
+
+    flags |= ERTS_PORT_SIG_FLG_BAD_OUTPUT;
+    return bad_port_signal(c_p, flags, prt, from, refp, am_command);
+}
+
+static ERTS_INLINE ErtsPortOpResult
+call_deliver_port_exit(int bang_op,
+		       Eterm from,
+		       Port *prt,
+		       erts_aint32_t state,
+		       Eterm reason,
+		       int broken_link)
+{
+    /*
+     * if (bang_op)
+     *   we are part of a "Prt ! {From, close}" operation
+     * else
+     *   we are part of a call to port_close(Port)
+     * behave accordingly...
+     */
+
+    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+	return ERTS_PORT_OP_DROPPED;
+
+    if (bang_op && from != ERTS_PORT_GET_CONNECTED(prt)) {
+	send_badsig(prt);
+	return ERTS_PORT_OP_DROPPED;
+    }
+
+    if (broken_link) {
+	ErtsLink *lnk = erts_remove_link(&ERTS_P_LINKS(prt), from);
+	if (lnk)
+	    erts_destroy_link(lnk);
+	else
+	    return ERTS_PORT_OP_DROPPED;
+    }
+
+    if (!erts_deliver_port_exit(prt, from, reason, bang_op))
+	return ERTS_PORT_OP_DROPPED;
+
+#ifdef USE_VM_PROBES
+    if(DTRACE_ENABLED(port_command) && bang_op) {
+	DTRACE_FORMAT_COMMON_PID_AND_PORT(from, prt);
+	DTRACE4(port_command, process_str, port_str, prt->name, "close");
+    }
 #endif
-    p->caller = NIL;
-    return 0;
 
- bad_value: 
-    p->caller = NIL;
-    {
-	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-	erts_dsprintf(dsbufp, "Bad value on output port '%s'\n", p->name);
-	erts_send_error_to_logger_nogl(dsbufp);
-	return 1;
+    return ERTS_PORT_OP_DONE;
+}
+
+static int
+port_sig_exit(Port *prt,
+	      erts_aint32_t state,
+	      int op,
+	      ErtsProc2PortSigData *sigdp)
+{
+    Eterm msg = am_badarg;
+    if (op == ERTS_PROC2PORT_SIG_EXEC) {
+	ErtsPortOpResult res;
+	int bang_op = sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP;
+	int broken_link = sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BROKEN_LINK;
+	res = call_deliver_port_exit(bang_op,
+				     sigdp->u.exit.from,
+				     prt,
+				     state,
+				     sigdp->u.exit.reason,
+				     broken_link);
+
+	if (res == ERTS_PORT_OP_DONE)
+	    msg = am_true;
+    }
+    if (sigdp->u.exit.bp)
+	free_message_buffer(sigdp->u.exit.bp);
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, msg);
+
+    return ERTS_PORT_REDS_EXIT;
+}
+
+ErtsPortOpResult
+erts_port_exit(Process *c_p,
+	       int flags,
+	       Port *prt,
+	       Eterm from,
+	       Eterm reason,
+	       Eterm *refp)
+{
+    ErtsPortOpResult res;
+    ErtsProc2PortSigData *sigdp;
+    ErlHeapFragment *bp = NULL;
+
+    ASSERT((flags & ~(ERTS_PORT_SIG_FLG_BANG_OP
+		      | ERTS_PORT_SIG_FLG_BROKEN_LINK
+		      | ERTS_PORT_SIG_FLG_FORCE_SCHED)) == 0);
+
+    if (!(flags & ERTS_PORT_SIG_FLG_FORCE_SCHED)) {
+	ErtsTryImmDrvCallState try_call_state
+	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
+					       prt,
+					       ERTS_PORT_SFLGS_INVALID_LOOKUP,
+					       0,
+					       !refp,
+					       am_exit);
+
+
+	switch (try_imm_drv_call(&try_call_state)) {
+	case ERTS_TRY_IMM_DRV_CALL_OK: {
+	    res = call_deliver_port_exit(flags & ERTS_PORT_SIG_FLG_BANG_OP,
+					 from,
+					 prt,
+					 try_call_state.state,
+					 reason,
+					 flags & ERTS_PORT_SIG_FLG_BROKEN_LINK);
+	    finalize_imm_drv_call(&try_call_state);
+	    return res;
+	}
+	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	    return ERTS_PORT_OP_DROPPED;
+	default:
+	    /* Schedule call instead... */
+	    break;
+	}
     }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_EXIT | flags;
+    sigdp->u.exit.from = from;
+
+    if (is_immed(reason)) {
+	sigdp->u.exit.reason = reason;
+	sigdp->u.exit.bp = NULL;
+    }
+    else {
+	Eterm *hp;
+	Uint hsz = size_object(reason);
+	bp = new_message_buffer(hsz);
+	sigdp->u.exit.bp = bp;
+	hp = bp->mem;
+	sigdp->u.exit.reason = copy_struct(reason,
+					   hsz,
+					   &hp,
+					   &bp->off_heap);
+    }
+
+    res = erts_schedule_proc2port_signal(c_p,
+					 prt,
+					 c_p ? c_p->common.id : from,
+					 refp,
+					 sigdp,
+					 0,
+					 port_sig_exit);
+
+    if (res == ERTS_PORT_OP_DROPPED) {
+	if (bp)
+	    free_message_buffer(bp);
+    }
+
+    return res;
 }
 
-/* initialize the port array */
-void init_io(void)
+static ErtsPortOpResult
+set_port_connected(int bang_op,
+		   Eterm from,
+		   Port *prt,
+		   erts_aint32_t state,
+		   Eterm connect)
 {
-    int i;
-    ErlDrvEntry** dp;
-    char maxports[21]; /* enough for any 64-bit integer */
-    size_t maxportssize = sizeof(maxports);
-    Uint ports_bits = ERTS_PORTS_BITS;
-    Sint port_extra_shift;
+    /*
+     * if (bang_op)
+     *   we are part of a "Prt ! {From, {connect, Connect}}" operation
+     * else
+     *   we are part of a call to port_connect(Port, Connect)
+     * behave accordingly...
+     */
 
-#ifdef ERTS_SMP
-    init_xports_list_alloc();
+    if (state & ERTS_PORT_SFLGS_INVALID_LOOKUP)
+	return ERTS_PORT_OP_DROPPED;
+
+    if (bang_op) { /* Bang operation */
+	if (is_not_internal_pid(connect) || ERTS_PORT_GET_CONNECTED(prt) != from) {
+	    send_badsig(prt);
+	    return ERTS_PORT_OP_DROPPED;
+	}
+
+	ERTS_PORT_SET_CONNECTED(prt, connect);
+	deliver_result(prt->common.id, from, am_connected);
+
+#ifdef USE_VM_PROBES
+	if(DTRACE_ENABLED(port_command)) {
+	    DTRACE_FORMAT_COMMON_PID_AND_PORT(from, prt);
+	    DTRACE4(port_command, process_str, port_str, prt->name, "connect");
+	}
 #endif
+    }
+    else { /* Port BIF operation */
+	Process *rp = erts_proc_lookup_raw(connect);
+	if (!rp)
+	    return ERTS_PORT_OP_DROPPED;
+	erts_smp_proc_lock(rp, ERTS_PROC_LOCK_LINK);
+	if (ERTS_PROC_IS_EXITING(rp)) {
+	    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+	    return ERTS_PORT_OP_DROPPED;
+	}
 
-    pdl_init();
+	erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, prt->common.id);
+	erts_add_link(&ERTS_P_LINKS(prt), LINK_PID, connect);
+
+	ERTS_PORT_SET_CONNECTED(prt, connect);
+
+	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
+
+#ifdef USE_VM_PROBES
+	if (DTRACE_ENABLED(port_connect)) {
+	    DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);
+	    DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);
+	    DTRACE_CHARBUF(newprocess_str, DTRACE_TERM_BUF_SIZE);
+
+	    dtrace_pid_str(connect, process_str);
+	    erts_snprintf(port_str, sizeof(port_str), "%T", prt->common.id);
+	    dtrace_proc_str(rp, newprocess_str);
+	    DTRACE4(port_connect, process_str, port_str, prt->name, newprocess_str);
+	}
+#endif
+    }
+
+    return ERTS_PORT_OP_DONE;
+}
 
-    if (erts_sys_getenv_raw("ERL_MAX_PORTS", maxports, &maxportssize) == 0) 
-	erts_max_ports = atoi(maxports);
+static int
+port_sig_connect(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    Eterm msg = am_badarg;
+    if (op == ERTS_PROC2PORT_SIG_EXEC) {
+	ErtsPortOpResult res;
+	res = set_port_connected(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_BANG_OP,
+				 sigdp->u.connect.from,
+				 prt,
+				 state,
+				 sigdp->u.connect.connected);
+	if (res == ERTS_PORT_OP_DONE)
+	    msg = am_true;
+    }
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, msg);
+    return ERTS_PORT_REDS_CONNECT;
+}
+
+ErtsPortOpResult
+erts_port_connect(Process *c_p,
+		  int flags,
+		  Port *prt,
+		  Eterm from,
+		  Eterm connect,
+		  Eterm *refp)
+{
+    ErtsProc2PortSigData *sigdp;
+    Eterm connect_id;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
+					   prt,
+					   ERTS_PORT_SFLGS_INVALID_LOOKUP,
+					   0,
+					   !refp,
+					   am_connect);
+
+    ASSERT((flags & ~ERTS_PORT_SIG_FLG_BANG_OP) == 0);
+
+    if (is_not_internal_pid(connect))
+	connect_id = NIL; /* Fail in op (for signal order) */
     else
-	erts_max_ports = sys_max_files();
+	connect_id = connect;
+
+    switch (try_imm_drv_call(&try_call_state)) {
+    case ERTS_TRY_IMM_DRV_CALL_OK: {
+	ErtsPortOpResult res;
+	res = set_port_connected(flags & ERTS_PORT_SIG_FLG_BANG_OP,
+				 from,
+				 prt,
+				 try_call_state.state,
+				 connect_id);
+	finalize_imm_drv_call(&try_call_state);
+	return res;
+    }
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    default:
+	/* Schedule call instead... */
+	break;
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_CONNECT | flags;
+
+    sigdp->u.connect.from = from;
+    sigdp->u.connect.connected = connect_id;
+    
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p->common.id,
+					  refp,
+					  sigdp,
+					  0,
+					  port_sig_connect);
+}
 
-    if (erts_max_ports > ERTS_MAX_PORTS)
-	erts_max_ports = ERTS_MAX_PORTS;
-    if (erts_max_ports < 1024)
-	erts_max_ports = 1024;
+static void
+port_unlink(Port *prt, Eterm from)
+{
+    ErtsLink *lnk = erts_remove_link(&ERTS_P_LINKS(prt), from);
+    if (lnk)
+	erts_destroy_link(lnk);
+}
 
-    if (erts_use_r9_pids_ports) {
-	ports_bits = ERTS_R9_PORTS_BITS;
-	if (erts_max_ports > ERTS_MAX_R9_PORTS)
-	    erts_max_ports = ERTS_MAX_R9_PORTS;
+static int
+port_sig_unlink(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    if (op == ERTS_PROC2PORT_SIG_EXEC)
+	port_unlink(prt, sigdp->u.unlink.from);
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_true);
+    return ERTS_PORT_REDS_UNLINK;
+}
+
+ErtsPortOpResult
+erts_port_unlink(Process *c_p, Port *prt, Eterm from, Eterm *refp)
+{
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
+					   prt,
+					   ERTS_PORT_SFLGS_DEAD,
+					   0,
+					   !refp,
+					   am_unlink);
+
+    switch (try_imm_drv_call(&try_call_state)) {
+    case ERTS_TRY_IMM_DRV_CALL_OK:
+	port_unlink(prt, from);
+	finalize_imm_drv_call(&try_call_state);
+	return ERTS_PORT_OP_DONE;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    default:
+	/* Schedule call instead... */
+	break;
     }
 
-    port_extra_shift = erts_fit_in_bits_int32(erts_max_ports - 1);
-    port_num_mask = (1 << ports_bits) - 1;
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_UNLINK;
+    sigdp->u.unlink.from = from;
+    
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p ? c_p->common.id : from,
+					  refp,
+					  sigdp,
+					  0,
+					  port_sig_unlink);
+}
 
-    erts_port_tab_index_mask = ~(~((Uint) 0) << port_extra_shift);
-    erts_max_ports = 1 << port_extra_shift;
+static void
+port_link_failure(Eterm port_id, Eterm linker)
+{
+    Process *rp;
+    ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
+    ASSERT(is_internal_pid(linker));
+    rp = erts_pid2proc(NULL, 0, linker, rp_locks);
+    if (rp) {
+	ErtsLink *rlnk = erts_remove_link(&ERTS_P_LINKS(rp), port_id);
+	if (rlnk) {
+	    int xres = erts_send_exit_signal(NULL,
+					     port_id,
+					     rp,
+					     &rp_locks, 
+					     am_noproc,
+					     NIL,
+					     NULL,
+					     0);
+	    if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
+		/* We didn't exit the process and it is traced */
+		if (IS_TRACED_FL(rp, F_TRACE_PROCS))
+		    trace_proc(NULL, rp, am_getting_unlinked, port_id);
+	    }
+	}
+    }
+}
 
-    erts_smp_mtx_init(&erts_driver_list_lock,"driver_list");
-    driver_list = NULL;
-    erts_smp_tsd_key_create(&driver_list_lock_status_key);
-    erts_smp_tsd_key_create(&driver_list_last_error_key);
+static void
+port_link(Port *prt, erts_aint32_t state, Eterm to)
+{
+    if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP))
+	erts_add_link(&ERTS_P_LINKS(prt), LINK_PID, to);
+    else
+	port_link_failure(prt->common.id, to);
+}
 
-    if (erts_max_ports * sizeof(Port) <= erts_max_ports) {
-	/* More memory needed than the whole address space. */
-	erts_alloc_enomem(ERTS_ALC_T_PORT_TABLE, ~((Uint) 0));
+static int
+port_sig_link(Port *prt, erts_aint32_t state, int op, ErtsProc2PortSigData *sigdp)
+{
+    if (op == ERTS_PROC2PORT_SIG_EXEC)
+	port_link(prt, state, sigdp->u.link.to);
+    else
+	port_link_failure(sigdp->u.link.port, sigdp->u.link.to);
+    if (sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_true);
+    return ERTS_PORT_REDS_LINK;
+}
+
+ErtsPortOpResult
+erts_port_link(Process *c_p, Port *prt, Eterm to, Eterm *refp)
+{
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(c_p,
+					   prt,
+					   ERTS_PORT_SFLGS_INVALID_LOOKUP,
+					   0,
+					   !refp,
+					   am_link);
+
+    switch (try_imm_drv_call(&try_call_state)) {
+    case ERTS_TRY_IMM_DRV_CALL_OK:
+	port_link(prt, try_call_state.state, to);
+	finalize_imm_drv_call(&try_call_state);
+	return ERTS_PORT_OP_DONE;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_BADARG;
+    default:
+	/* Schedule call instead... */
+	break;
     }
 
-    erts_port = (Port *) erts_alloc(ERTS_ALC_T_PORT_TABLE,
-				    erts_max_ports * sizeof(Port));
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_LINK;
+    sigdp->u.link.port = prt->common.id;
+    sigdp->u.link.to = to;
+    
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p ? c_p->common.id : to,
+					  refp,
+					  sigdp,
+					  0,
+					  port_sig_link);
+}
 
-    erts_smp_atomic_init_nob(&erts_bytes_out, 0);
-    erts_smp_atomic_init_nob(&erts_bytes_in, 0);
+void erts_init_io(int port_tab_size,
+		  int port_tab_size_ignore_files)
+{
+    ErlDrvEntry** dp;
+    erts_smp_rwmtx_opt_t drv_list_rwmtx_opts = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
+    drv_list_rwmtx_opts.type = ERTS_SMP_RWMTX_TYPE_EXTREMELY_FREQUENT_READ;
+    drv_list_rwmtx_opts.lived = ERTS_SMP_RWMTX_LONG_LIVED;
 
-    for (i = 0; i < erts_max_ports; i++) {
-	erts_port_task_init_sched(&erts_port[i].sched);
-	erts_smp_atomic_init_nob(&erts_port[i].refc, 0);
 #ifdef ERTS_SMP
-	erts_port[i].lock = NULL;
-	erts_port[i].xports = NULL;
-	erts_smp_spinlock_init_x(&erts_port[i].state_lck,
-#ifdef ERTS_ENABLE_LOCK_COUNT
-				 (erts_lcnt_rt_options & ERTS_LCNT_OPT_PORTLOCK) ? "port_state" : NULL,
-#else
-				 "port_state",
-#endif
-				 make_small(0));
+    init_xports_list_alloc();
 #endif
-	erts_port[i].tracer_proc = NIL;
-	erts_port[i].trace_flags = 0;
 
-	erts_port[i].drv_ptr = NULL;
-	erts_port[i].status = ERTS_PORT_SFLG_FREE;
-	erts_port[i].name = NULL;
-	erts_port[i].nlinks = NULL;
-	erts_port[i].monitors = NULL;
-	erts_port[i].linebuf = NULL;
-	erts_port[i].port_data_lock = NULL;
+    pdl_init();
+
+    if (!port_tab_size_ignore_files) {
+	int max_files = sys_max_files();
+	if (port_tab_size < max_files)
+	    port_tab_size = max_files;
     }
 
-    erts_smp_atomic32_init_nob(&erts_ports_snapshot, (erts_aint32_t) 0);
-    last_port_num = 0;
-    erts_smp_spinlock_init(&get_free_port_lck, "get_free_port");
+    if (port_tab_size > ERTS_MAX_PORTS)
+	port_tab_size = ERTS_MAX_PORTS;
+    else if (port_tab_size < ERTS_MIN_PORTS)
+	port_tab_size = ERTS_MIN_PORTS;
+
+    erts_smp_rwmtx_init_opt(&erts_driver_list_lock,
+			    &drv_list_rwmtx_opts,
+			    "driver_list");
+    driver_list = NULL;
+    erts_smp_tsd_key_create(&driver_list_lock_status_key);
+    erts_smp_tsd_key_create(&driver_list_last_error_key);
+
+    erts_ptab_init_table(&erts_port,
+			 ERTS_ALC_T_PORT_TABLE,
+			 NULL,
+			 (ErtsPTabElementCommon *) &erts_invalid_port.common,
+			 port_tab_size,
+			 "port_table");
+
+    erts_smp_atomic_init_nob(&erts_bytes_out, 0);
+    erts_smp_atomic_init_nob(&erts_bytes_in, 0);
 
     sys_init_io();
 
     erts_smp_tsd_set(driver_list_lock_status_key, (void *) 1);
-    erts_smp_mtx_lock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rwlock(&erts_driver_list_lock);
 
     init_driver(&fd_driver, &fd_driver_entry, NULL);
     init_driver(&vanilla_driver, &vanilla_driver_entry, NULL);
@@ -1390,27 +2651,63 @@ void init_io(void)
 	erts_add_driver_entry(*dp, NULL, 1);
 
     erts_smp_tsd_set(driver_list_lock_status_key, NULL);
-    erts_smp_mtx_unlock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
 }
 
 #if defined(ERTS_ENABLE_LOCK_COUNT) && defined(ERTS_SMP)
-void erts_lcnt_enable_io_lock_count(int enable) {
-    int i;
 
-    for (i = 0; i < erts_max_ports; i++) {
-	Port* p = &erts_port[i];
-	if (enable) {
-	    erts_lcnt_init_lock_x(&p->state_lck.lcnt, "port_state", ERTS_LCNT_LT_SPINLOCK, make_small(i));
-	    if (p->lock) {
-		erts_lcnt_init_lock_x(&p->lock->lcnt, "port_lock", ERTS_LCNT_LT_MUTEX, make_small(i));
-	    }
-	} else {
-	    erts_lcnt_destroy_lock(&p->state_lck.lcnt);
-	    if (p->lock) {
-		erts_lcnt_destroy_lock(&p->lock->lcnt);
-	    }
-	}
+static ERTS_INLINE void lcnt_enable_drv_lock_count(erts_driver_t *dp, int enable)
+{
+    if (dp->lock) {
+	if (enable)
+	    erts_lcnt_init_lock_x(&dp->lock->lcnt,
+				  "driver_lock",
+				  ERTS_LCNT_LT_MUTEX,
+				  am_atom_put(dp->name,
+					      sys_strlen(dp->name)));
+	else
+	    erts_lcnt_destroy_lock(&dp->lock->lcnt);
+
+    }
+}
+
+static ERTS_INLINE void lcnt_enable_port_lock_count(Port *prt, int enable)
+{
+    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);
+    if (!enable) {
+	erts_lcnt_destroy_lock(&prt->sched.mtx.lcnt);
+	if (state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK)
+	    erts_lcnt_destroy_lock(&prt->lock->lcnt);
     }
+    else {
+	erts_lcnt_init_lock_x(&prt->sched.mtx.lcnt,
+			      "port_sched_lock",
+			      ERTS_LCNT_LT_MUTEX,
+			      prt->common.id);
+	if (state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK)
+	    erts_lcnt_init_lock_x(&prt->lock->lcnt,
+				  "port_lock",
+				  ERTS_LCNT_LT_MUTEX,
+				  prt->common.id);
+    }
+}
+
+void erts_lcnt_enable_io_lock_count(int enable)
+{
+    erts_driver_t *dp;
+    int i, max = erts_ptab_max(&erts_port);
+
+    for (i = 0; i < max; i++) {
+	Port *prt = erts_pix2port(i);
+	if (prt)
+	    lcnt_enable_port_lock_count(prt, enable);
+    }
+
+    lcnt_enable_drv_lock_count(&vanilla_driver, enable);
+    lcnt_enable_drv_lock_count(&spawn_driver, enable);
+    lcnt_enable_drv_lock_count(&fd_driver, enable);
+    for (dp = driver_list; dp; dp = dp->next)
+	lcnt_enable_drv_lock_count(dp, enable);
 }
 #endif
 
@@ -1594,9 +2891,7 @@ deliver_result(Eterm sender, Eterm pid, Eterm res)
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    ASSERT(is_internal_port(sender)
-	   && is_internal_pid(pid)
-	   && internal_pid_index(pid) < erts_max_processes);
+    ASSERT(is_internal_port(sender) && is_internal_pid(pid));
 
     rp = (scheduler
 	  ? erts_proc_lookup(pid)
@@ -1608,16 +2903,19 @@ deliver_result(Eterm sender, Eterm pid, Eterm res)
 	ErlOffHeap *ohp;
 	Eterm* hp;
 	Uint sz_res;
-	    sz_res = size_object(res);
-	    hp = erts_alloc_message_heap(sz_res + 3, &bp, &ohp, rp, &rp_locks);
-	    res = copy_struct(res, sz_res, &hp, ohp);
-	    tuple = TUPLE2(hp, sender, res);
+
+	sz_res = size_object(res);
+	hp = erts_alloc_message_heap(sz_res + 3, &bp, &ohp, rp, &rp_locks);
+	res = copy_struct(res, sz_res, &hp, ohp);
+	tuple = TUPLE2(hp, sender, res);
 	erts_queue_message(rp, &rp_locks, bp, tuple, NIL
 #ifdef USE_VM_PROBES
 			   , NIL
 #endif
 			   );
-	erts_smp_proc_unlock(rp, rp_locks);
+
+	if (rp_locks)
+	    erts_smp_proc_unlock(rp, rp_locks);
 	if (!scheduler)
 	    erts_smp_proc_dec_refc(rp);
 
@@ -1633,7 +2931,7 @@ deliver_result(Eterm sender, Eterm pid, Eterm res)
  * len  -- length of data
  */
 
-static void deliver_read_message(Port* prt, Eterm to,
+static void deliver_read_message(Port* prt, erts_aint32_t state, Eterm to,
 				 char *hbuf, ErlDrvSizeT hlen,
 				 char *buf, ErlDrvSizeT len, int eol)
 {
@@ -1651,10 +2949,11 @@ static void deliver_read_message(Port* prt, Eterm to,
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
     need = 3 + 3 + 2*hlen;
-    if (prt->status & ERTS_PORT_SFLG_LINEBUF_IO) {
+
+    if (state & ERTS_PORT_SFLG_LINEBUF_IO) {
 	need += 3;
     }
-    if (prt->status & ERTS_PORT_SFLG_BINARY_IO && buf != NULL) {
+    if ((state & ERTS_PORT_SFLG_BINARY_IO) && buf != NULL) {
 	need += PROC_BIN_SIZE;
     } else {
 	need += 2*len;
@@ -1670,7 +2969,7 @@ static void deliver_read_message(Port* prt, Eterm to,
     hp = erts_alloc_message_heap(need, &bp, &ohp, rp, &rp_locks);
 
     listp = NIL;
-    if ((prt->status & ERTS_PORT_SFLG_BINARY_IO) == 0) {
+    if ((state & ERTS_PORT_SFLG_BINARY_IO) == 0) {
 	listp = buf_to_intlist(&hp, buf, len, listp);
     } else if (buf != NULL) {
 	ProcBin* pb;
@@ -1701,14 +3000,14 @@ static void deliver_read_message(Port* prt, Eterm to,
 	listp = buf_to_intlist(&hp, hbuf, hlen, listp);
     }
 
-    if (prt->status & ERTS_PORT_SFLG_LINEBUF_IO){
+    if (state & ERTS_PORT_SFLG_LINEBUF_IO){
 	listp = TUPLE2(hp, (eol) ? am_eol : am_noeol, listp); 
 	hp += 3;
     }
     tuple = TUPLE2(hp, am_data, listp);
     hp += 3;
 
-    tuple = TUPLE2(hp, prt->id, tuple);
+    tuple = TUPLE2(hp, prt->common.id, tuple);
     hp += 3;
 
     erts_queue_message(rp, &rp_locks, bp, tuple, am_undefined
@@ -1726,7 +3025,8 @@ static void deliver_read_message(Port* prt, Eterm to,
  * Deliver all lines in a line buffer, repeats calls to
  * deliver_read_message, and takes the same parameters.
  */
-static void deliver_linebuf_message(Port* prt, Eterm to, 
+static void deliver_linebuf_message(Port* prt, erts_aint_t state,
+				    Eterm to, 
 				    char* hbuf, ErlDrvSizeT hlen,
 				    char *buf, ErlDrvSizeT len)
 {
@@ -1735,7 +3035,7 @@ static void deliver_linebuf_message(Port* prt, Eterm to,
     if(init_linebuf_context(&lc,&(prt->linebuf), buf, len) < 0)
 	return;
     while((ret = read_linebuf(&lc)) > LINEBUF_EMPTY)
-	deliver_read_message(prt, to, hbuf, hlen, LINEBUF_DATA(lc), 
+	deliver_read_message(prt, state, to, hbuf, hlen, LINEBUF_DATA(lc), 
 			     LINEBUF_DATALEN(lc), (ret == LINEBUF_EOL));
 }
 
@@ -1746,20 +3046,25 @@ static void deliver_linebuf_message(Port* prt, Eterm to,
  * Parameters:
  * prt -  Pointer to a Port structure for this port.
  */
-static void flush_linebuf_messages(Port *prt)
+static void flush_linebuf_messages(Port *prt, erts_aint32_t state)
 {
     LineBufContext lc;
     int ret;
 
     ERTS_SMP_LC_ASSERT(!prt || erts_lc_is_port_locked(prt));
-    if(prt == NULL || !(prt->status & ERTS_PORT_SFLG_LINEBUF_IO))
+
+    if (!prt)
+	return;
+
+    if (!(state & ERTS_PORT_SFLG_LINEBUF_IO))
 	return;
 
     if(init_linebuf_context(&lc,&(prt->linebuf), NULL, 0) < 0)
 	return;
     while((ret = flush_linebuf(&lc)) > LINEBUF_EMPTY)
 	deliver_read_message(prt,
-			     prt->connected,
+			     state,
+			     ERTS_PORT_GET_CONNECTED(prt),
 			     NULL,
 			     0,
 			     LINEBUF_DATA(lc), 
@@ -1787,6 +3092,7 @@ deliver_vec_message(Port* prt,			/* Port */
     ErlOffHeap *ohp;
     ErtsProcLocks rp_locks = 0;
     int scheduler = erts_get_scheduler_id() != 0;
+    erts_aint32_t state;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
     ERTS_SMP_CHK_NO_PROC_LOCKS;
@@ -1802,12 +3108,13 @@ deliver_vec_message(Port* prt,			/* Port */
     if (!rp)
 	return;
 
+    state = erts_atomic32_read_nob(&prt->state);
     /*
      * Calculate the exact number of heap words needed.
      */
 
     need = 3 + 3;		/* Heap space for two tuples */
-    if (prt->status & ERTS_PORT_SFLG_BINARY_IO) {
+    if (state & ERTS_PORT_SFLG_BINARY_IO) {
 	need += (2+PROC_BIN_SIZE)*vsize - 2 + hlen*2;
     } else {
 	need += (hlen+csize)*2;
@@ -1818,7 +3125,7 @@ deliver_vec_message(Port* prt,			/* Port */
     listp = NIL;
     iov += vsize;
 
-    if ((prt->status & ERTS_PORT_SFLG_BINARY_IO) == 0) {
+    if ((state & ERTS_PORT_SFLG_BINARY_IO) == 0) {
 	Eterm* thp = hp;
 	while (vsize--) {
 	    iov--;
@@ -1871,7 +3178,7 @@ deliver_vec_message(Port* prt,			/* Port */
 
     tuple = TUPLE2(hp, am_data, listp);
     hp += 3;
-    tuple = TUPLE2(hp, prt->id, tuple);
+    tuple = TUPLE2(hp, prt->common.id, tuple);
     hp += 3;
 
     erts_queue_message(rp, &rp_locks, bp, tuple, am_undefined
@@ -1904,7 +3211,7 @@ static void deliver_bin_message(Port*  prt,         /* port */
 /* 
  * Note. 
  *
- * The test for (p->status & ERTS_PORT_SFLGS_DEAD) == 0 is important since the
+ * The test for ERTS_PORT_SFLGS_DEAD is important since the
  * driver's  flush function might call driver_async, which when using no
  * threads and being short circuited will notice that the io queue is empty
  * (after calling the driver's async_ready) and recursively call 
@@ -1920,7 +3227,7 @@ static void flush_port(Port *p)
     if (p->drv_ptr->flush != NULL) {
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(driver_flush)) {
-            DTRACE_FORMAT_COMMON_PID_AND_PORT(p->connected, p)
+            DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(p), p)
             DTRACE3(driver_flush, process_str, port_str, p->name);
         }
 #endif
@@ -1935,11 +3242,12 @@ static void flush_port(Port *p)
 	}
 #ifdef ERTS_SMP
 	if (p->xports)
-	    erts_smp_xports_unlock(p);
+	    erts_port_handle_xports(p);
 	ASSERT(!p->xports);
 #endif
     }
-    if ((p->status & ERTS_PORT_SFLGS_DEAD) == 0 && is_port_ioq_empty(p)) {
+    if ((erts_atomic32_read_nob(&p->state) & ERTS_PORT_SFLGS_DEAD) == 0
+	&& is_port_ioq_empty(p)) {
 	terminate_port(p);
     }
 }
@@ -1951,29 +3259,29 @@ terminate_port(Port *prt)
     Eterm send_closed_port_id;
     Eterm connected_id = NIL /* Initialize to silence compiler */;
     erts_driver_t *drv;
-    int halt;
+    erts_aint32_t state;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    ASSERT(!prt->nlinks);
-    ASSERT(!prt->monitors);
+    ASSERT(!ERTS_P_LINKS(prt));
+    ASSERT(!ERTS_P_MONITORS(prt));
 
-    /* prt->status may be altered by kill_port()below */
-    halt = (prt->status & ERTS_PORT_SFLG_HALT) != 0;
-    if (prt->status & ERTS_PORT_SFLG_SEND_CLOSED) {
-	erts_port_status_band_set(prt, ~ERTS_PORT_SFLG_SEND_CLOSED);
-	send_closed_port_id = prt->id;
-	connected_id = prt->connected;
+    /* state may be altered by kill_port() below */
+    state = erts_atomic32_read_band_nob(&prt->state,
+					~ERTS_PORT_SFLG_SEND_CLOSED);
+    if (state & ERTS_PORT_SFLG_SEND_CLOSED) {
+	send_closed_port_id = prt->common.id;
+	connected_id = ERTS_PORT_GET_CONNECTED(prt);
     }
     else {
 	send_closed_port_id = NIL;
     }
 
 #ifdef ERTS_SMP
-    erts_cancel_smp_ptimer(prt->ptimer);
+    erts_cancel_smp_ptimer(prt->common.u.alive.ptimer);
 #else
-    erts_cancel_timer(&prt->tm);
+    erts_cancel_timer(&prt->common.u.alive.tm);
 #endif
 
     drv = prt->drv_ptr;
@@ -1981,7 +3289,7 @@ terminate_port(Port *prt)
 	int fpe_was_unmasked = erts_block_fpe();
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(driver_stop)) {
-            DTRACE_FORMAT_COMMON_PID_AND_PORT(prt->connected, prt)
+            DTRACE_FORMAT_COMMON_PID_AND_PORT(connected_id, prt)
             DTRACE3(driver_stop, process_str, drv->name, port_str);
         }
 #endif
@@ -1989,14 +3297,14 @@ terminate_port(Port *prt)
 	erts_unblock_fpe(fpe_was_unmasked);
 #ifdef ERTS_SMP
 	if (prt->xports)
-	    erts_smp_xports_unlock(prt);
+	    erts_port_handle_xports(prt);
 	ASSERT(!prt->xports);
 #endif
     }
     if(drv->handle != NULL) {
-	erts_smp_mtx_lock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rlock(&erts_driver_list_lock);
 	erts_ddll_decrement_port_count(drv->handle); 
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_runlock(&erts_driver_list_lock);
     }
     stopq(prt);        /* clear queue memory */
     if(prt->linebuf != NULL){
@@ -2012,20 +3320,21 @@ terminate_port(Port *prt)
     if (prt->psd)
 	erts_free(ERTS_ALC_T_PRTSD, prt->psd);
 
+    ASSERT(prt->dist_entry == NULL);
+
     kill_port(prt);
 
     /*
      * We don't want to send the closed message until after the
      * port has been removed from the port table (in kill_port()).
      */
-    if (halt && (erts_smp_atomic32_dec_read_nob(&erts_halt_progress) == 0)) {
-	erts_smp_port_unlock(prt); /* We will exit and never return */
+    if ((state & ERTS_PORT_SFLG_HALT)
+	&& (erts_smp_atomic32_dec_read_nob(&erts_halt_progress) == 0)) {
+	erts_port_release(prt); /* We will exit and never return */
 	erl_exit_flush_async(erts_halt_code, "");
     }
     if (is_internal_port(send_closed_port_id))
 	deliver_result(send_closed_port_id, connected_id, am_closed);
-
-    ASSERT(prt->dist_entry == NULL);
 }
 
 void
@@ -2045,7 +3354,7 @@ static void sweep_one_monitor(ErtsMonitor *mon, void *vpsc)
     if (!rp) {
 	goto done;
     }
-    rmon = erts_remove_monitor(&(rp->monitors),mon->ref);
+    rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
     erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
     if (rmon == NULL) {
 	goto done;
@@ -2099,7 +3408,7 @@ static void sweep_one_link(ErtsLink *lnk, void *vpsc)
 	ASSERT(is_internal_pid(lnk->pid));
 	rp = erts_pid2proc(NULL, 0, lnk->pid, rp_locks);
 	if (rp) {
-	    ErtsLink *rlnk = erts_remove_link(&(rp->nlinks), psc->port);
+	    ErtsLink *rlnk = erts_remove_link(&ERTS_P_LINKS(rp), psc->port);
 
 	    if (rlnk) {
 		int xres = erts_send_exit_signal(NULL,
@@ -2135,11 +3444,13 @@ static void sweep_one_link(ErtsLink *lnk, void *vpsc)
  * that is to kill a port till reason kill. Then the port is stopped.
  * 
  */
-void
-erts_do_exit_port(Port *p, Eterm from, Eterm reason)
+
+int
+erts_deliver_port_exit(Port *p, Eterm from, Eterm reason, int send_closed)
 {
    ErtsLink *lnk;
    Eterm rreason;
+   erts_aint32_t state;
 
    ERTS_SMP_CHK_NO_PROC_LOCKS;
    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p));
@@ -2159,66 +3470,76 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason)
    }
 #endif
 
-   if ((p->status & (ERTS_PORT_SFLGS_DEAD
-		     | ERTS_PORT_SFLG_EXITING
-		     | ERTS_PORT_SFLG_IMMORTAL))
-       || ((reason == am_normal) &&
-	   ((from != p->connected) && (from != p->id)))) {
-      return;
-   }
+   state = erts_atomic32_read_nob(&p->state);
+   if (state & (ERTS_PORT_SFLGS_DEAD
+		| ERTS_PORT_SFLG_EXITING
+		| ERTS_PORT_SFLG_CLOSING))
+       return 0;
+
+   if (reason == am_normal && from != ERTS_PORT_GET_CONNECTED(p) && from != p->common.id)
+       return 0;
+
+   if (send_closed)
+       erts_atomic32_read_bor_relb(&p->state,
+				   ERTS_PORT_SFLG_SEND_CLOSED);
 
    if (IS_TRACED_FL(p, F_TRACE_PORTS)) {
    	trace_port(p, am_closed, reason);
    }
 
-   erts_trace_check_exiting(p->id);
+   erts_trace_check_exiting(p->common.id);
 
    /*
     * Setting the port to not busy here, frees the list of pending
     * processes and makes them runnable.
     */
-   set_busy_port((ErlDrvPort)internal_port_index(p->id), 0);
+   set_busy_port((ErlDrvPort) p, 0);
 
-   if (p->reg != NULL)
-       (void) erts_unregister_name(NULL, 0, p, p->reg->name);
+   if (p->common.u.alive.reg != NULL)
+       (void) erts_unregister_name(NULL, 0, p, p->common.u.alive.reg->name);
 
-   erts_port_status_bor_set(p, ERTS_PORT_SFLG_EXITING);
+   state = erts_atomic32_read_bor_relb(&p->state, ERTS_PORT_SFLG_EXITING);
 
    {
-       SweepContext sc = {p->id, rreason};
-       lnk = p->nlinks;
-       p->nlinks = NULL;
+       SweepContext sc = {p->common.id, rreason};
+       lnk = ERTS_P_LINKS(p);
+       ERTS_P_LINKS(p) = NULL;
        erts_sweep_links(lnk, &sweep_one_link, &sc);
    }
    DRV_MONITOR_LOCK_PDL(p);
    {
-       ErtsMonitor *moni = p->monitors;
-       p->monitors = NULL;
+       ErtsMonitor *moni = ERTS_P_MONITORS(p);
+       ERTS_P_MONITORS(p) = NULL;
        erts_sweep_monitors(moni, &sweep_one_monitor, NULL);
    } 
    DRV_MONITOR_UNLOCK_PDL(p);
 
-   if ((p->status & ERTS_PORT_SFLG_DISTRIBUTION) && p->dist_entry) {
+   if ((state & ERTS_PORT_SFLG_DISTRIBUTION) && p->dist_entry) {
        erts_do_net_exits(p->dist_entry, rreason);
        erts_deref_dist_entry(p->dist_entry); 
-       p->dist_entry = NULL; 
-       erts_port_status_band_set(p, ~ERTS_PORT_SFLG_DISTRIBUTION);
+       p->dist_entry = NULL;
+       erts_atomic32_read_band_relb(&p->state,
+				    ~ERTS_PORT_SFLG_DISTRIBUTION);
    }
        
    if ((reason != am_kill) && !is_port_ioq_empty(p)) {
-       erts_port_status_bandor_set(p,
-				   ~ERTS_PORT_SFLG_EXITING, /* must turn it off */
-				   ERTS_PORT_SFLG_CLOSING);
+       /* must turn exiting flag off */
+       erts_atomic32_read_bset_relb(&p->state,
+				    (ERTS_PORT_SFLG_EXITING
+				     | ERTS_PORT_SFLG_CLOSING),
+				    ERTS_PORT_SFLG_CLOSING);
       flush_port(p);
    }
    else {
        terminate_port(p);
    }
+
+   return 1;
 }
 
 /* About the states ERTS_PORT_SFLG_EXITING and ERTS_PORT_SFLG_CLOSING used above.
 **
-** ERTS_PORT_SFLG_EXITING is a recursion protection for erts_do_exit_port().
+** ERTS_PORT_SFLG_EXITING is a recursion protection for erts_deliver_port_exit().
 ** It is unclear  whether this state is necessary or not, it might be possible
 ** to merge it with ERTS_PORT_SFLG_CLOSING. ERTS_PORT_SFLG_EXITING only persists
 ** over a section of sequential (but highly recursive) code.
@@ -2234,232 +3555,1108 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason)
 **   {PID, close}
 **   {PID, {command, io-list}}
 **   {PID, {connect, New_PID}}
-**
-**
 */
-void erts_port_command(Process *proc,
-		       Eterm caller_id,
-		       Port *port,
-		       Eterm command)
+ErtsPortOpResult
+erts_port_command(Process *c_p,
+		  int flags,
+		  Port *port,
+		  Eterm command,
+		  Eterm *refp)
 {
     Eterm *tp;
-    Eterm pid;
 
-    if (!port)
-	return;
+    ASSERT(port);
 
-    erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_MAIN);
-    ERTS_SMP_CHK_NO_PROC_LOCKS;
-    ASSERT(!INVALID_PORT(port, port->id));
+    flags |= ERTS_PORT_SIG_FLG_BANG_OP;
 
     if (is_tuple_arity(command, 2)) {
+	Eterm cntd;
 	tp = tuple_val(command);
-	if ((pid = port->connected) == tp[1]) {
-	    /* PID must be connected */
+	cntd = tp[1];
+	if (is_internal_pid(cntd)) {
 	    if (tp[2] == am_close) {
-		erts_port_status_bor_set(port, ERTS_PORT_SFLG_SEND_CLOSED);
-		erts_do_exit_port(port, pid, am_normal);
-
-#ifdef USE_VM_PROBES
-		if(DTRACE_ENABLED(port_command)) {
-                    DTRACE_FORMAT_COMMON_PROC_AND_PORT(proc, port)
-		    DTRACE4(port_command, process_str, port_str, port->name, "close");
-		}
-#endif
-		goto done;
+		if (!erts_port_synchronous_ops)
+		    refp = NULL;
+		flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
+		return erts_port_exit(c_p, flags, port, cntd, am_normal, refp);
 	    } else if (is_tuple_arity(tp[2], 2)) {
 		tp = tuple_val(tp[2]);
 		if (tp[1] == am_command) {
-		    if (erts_write_to_port(caller_id, port, tp[2]) == 0)
-			goto done;
-		} else if ((tp[1] == am_connect) && is_internal_pid(tp[2])) {
-#ifdef USE_VM_PROBES
-		    if(DTRACE_ENABLED(port_command)) {
-                        DTRACE_FORMAT_COMMON_PROC_AND_PORT(proc, port)
-			DTRACE4(port_command, process_str, port_str, port->name, "connect");
-		    }
-#endif
-		    port->connected = tp[2];
-		    deliver_result(port->id, pid, am_connected);
-		    goto done;
+		    if (!(flags & ERTS_PORT_SIG_FLG_NOSUSPEND)
+			&& !erts_port_synchronous_ops)
+			refp = NULL;
+		    return erts_port_output(c_p, flags, port, cntd, tp[2], refp);
+		}
+		else if (tp[1] == am_connect) {
+		    if (!erts_port_synchronous_ops)
+			refp = NULL;
+		    flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
+		    return erts_port_connect(c_p, flags, port, cntd, tp[2], refp);
 		}
 	    }
 	}
     }
 
-    {
-	ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
-	Process* rp = erts_pid2proc(NULL, 0,
-				    port->connected, rp_locks);
-	if (rp) {
-	    (void) erts_send_exit_signal(NULL,
-					 port->id,
-					 rp,
-					 &rp_locks, 
-					 am_badsig,
-					 NIL,
-					 NULL,
-					 0);
-	    erts_smp_proc_unlock(rp, rp_locks);
-	}
+    /* badsig */
+    if (!erts_port_synchronous_ops)
+	refp = NULL;
+    flags &= ~ERTS_PORT_SIG_FLG_NOSUSPEND;
+    return bad_port_signal(c_p, flags, port, c_p->common.id, refp, am_command);
+}
+
+static ERTS_INLINE ErtsPortOpResult
+call_driver_control(Eterm caller,
+		    Port *prt,
+		    unsigned int command,
+		    char *bufp,
+		    ErlDrvSizeT size,
+		    char **resp_bufp,
+		    ErlDrvSizeT *from_size)
+{
+    ErlDrvSSizeT cres;
+
+    if (!prt->drv_ptr->control)
+	return ERTS_PORT_OP_BADARG;
 
+
+#ifdef USE_VM_PROBES
+    if (DTRACE_ENABLED(port_control) || DTRACE_ENABLED(driver_control)) {
+        DTRACE_FORMAT_COMMON_PID_AND_PORT(caller, prt);
+        DTRACE4(port_control, process_str, port_str, prt->name, command);
+        DTRACE5(driver_control, process_str, port_str, prt->name,
+                command, size);
     }
- done:
-    erts_smp_proc_lock(proc, ERTS_PROC_LOCK_MAIN);
+#endif
+
+    prt->caller = caller;
+    cres = prt->drv_ptr->control((ErlDrvData) prt->drv_data,
+				 command,
+				 bufp,
+				 size,
+				 resp_bufp,
+				 *from_size);
+    prt->caller = NIL;
+
+    if (cres < 0)
+	return ERTS_PORT_OP_BADARG;
+
+    *from_size = (ErlDrvSizeT) cres;
+
+    return ERTS_PORT_OP_DONE;
 }
 
-/*
- * Control a port synchronously. 
- * Returns either a list or a binary.
- */
-Eterm
-erts_port_control(Process* p, Port* prt, Uint command, Eterm iolist)
-{
-    byte* to_port = NULL;	/* Buffer to write to port. */
-				/* Initialization is for shutting up
-				   warning about use before set. */
-    Uint to_len = 0;		/* Length of buffer. */
-    int must_free = 0;		/* True if the buffer should be freed. */
-    char port_result[ERL_ONHEAP_BIN_LIMIT];  /* Default buffer for result from port. */
-    char* port_resp;		/* Pointer to result buffer. */
-    ErlDrvSSizeT n;
-    ErlDrvSSizeT (*control)
-	(ErlDrvData, unsigned, char*, ErlDrvSizeT, char**, ErlDrvSizeT);
-    int fpe_was_unmasked;
+static void
+cleanup_scheduled_control(Binary *binp, char *bufp)
+{
+    if (binp) {
+	if (erts_refc_dectest(&binp->refc, 0) == 0)
+	    erts_bin_free(binp);
+    }
+    else {
+	if (bufp)
+	    erts_free(ERTS_ALC_T_DRV_CTRL_DATA, bufp);
+    }
+}
 
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    if ((control = prt->drv_ptr->control) == NULL) {
-	return THE_NON_VALUE;
+static ERTS_INLINE Uint
+port_control_result_size(int control_flags,
+			 char *resp_bufp,
+			 ErlDrvSizeT *resp_size,
+			 char *pre_alloc_buf)
+{
+    if (!resp_bufp)
+	return (Uint) 0;
+
+    if (control_flags & PORT_CONTROL_FLAG_BINARY) {
+	if (resp_bufp != pre_alloc_buf) {
+	    ErlDrvBinary *dbin = (ErlDrvBinary *) resp_bufp;
+	    *resp_size = dbin->orig_size;
+	    if (*resp_size > ERL_ONHEAP_BIN_LIMIT)
+		return PROC_BIN_SIZE;
+	}
+	ASSERT(*resp_size <= ERL_ONHEAP_BIN_LIMIT);
+	return (Uint) heap_bin_size((*resp_size));
     }
 
-    /*
-     * Convert the iolist to a buffer, pointed to by to_port,
-     * and with its length in to_len.
-     */
-    if (is_binary(iolist) && binary_bitoffset(iolist) == 0) {
+    return (Uint) 2*(*resp_size);
+}
+
+static ERTS_INLINE Eterm
+write_port_control_result(int control_flags,
+			  char *resp_bufp,
+			  ErlDrvSizeT resp_size,
+			  char *pre_alloc_buf,
+			  Eterm **hpp,
+			  ErlHeapFragment *bp,
+			  ErlOffHeap *ohp)
+{
+    Eterm res;
+    if (!resp_bufp)
+	return NIL;
+    if (control_flags & PORT_CONTROL_FLAG_BINARY) {
+	/* Binary result */
+	ErlDrvBinary *dbin;
+	ErlHeapBin *hbin;
+
+	if (resp_bufp == pre_alloc_buf)
+	    dbin = NULL;
+	else {
+	    dbin = (ErlDrvBinary *) resp_bufp;
+	    if (dbin->orig_size > ERL_ONHEAP_BIN_LIMIT) {
+		ProcBin* pb = (ProcBin *) *hpp;
+		*hpp += PROC_BIN_SIZE;
+		pb->thing_word = HEADER_PROC_BIN;
+		pb->size = dbin->orig_size;
+		pb->next = ohp->first;
+		ohp->first = (struct erl_off_heap_header *) pb;
+		pb->val = ErlDrvBinary2Binary(dbin);
+		pb->bytes = (byte*) dbin->orig_bytes;
+		pb->flags = 0;
+		OH_OVERHEAD(ohp, dbin->orig_size / sizeof(Eterm));
+		return make_binary(pb);
+	    }
+	    resp_bufp = dbin->orig_bytes;
+	    resp_size = dbin->orig_size;
+	}
+
+	hbin = (ErlHeapBin *) *hpp;
+	*hpp += heap_bin_size(resp_size);
+	ASSERT(resp_size <= ERL_ONHEAP_BIN_LIMIT);
+	hbin->thing_word = header_heap_bin(resp_size);
+	hbin->size = resp_size;
+	sys_memcpy(hbin->data, resp_bufp, resp_size);
+	if (dbin)
+	    driver_free_binary(dbin);
+	return make_binary(hbin);
+    }
+
+    /* List result */
+    res = buf_to_intlist(hpp, resp_bufp, resp_size, NIL);
+    if (resp_bufp != pre_alloc_buf)
+	driver_free(resp_bufp);
+    return res;
+}
+
+static int
+port_sig_control(Port *prt,
+		 erts_aint32_t state,
+		 int op,
+		 ErtsProc2PortSigData *sigdp)
+{
+    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
+
+    if (op == ERTS_PROC2PORT_SIG_EXEC) {
+	char resp_buf[ERL_ONHEAP_BIN_LIMIT];
+	ErlDrvSizeT resp_size = sizeof(resp_buf);
+	char *resp_bufp = &resp_buf[0];
+	ErtsPortOpResult res;
+
+	res = call_driver_control(sigdp->caller,
+				  prt,
+				  sigdp->u.control.command,
+				  sigdp->u.control.bufp,
+				  sigdp->u.control.size,
+				  &resp_bufp,
+				  &resp_size);
+
+	if (res == ERTS_PORT_OP_DONE) {
+	    Eterm msg;
+	    Eterm *hp, *hp_start;
+	    ErlHeapFragment *bp;
+	    ErlOffHeap *ohp;
+	    Process *rp;
+	    ErtsProcLocks rp_locks = 0;
+	    Uint hsz;
+	    int control_flags;
+
+	    rp = erts_proc_lookup_raw(sigdp->caller);
+	    if (!rp)
+		goto done;
+
+	    control_flags = prt->control_flags;
+
+	    hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
+	    hsz += port_control_result_size(control_flags,
+					    resp_bufp,
+					    &resp_size,
+					    &resp_buf[0]);
+
+	    hp_start = hp = erts_alloc_message_heap(hsz,
+						    &bp,
+						    &ohp,
+						    rp,
+						    &rp_locks);
+
+	    msg = write_port_control_result(control_flags,
+					    resp_bufp,
+					    resp_size,
+					    &resp_buf[0],
+					    &hp,
+					    bp,
+					    ohp);
+
+	    queue_port_sched_op_reply(rp,
+				      &rp_locks,
+				      hp_start,
+				      hp,
+				      hsz,
+				      bp,
+				      sigdp->ref,
+				      msg);
+
+	    if (rp_locks)
+		erts_smp_proc_unlock(rp, rp_locks);
+	    goto done;
+	}
+    }
+
+    /* failure */
+
+    port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg);
+
+done:
+
+    cleanup_scheduled_control(sigdp->u.control.binp,
+			      sigdp->u.control.bufp);
+
+    return ERTS_PORT_REDS_CONTROL;
+}
+
+
+ErtsPortOpResult
+erts_port_control(Process* c_p,
+		  Port *prt,
+		  unsigned int command,
+		  Eterm data,
+		  Eterm *retvalp)
+{
+    ErtsPortOpResult res;
+    char *bufp = NULL;
+    ErlDrvSizeT size = 0;
+    int try_call;
+    int tmp_alloced = 0;
+    erts_aint32_t sched_flags;
+    Binary *binp;
+    int copy;
+    ErtsProc2PortSigData *sigdp;
+
+    sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+    if (sched_flags & ERTS_PTS_FLG_EXIT)
+	return ERTS_PORT_OP_BADARG;
+
+    try_call = !(sched_flags & ERTS_PTS_FLGS_FORCE_SCHEDULE_OP);
+
+    if (is_binary(data) && binary_bitoffset(data) == 0) {
+	byte *bytep;
 	ERTS_DECLARE_DUMMY(Uint bitoffs);
 	ERTS_DECLARE_DUMMY(Uint bitsize);
-	ERTS_GET_BINARY_BYTES(iolist, to_port, bitoffs, bitsize);
-	to_len = binary_size(iolist);
+	ERTS_GET_BINARY_BYTES(data, bytep, bitoffs, bitsize);
+	bufp = (char *) bytep;
+	size = binary_size(data);
     } else {
 	int r;
 
-	/* Try with an 8KB buffer first (will often be enough I guess). */
-	to_len = 8*1024;
-	to_port = erts_alloc(ERTS_ALC_T_TMP, to_len);
-	must_free = 1;
+	if (!try_call) {
+	    if (erts_iolist_size(data, &size))
+		return ERTS_PORT_OP_BADARG;
+	    bufp = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, size);
+	    r = erts_iolist_to_buf(data, bufp, size);
+	    ASSERT(r == 0);
+	}
+	else {
+	    /* Try with an 8KB buffer first (will often be enough I guess). */
+	    size = 8*1024;
+	    bufp = erts_alloc(ERTS_ALC_T_TMP, size);
+	    tmp_alloced = 1;
+
+	    r = erts_iolist_to_buf(data, bufp, size);
+	    if (ERTS_IOLIST_TO_BUF_SUCCEEDED(r)) {
+		size -= r;
+	    } else {
+		if (r == ERTS_IOLIST_TO_BUF_TYPE_ERROR) { /* Type error */
+		    erts_free(ERTS_ALC_T_TMP, bufp);
+		    return ERTS_PORT_OP_BADARG;
+		}
+		else {
+		    ASSERT(r == ERTS_IOLIST_TO_BUF_OVERFLOW); /* Overflow */
+		    erts_free(ERTS_ALC_T_TMP, bufp);
+		    if (erts_iolist_size(data, &size))
+			return ERTS_PORT_OP_BADARG; /* Type error */
+		}
+		bufp = erts_alloc(ERTS_ALC_T_TMP, size);
+		r = erts_iolist_to_buf(data, bufp, size);
+		ASSERT(r == 0);
+	    }
+	}
+    }
 
-	/*
-	 * In versions before R10B, we used to reserve random
-	 * amounts of extra memory. From R10B, we allocate the
-	 * exact amount.
-	 */
-	r = io_list_to_buf(iolist, (char*) to_port, to_len);
-	if (r >= 0) {
-	    to_len -= r;
-	} else if (r == -2) {	/* Type error */
-	    erts_free(ERTS_ALC_T_TMP, (void *) to_port);
-	    return THE_NON_VALUE;
-	} else {
-	    ASSERT(r == -1);	/* Overflow */
-	    erts_free(ERTS_ALC_T_TMP, (void *) to_port);
-	    if (erts_iolist_size(iolist, &to_len)) { /* Type error */
-		return THE_NON_VALUE;
+    if (try_call) {
+	char resp_buf[ERL_ONHEAP_BIN_LIMIT];
+	char* resp_bufp = &resp_buf[0];
+	ErlDrvSizeT resp_size = sizeof(resp_buf);
+	ErtsTryImmDrvCallResult try_call_res;
+	ErtsTryImmDrvCallState try_call_state
+	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+		c_p,
+		prt,
+		ERTS_PORT_SFLGS_INVALID_LOOKUP,
+		0,
+		0,
+		am_control);
+
+	try_call_res = try_imm_drv_call(&try_call_state);
+	switch (try_call_res) {
+	case ERTS_TRY_IMM_DRV_CALL_OK: {
+	    Eterm *hp;
+	    Uint hsz;
+	    int control_flags;
+
+	    res = call_driver_control(c_p->common.id,
+				      prt,
+				      command,
+				      bufp,
+				      size,
+				      &resp_bufp,
+				      &resp_size);
+	    finalize_imm_drv_call(&try_call_state);
+	    if (tmp_alloced)
+		erts_free(ERTS_ALC_T_TMP, bufp);
+	    if (res == ERTS_PORT_OP_BADARG) {
+		return ERTS_PORT_OP_BADARG;
 	    }
-	    must_free = 1;
-	    to_port = erts_alloc(ERTS_ALC_T_TMP, to_len);
-	    r = io_list_to_buf(iolist, (char*) to_port, to_len);
-	    ASSERT(r == 0);
+
+	    control_flags = prt->control_flags;
+
+	    hsz = port_control_result_size(control_flags,
+					   resp_bufp,
+					   &resp_size,
+					   &resp_buf[0]);
+	    hp = HAlloc(c_p, hsz);
+	    *retvalp = write_port_control_result(control_flags,
+						 resp_bufp,
+						 resp_size,
+						 &resp_buf[0],
+						 &hp,
+						 NULL,
+						 &c_p->off_heap);
+	    return ERTS_PORT_OP_DONE;
+	}
+	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	    if (tmp_alloced)
+		erts_free(ERTS_ALC_T_TMP, bufp);
+	    return ERTS_PORT_OP_BADARG;
+	default:
+	    /* Schedule control() call instead... */
+	    break;
 	}
     }
 
-    prt->caller = p->id;	/* Internal pid */
+    /* Convert data into something that can be scheduled */
 
-    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
-    ERTS_SMP_CHK_NO_PROC_LOCKS;
+    copy = tmp_alloced;
+
+    binp = NULL;
+
+    if (is_binary(data) && binary_bitoffset(data) == 0) {
+	Eterm *ebinp = binary_val_rel(data, NULL);
+	ASSERT(!tmp_alloced);
+	if (*ebinp == HEADER_SUB_BIN)
+	    ebinp = binary_val_rel(((ErlSubBin *) ebinp)->orig, NULL);
+	if (*ebinp != HEADER_PROC_BIN)
+	    copy = 1;
+	else {
+	    binp = ((ProcBin *) ebinp)->val;
+	    ASSERT(bufp < bufp + size);
+	    ASSERT(binp->orig_bytes <= bufp
+		   && bufp + size <= binp->orig_bytes + binp->orig_size);
+	    erts_refc_inc(&binp->refc, 1);
+	}
+    }
+
+    if (copy) {
+	char *old_bufp = bufp;
+	bufp = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, size);
+	sys_memcpy(bufp, old_bufp, size);
+	if (tmp_alloced)
+	    erts_free(ERTS_ALC_T_TMP, old_bufp);
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_CONTROL;
+    sigdp->u.control.binp = binp;
+    sigdp->u.control.command = command;
+    sigdp->u.control.bufp = bufp;
+    sigdp->u.control.size = size;
+    
+    res = erts_schedule_proc2port_signal(c_p,
+					 prt,
+					 c_p->common.id,
+					 retvalp,
+					 sigdp,
+					 0,
+					 port_sig_control);
+    if (res != ERTS_PORT_OP_SCHEDULED) {
+	cleanup_scheduled_control(binp, bufp);
+	return ERTS_PORT_OP_BADARG;
+    }
+    return res;
+}
+
+static ERTS_INLINE ErtsPortOpResult
+call_driver_call(Eterm caller,
+		 Port *prt,
+		 unsigned int command,
+		 char *bufp,
+		 ErlDrvSizeT size,
+		 char **resp_bufp,
+		 ErlDrvSizeT *from_size,
+		 unsigned *ret_flagsp)
+{
+    ErlDrvSSizeT cres;
+
+    if (!prt->drv_ptr->call)
+	return ERTS_PORT_OP_BADARG;
 
 #ifdef USE_VM_PROBES
-    if (DTRACE_ENABLED(port_control) || DTRACE_ENABLED(driver_control)) {
-        DTRACE_FORMAT_COMMON_PROC_AND_PORT(p, prt);
-        DTRACE4(port_control, process_str, port_str, prt->name, command);
-        DTRACE5(driver_control, process_str, port_str, prt->name,
-                command, to_len);
+    if (DTRACE_ENABLED(driver_call)) {
+        DTRACE_CHARBUF(process_str, DTRACE_TERM_BUF_SIZE);
+        DTRACE_CHARBUF(port_str, DTRACE_TERM_BUF_SIZE);
+
+        dtrace_pid_str(caller, process_str);
+        dtrace_port_str(prt, port_str);
+        DTRACE5(driver_call, process_str, port_str, prt->name, command, size);
     }
 #endif
 
-    /*
-     * Call the port's control routine.
-     */
+    prt->caller = caller;
+    cres = prt->drv_ptr->call((ErlDrvData) prt->drv_data,
+			      command,
+			      bufp,
+			      size,
+			      resp_bufp,
+			      *from_size,
+			      ret_flagsp);
+    prt->caller = NIL;
 
-    port_resp = port_result;
-    fpe_was_unmasked = erts_block_fpe();
-    n = control((ErlDrvData)prt->drv_data, command, (char*)to_port, to_len,
-		&port_resp, sizeof(port_result));
-    erts_unblock_fpe(fpe_was_unmasked);
-    if (must_free) {
-	erts_free(ERTS_ALC_T_TMP, (void *) to_port);
+    if (cres <= 0
+	|| ((byte) (*resp_bufp)[0]) != VERSION_MAGIC)
+	return ERTS_PORT_OP_BADARG;
+
+    *from_size = (ErlDrvSizeT) cres;
+
+    return ERTS_PORT_OP_DONE;
+}
+
+
+static
+void cleanup_scheduled_call(char *bufp)
+{
+    if (bufp)
+	erts_free(ERTS_ALC_T_DRV_CALL_DATA, bufp);
+}
+
+static int
+port_sig_call(Port *prt,
+	      erts_aint32_t state,
+	      int op,
+	      ErtsProc2PortSigData *sigdp)
+{
+    char resp_buf[256];
+    ErlDrvSizeT resp_size = sizeof(resp_buf);
+    char *resp_bufp = &resp_buf[0];
+    unsigned ret_flags = 0U;
+
+
+    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
+
+    if (op == ERTS_PROC2PORT_SIG_EXEC) {
+	ErtsPortOpResult res;
+
+	res = call_driver_call(sigdp->caller,
+			       prt,
+			       sigdp->u.call.command,
+			       sigdp->u.call.bufp,
+			       sigdp->u.call.size,
+			       &resp_bufp,
+			       &resp_size,
+			       &ret_flags);
+
+	if (res == ERTS_PORT_OP_DONE) {
+	    Eterm msg;
+	    Eterm *hp;
+	    ErlHeapFragment *bp;
+	    ErlOffHeap *ohp;
+	    Process *rp;
+	    ErtsProcLocks rp_locks = 0;
+	    Uint hsz;
+
+	    rp = erts_proc_lookup_raw(sigdp->caller);
+	    if (!rp)
+		goto done;
+
+	    hsz = erts_decode_ext_size((byte *) resp_bufp, resp_size);
+	    if (hsz >= 0) {
+		Eterm *hp_start;
+		byte *endp;
+
+		hsz += 3; /* ok tuple */
+		hsz += ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
+
+		hp_start = hp = erts_alloc_message_heap(hsz,
+							&bp,
+							&ohp,
+							rp,
+							&rp_locks);
+		endp = (byte *) resp_bufp;
+		msg = erts_decode_ext(&hp, ohp, &endp);
+		if (is_value(msg)) {
+		    msg = TUPLE2(hp, am_ok, msg);
+		    hp += 3;
+
+		    queue_port_sched_op_reply(rp,
+					      &rp_locks,
+					      hp_start,
+					      hp,
+					      hsz,
+					      bp,
+					      sigdp->ref,
+					      msg);
+
+		    if (rp_locks)
+			erts_smp_proc_unlock(rp, rp_locks);
+		    goto done;
+		}
+		if (bp)
+		    free_message_buffer(bp);
+		if (rp_locks)
+		    erts_smp_proc_unlock(rp, rp_locks);
+	    }
+	}
     }
-    prt->caller = NIL;
-#ifdef ERTS_SMP
-    if (prt->xports)
-	erts_smp_xports_unlock(prt);
-    ASSERT(!prt->xports);
-#endif
 
-    erts_smp_proc_lock(p, ERTS_PROC_LOCK_MAIN);
-    /*
-     * Handle the result.
-     */
+    port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg);
+
+done:
 
-    if (n < 0) {
-	return THE_NON_VALUE;
+    if (resp_bufp != &resp_buf[0] && !(ret_flags & DRIVER_CALL_KEEP_BUFFER))
+	driver_free(resp_bufp);
+
+    cleanup_scheduled_call(sigdp->u.call.bufp);
+
+    return ERTS_PORT_REDS_CALL;
+}
+
+
+ErtsPortOpResult
+erts_port_call(Process* c_p,
+	       Port *prt,
+	       unsigned int command,
+	       Eterm data,
+	       Eterm *retvalp)
+{
+    ErtsPortOpResult res;
+    char input_buf[256];
+    char *bufp;
+    byte *endp;
+    ErlDrvSizeT size;
+    int try_call;
+    erts_aint32_t sched_flags;
+    ErtsProc2PortSigData *sigdp;
+
+    sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
+    if (sched_flags & ERTS_PTS_FLG_EXIT) {
+	return ERTS_PORT_OP_BADARG;
     }
 
-    if ((prt->control_flags & PORT_CONTROL_FLAG_BINARY) == 0) {	/* List result */
-	Eterm ret;	
-	Eterm* hp = HAlloc(p, 2*n);
-	ret = buf_to_intlist(&hp, port_resp, n, NIL);
-	if (port_resp != port_result) {
-	    driver_free(port_resp);
+    try_call = !(sched_flags & ERTS_PTS_FLGS_FORCE_SCHEDULE_OP);
+
+    size = erts_encode_ext_size(data);
+
+    if (!try_call)
+	bufp = erts_alloc(ERTS_ALC_T_DRV_CALL_DATA, size);
+    else if (size <= sizeof(input_buf))
+	bufp = &input_buf[0];
+    else
+	bufp = erts_alloc(ERTS_ALC_T_TMP, size);
+
+    endp = (byte *) bufp;
+    erts_encode_ext(data, &endp);
+
+    if (endp - (byte *) bufp > size)
+	ERTS_INTERNAL_ERROR("erts_internal:port_call() - Buffer overflow");
+
+    size = endp - (byte *) bufp;
+
+    if (try_call) {
+	char resp_buf[255];
+	char* resp_bufp = &resp_buf[0];
+	ErlDrvSizeT resp_size = sizeof(resp_buf);
+	ErtsTryImmDrvCallResult try_call_res;
+	ErtsTryImmDrvCallState try_call_state
+	    = ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+		c_p,
+		prt,
+		ERTS_PORT_SFLGS_INVALID_LOOKUP,
+		0,
+		0,
+		am_call);
+
+	try_call_res = try_imm_drv_call(&try_call_state);
+	switch (try_call_res) {
+	case ERTS_TRY_IMM_DRV_CALL_OK: {
+	    Eterm *hp, *hp_end;
+	    Uint hsz;
+	    unsigned ret_flags = 0U;
+	    Eterm term;
+
+	    res = call_driver_call(c_p->common.id,
+				   prt,
+				   command,
+				   bufp,
+				   size,
+				   &resp_bufp,
+				   &resp_size,
+				   &ret_flags);
+
+	    finalize_imm_drv_call(&try_call_state);
+	    if (bufp != &input_buf[0])
+		erts_free(ERTS_ALC_T_TMP, bufp);
+	    if (res == ERTS_PORT_OP_BADARG)
+		return ERTS_PORT_OP_BADARG;
+	    hsz = erts_decode_ext_size((byte *) resp_bufp, resp_size);
+	    if (hsz < 0)
+		return ERTS_PORT_OP_BADARG;
+	    hsz += 3;
+	    hp = HAlloc(c_p, hsz);
+	    hp_end = hp + hsz;
+	    endp = (byte *) resp_bufp;
+	    term = erts_decode_ext(&hp, &MSO(c_p), &endp);
+	    if (term == THE_NON_VALUE)
+		return ERTS_PORT_OP_BADARG;
+	    *retvalp = TUPLE2(hp, am_ok, term);
+	    hp += 3;
+	    HRelease(c_p, hp_end, hp);
+	    if (resp_buf != &resp_buf[0]
+		&& !(ret_flags & DRIVER_CALL_KEEP_BUFFER))
+		driver_free(resp_buf);
+	    return ERTS_PORT_OP_DONE;
 	}
-	return ret;
-    } 
-    else if (port_resp == NULL) {
-	return NIL;
-    } 
-    else {                   /* Binary result */
-	ErlDrvBinary *dbin;
-	ErlHeapBin *hbin;
-	if (port_resp != port_result) {
-	    dbin = (ErlDrvBinary *) port_resp;
-	    if (dbin->orig_size > ERL_ONHEAP_BIN_LIMIT) {
-		ProcBin* pb = (ProcBin *) HAlloc(p, PROC_BIN_SIZE);
-		pb->thing_word = HEADER_PROC_BIN;
-		pb->size = dbin->orig_size;
-		pb->next = MSO(p).first;
-		MSO(p).first = (struct erl_off_heap_header*)pb;
-		pb->val = ErlDrvBinary2Binary(dbin);
-		pb->bytes = (byte*) dbin->orig_bytes;
-		pb->flags = 0;
-		OH_OVERHEAD(&(MSO(p)), dbin->orig_size / sizeof(Eterm));
-		return make_binary(pb);
-	    }
-	    port_resp = dbin->orig_bytes;
-	    n = dbin->orig_size;
-	} else {
-	    dbin = NULL;
+	case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	    if (bufp != &input_buf[0])
+		erts_free(ERTS_ALC_T_TMP, bufp);
+	    return ERTS_PORT_OP_BADARG;
+	default:
+	    /* Schedule call() call instead... */
+	    break;
 	}
-	hbin = (ErlHeapBin*) HAlloc(p, heap_bin_size(n));
-	ASSERT(n <= ERL_ONHEAP_BIN_LIMIT);
-	hbin->thing_word = header_heap_bin(n);
-	hbin->size = n;
-	sys_memcpy(hbin->data, port_resp, n);
-	if (dbin != NULL) {
-	    driver_free_binary(dbin);
+    }
+
+    /* Convert data into something that can be scheduled */
+
+    if (bufp == &input_buf[0] || try_call) {
+	char *new_bufp = erts_alloc(ERTS_ALC_T_DRV_CALL_DATA, size);
+	sys_memcpy(new_bufp, bufp, size);
+	if (bufp != &input_buf[0])
+	    erts_free(ERTS_ALC_T_TMP, bufp);
+	bufp = new_bufp;
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_CALL;
+    sigdp->u.call.command = command;
+    sigdp->u.call.bufp = bufp;
+    sigdp->u.call.size = size;
+    
+    res = erts_schedule_proc2port_signal(c_p,
+					 prt,
+					 c_p->common.id,
+					 retvalp,
+					 sigdp,
+					 0,
+					 port_sig_call);
+    if (res != ERTS_PORT_OP_SCHEDULED) {
+	cleanup_scheduled_call(bufp);
+	return ERTS_PORT_OP_BADARG;
+    }
+    return res;
+}
+
+static Eterm
+make_port_info_term(Eterm **hpp_start,
+		    Eterm **hpp,
+		    Uint *hszp,
+		    ErlHeapFragment **bpp,
+		    Port *prt,
+		    Eterm item)
+{
+    ErlOffHeap *ohp;
+
+    if (is_value(item)) {
+	if (erts_bld_port_info(NULL, NULL, hszp, prt, item) == am_false)
+	    return THE_NON_VALUE;
+	if (*hszp) {
+	    *bpp = new_message_buffer(*hszp);
+	    *hpp_start = *hpp = (*bpp)->mem;
+	    ohp = &(*bpp)->off_heap;
 	}
-	return make_binary(hbin);
+	else {
+	    *bpp = NULL;
+	    *hpp_start = *hpp = NULL;
+	    ohp = NULL;
+	}
+	return erts_bld_port_info(hpp, ohp, NULL, prt, item);
+    }
+    else {
+	int i;
+	int len;
+	int start;
+	static Eterm item[] = ERTS_PORT_INFO_1_ITEMS;
+	static Eterm value[sizeof(item)/sizeof(item[0])];
+
+	start = 0;
+	len = sizeof(item)/sizeof(item[0]);
+
+	for (i = start; i < sizeof(item)/sizeof(item[0]); i++) {
+	    ASSERT(is_atom(item[i]));
+	    value[i] = erts_bld_port_info(NULL, NULL, hszp, prt, item[i]);
+	}
+
+	if (value[0] == am_undefined) {
+	    start++;
+	    len--;
+	}
+
+	erts_bld_list(NULL, hszp, len, &value[start]);
+
+	*bpp = new_message_buffer(*hszp);
+	*hpp_start = *hpp = (*bpp)->mem;
+	ohp = &(*bpp)->off_heap;
+
+	for (i = start; i < sizeof(item)/sizeof(item[0]); i++)
+	    value[i] = erts_bld_port_info(hpp, ohp, NULL, prt, item[i]);
+
+	return erts_bld_list(hpp, NULL, len, &value[start]);
+    }
+}
+
+static int
+port_sig_info(Port *prt,
+	      erts_aint32_t state,
+	      int op,
+	      ErtsProc2PortSigData *sigdp)
+{
+    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
+    if (op != ERTS_PROC2PORT_SIG_EXEC)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_undefined);
+    else {
+	Eterm *hp, *hp_start;
+	Uint hsz;
+	ErlHeapFragment *bp;
+	Eterm value;
+	Process *rp;
+	ErtsProcLocks rp_locks = 0;
+
+	rp = erts_proc_lookup_raw(sigdp->caller);
+	if (!rp)
+	    return ERTS_PORT_REDS_INFO;
+
+	hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
+	value = make_port_info_term(&hp_start,
+				    &hp,
+				    &hsz,
+				    &bp,
+				    prt,
+				    sigdp->u.info.item);
+	if (is_value(value)) {
+	    queue_port_sched_op_reply(rp,
+				      &rp_locks,
+				      hp_start,
+				      hp,
+				      hsz,
+				      bp,
+				      sigdp->ref,
+				      value);
+	}
+	if (rp_locks)
+	    erts_smp_proc_unlock(rp, rp_locks);
+    }
+    return ERTS_PORT_REDS_INFO;
+}
+
+ErtsPortOpResult
+erts_port_info(Process* c_p,
+	       Port *prt,
+	       Eterm item,
+	       Eterm *retvalp)
+{
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallResult try_call_res;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+	    c_p,
+	    prt,
+	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+	    0,
+	    0,
+	    am_info);
+
+    try_call_res = try_imm_drv_call(&try_call_state);
+    switch (try_call_res) {
+    case ERTS_TRY_IMM_DRV_CALL_OK: {
+	Eterm *hp, *hp_start;
+	ErlHeapFragment *bp;
+	Uint hsz = 0;
+	Eterm value = make_port_info_term(&hp_start, &hp, &hsz, &bp, prt, item);
+	finalize_imm_drv_call(&try_call_state);
+	if (is_non_value(value))
+	    return ERTS_PORT_OP_BADARG;
+	else if (is_immed(value))
+	    *retvalp = value;
+	else {
+	    Uint used_h_size = hp - hp_start;
+	    hp = HAlloc(c_p, used_h_size);
+	    *retvalp = copy_struct(value, used_h_size, &hp, &MSO(c_p));
+	    free_message_buffer(bp);
+	}
+	return ERTS_PORT_OP_DONE;
+    }
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+	/* Schedule call instead... */
+	break;
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_INFO;
+    sigdp->u.info.item = item;
+
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p->common.id,
+					  retvalp,
+					  sigdp,
+					  0,
+					  port_sig_info);
+}
+
+static int
+port_sig_set_data(Port *prt,
+		  erts_aint32_t state,
+		  int op,
+		  ErtsProc2PortSigData *sigdp)
+{
+    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
+
+    if (op == ERTS_PROC2PORT_SIG_EXEC) {
+	if (prt->bp)
+	    free_message_buffer(prt->bp);
+	prt->bp = sigdp->u.set_data.bp;
+	prt->data = sigdp->u.set_data.data;
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_true);
+    }
+    else {
+	if (sigdp->u.set_data.bp)
+	    free_message_buffer(sigdp->u.set_data.bp);
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg);
+    }
+    return ERTS_PORT_REDS_SET_DATA;
+}
+
+ErtsPortOpResult
+erts_port_set_data(Process* c_p,
+		   Port *prt,
+		   Eterm data,
+		   Eterm *refp)
+{
+    ErtsPortOpResult res;
+    Eterm set_data;
+    ErlHeapFragment *bp;
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallResult try_call_res;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+	    c_p,
+	    prt,
+	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+	    0,
+	    !refp,
+	    am_set_data);
+
+    if (is_immed(data)) {
+	set_data = data;
+	bp = NULL;
+    }
+    else {
+	Eterm *hp;
+	Uint sz = size_object(data);
+	bp = new_message_buffer(sz);
+	hp = bp->mem;
+	set_data = copy_struct(data, sz, &hp, &bp->off_heap);
+    }
+
+    try_call_res = try_imm_drv_call(&try_call_state);
+    switch (try_call_res) {
+    case ERTS_TRY_IMM_DRV_CALL_OK:
+	if (prt->bp)
+	    free_message_buffer(prt->bp);
+	prt->bp = bp;
+	prt->data = set_data;
+	finalize_imm_drv_call(&try_call_state);
+	return ERTS_PORT_OP_DONE;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+	/* Schedule call instead... */
+	break;
+    }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_SET_DATA;
+    sigdp->u.set_data.data = set_data;
+    sigdp->u.set_data.bp = bp;
+
+    res = erts_schedule_proc2port_signal(c_p,
+					 prt,
+					 c_p->common.id,
+					 refp,
+					 sigdp,
+					 0,
+					 port_sig_set_data);
+    if (res != ERTS_PORT_OP_SCHEDULED && bp)
+	free_message_buffer(bp);
+    return res;
+}
+
+static int
+port_sig_get_data(Port *prt,
+		  erts_aint32_t state,
+		  int op,
+		  ErtsProc2PortSigData *sigdp)
+{
+    ASSERT(sigdp->flags & ERTS_P2P_SIG_DATA_FLG_REPLY);
+    if (op != ERTS_PROC2PORT_SIG_EXEC)
+	port_sched_op_reply(sigdp->caller, sigdp->ref, am_badarg);
+    else {
+	Process *rp;
+	ErtsProcLocks rp_locks = 0;
+
+	rp = erts_proc_lookup_raw(sigdp->caller);
+	if (rp) {
+	    Uint hsz;
+	    Eterm *hp, *hp_start;
+	    Eterm data, msg;
+	    ErlHeapFragment *bp;
+	    ErlOffHeap *ohp;
+
+	    hsz = ERTS_QUEUE_PORT_SCHED_OP_REPLY_SIZE;
+	    hsz += 3;
+	    if (prt->bp)
+		hsz += prt->bp->used_size;
+
+	    hp_start = hp = erts_alloc_message_heap(hsz,
+						    &bp,
+						    &ohp,
+						    rp,
+						    &rp_locks);
+
+	    if (is_immed(prt->data))
+		data = prt->data;
+	    else
+		data = copy_struct(prt->data,
+				   prt->bp->used_size,
+				   &hp,
+				   &bp->off_heap);
+
+
+
+	    msg = TUPLE2(hp, am_ok, data);
+	    hp += 3;
+
+	    queue_port_sched_op_reply(rp,
+				      &rp_locks,
+				      hp_start,
+				      hp,
+				      hsz,
+				      bp,
+				      sigdp->ref,
+				      msg);
+	    if (rp_locks)
+		erts_smp_proc_unlock(rp, rp_locks);
+	}
+    }
+    return ERTS_PORT_REDS_GET_DATA;
+}
+
+ErtsPortOpResult
+erts_port_get_data(Process* c_p,
+		   Port *prt,
+		   Eterm *retvalp)
+{
+    ErtsProc2PortSigData *sigdp;
+    ErtsTryImmDrvCallResult try_call_res;
+    ErtsTryImmDrvCallState try_call_state
+	= ERTS_INIT_TRY_IMM_DRV_CALL_STATE(
+	    c_p,
+	    prt,
+	    ERTS_PORT_SFLGS_INVALID_LOOKUP,
+	    0,
+	    0,
+	    am_get_data);
+
+    try_call_res = try_imm_drv_call(&try_call_state);
+    switch (try_call_res) {
+    case ERTS_TRY_IMM_DRV_CALL_OK: {
+	Eterm *hp;
+	Eterm data;
+	ErlHeapFragment *bp;
+	Uint sz;
+	if (is_immed(prt->data)) {
+	    bp = NULL;
+	    data = prt->data;
+	}
+	else {
+	    bp = new_message_buffer(prt->bp->used_size);
+	    data = copy_struct(prt->data,
+			       prt->bp->used_size,
+			       &hp,
+			       &bp->off_heap);
+	}	    
+	finalize_imm_drv_call(&try_call_state);
+	if (is_immed(data))
+	    sz = 0;
+	else 
+	    sz = bp->used_size;
+
+	hp = HAlloc(c_p,  sz + 3);
+	if (is_not_immed(data)) {
+	    data = copy_struct(data, bp->used_size, &hp, &MSO(c_p));
+	    free_message_buffer(bp);
+	}
+	*retvalp = TUPLE2(hp, am_ok, data);
+	return ERTS_PORT_OP_DONE;
+    }
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_PORT:
+	return ERTS_PORT_OP_DROPPED;
+    case ERTS_TRY_IMM_DRV_CALL_INVALID_SCHED_FLAGS:
+    case ERTS_TRY_IMM_DRV_CALL_BUSY_LOCK:
+	/* Schedule call instead... */
+	break;
     }
+
+    sigdp = erts_port_task_alloc_p2p_sig_data();
+    sigdp->flags = ERTS_P2P_SIG_TYPE_GET_DATA;
+
+    return erts_schedule_proc2port_signal(c_p,
+					  prt,
+					  c_p->common.id,
+					  retvalp,
+					  sigdp,
+					  0,
+					  port_sig_get_data);
 }
 
 typedef struct {
@@ -2480,39 +4677,39 @@ static void prt_one_lnk(ErtsLink *lnk, void *vprtd)
 }
 
 void
-print_port_info(int to, void *arg, int i)
+print_port_info(Port *p, int to, void *arg)
 {
-    Port* p = &erts_port[i];
+    erts_aint32_t state = erts_atomic32_read_nob(&p->state);
 
-    if (p->status & ERTS_PORT_SFLGS_DEAD)
+    if (state & ERTS_PORT_SFLGS_DEAD)
 	return;
 
-    erts_print(to, arg, "=port:%T\n", p->id);
-    erts_print(to, arg, "Slot: %d\n", i);
-    if (p->status & ERTS_PORT_SFLG_CONNECTED) {
-	erts_print(to, arg, "Connected: %T", p->connected);
+    erts_print(to, arg, "=port:%T\n", p->common.id);
+    erts_print(to, arg, "Slot: %d\n", internal_port_index(p->common.id));
+    if (state & ERTS_PORT_SFLG_CONNECTED) {
+	erts_print(to, arg, "Connected: %T", ERTS_PORT_GET_CONNECTED(p));
 	erts_print(to, arg, "\n");
     }
 
-    if (p->nlinks != NULL) {
+    if (ERTS_P_LINKS(p)) {
 	prt_one_lnk_data prtd;
 	prtd.to = to;
 	prtd.arg = arg;
 	erts_print(to, arg, "Links: ");
-	erts_doforall_links(p->nlinks, &prt_one_lnk, &prtd);
+	erts_doforall_links(ERTS_P_LINKS(p), &prt_one_lnk, &prtd);
 	erts_print(to, arg, "\n");
     }
-    if (p->monitors != NULL) {
+    if (ERTS_P_MONITORS(p)) {
 	prt_one_lnk_data prtd;
 	prtd.to = to;
 	prtd.arg = arg;
 	erts_print(to, arg, "Monitors: ");
-	erts_doforall_monitors(p->monitors, &prt_one_monitor, &prtd);
+	erts_doforall_monitors(ERTS_P_MONITORS(p), &prt_one_monitor, &prtd);
 	erts_print(to, arg, "\n");
     }
 
-    if (p->reg != NULL)
-	erts_print(to, arg, "Registered as: %T\n", p->reg->name);
+    if (p->common.u.alive.reg != NULL)
+	erts_print(to, arg, "Registered as: %T\n", p->common.u.alive.reg->name);
 
     if (p->drv_ptr == &fd_driver) {
 	erts_print(to, arg, "Port is UNIX fd not opened by emulator: %s\n", p->name);
@@ -2526,109 +4723,143 @@ print_port_info(int to, void *arg, int i)
 }
 
 void
-set_busy_port(ErlDrvPort port_num, int on)
+set_busy_port(ErlDrvPort dprt, int on)
 {
+    Port *prt;
+    erts_aint32_t flags;
+
 #ifdef USE_VM_PROBES
     DTRACE_CHARBUF(port_str, 16);
 #endif
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(&erts_port[port_num]));
+    prt = erts_drvport2port_raw(dprt);
+    if (!prt)
+	return;
 
     if (on) {
-        erts_port_status_bor_set(&erts_port[port_num],
-				 ERTS_PORT_SFLG_PORT_BUSY);
+	flags = erts_smp_atomic32_read_bor_acqb(&prt->sched.flags,
+						ERTS_PTS_FLG_BUSY_PORT);
+	if (flags & ERTS_PTS_FLG_BUSY_PORT)
+	    return; /* Already busy */
+
+	if (flags & ERTS_PTS_FLG_HAVE_NS_TASKS)
+	    erts_port_task_abort_nosuspend_tasks(prt);
+
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(port_busy)) {
             erts_snprintf(port_str, sizeof(port_str),
-                          "%T", erts_port[port_num].id);
+                          "%T", prt->common.id);
             DTRACE1(port_busy, port_str);
         }
 #endif
     } else {
-        ErtsProcList* plp = erts_port[port_num].suspended;
-        erts_port_status_band_set(&erts_port[port_num],
-				  ~ERTS_PORT_SFLG_PORT_BUSY);
-        erts_port[port_num].suspended = NULL;
+	flags = erts_smp_atomic32_read_band_acqb(&prt->sched.flags,
+						 ~ERTS_PTS_FLG_BUSY_PORT);
+	if (!(flags & ERTS_PTS_FLG_BUSY_PORT))
+	    return; /* Already non-busy */
 
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(port_not_busy)) {
             erts_snprintf(port_str, sizeof(port_str),
-                          "%T", erts_port[port_num].id);
+                          "%T", prt->common.id);
             DTRACE1(port_not_busy, port_str);
         }
 #endif
-	if (erts_port[port_num].dist_entry) {
+	if (prt->dist_entry) {
 	    /*
 	     * Processes suspended on distribution ports are
 	     * normally queued on the dist entry.
 	     */
-	    erts_dist_port_not_busy(&erts_port[port_num]);
+	    erts_dist_port_not_busy(prt);
 	}
 
-	/*
-	 * Resume, in a round-robin fashion, all processes waiting on the port.
-	 * 
-	 * This version submitted by Tony Rogvall. The earlier version used
-	 * to resume the processes in order, which caused starvation of all but
-	 * the first process.
-	 */
+	if (!(flags & ERTS_PTS_FLG_BUSY_PORT_Q))
+	    erts_port_resume_procs(prt);
+    }
+}
+
+void
+erts_port_resume_procs(Port *prt)
+{
+    /*
+     * Resume, in a round-robin fashion, all processes waiting on the port.
+     * 
+     * This version submitted by Tony Rogvall. The earlier version used
+     * to resume the processes in order, which caused starvation of all but
+     * the first process.
+     */
+    ErtsProcList *plp;
+
+    erts_port_task_sched_lock(&prt->sched);
+    plp = prt->suspended;
+    prt->suspended = NULL;
+    erts_port_task_sched_unlock(&prt->sched);
+
+    if (erts_proclist_fetch(&plp, NULL)) {
 
-        if (plp) {
 #ifdef USE_VM_PROBES
-            /*
-             * Hrm, for blocked dist ports, plp always seems to be NULL.
-             * That's not so fun.
-             * Well, another way to get the same info is using a D
-             * script to correlate an earlier process-port_blocked+pid
-             * event with a later process-scheduled event.  That's
-             * subject to the multi-CPU races with how events are
-             * handled, but hey, that way works most of the time.
-             */
-            if (DTRACE_ENABLED(process_port_unblocked)) {
-                DTRACE_CHARBUF(pid_str, 16);
-                ErtsProcList* plp2 = plp;
-
-                erts_snprintf(port_str, sizeof(port_str),
-                             "%T", erts_port[port_num]);
-                while (plp2 != NULL) {
-                    erts_snprintf(pid_str, sizeof(pid_str), "%T", plp2->pid);
-                    DTRACE2(process_port_unblocked, pid_str, port_str);
-                }
-            }
-#endif
-            /* First proc should be resumed last */
-	    if (plp->next) {
-		erts_resume_processes(plp->next);
-		plp->next = NULL;
+	/*
+	 * Hrm, for blocked dist ports, plp always seems to be NULL.
+	 * That's not so fun.
+	 * Well, another way to get the same info is using a D
+	 * script to correlate an earlier process-port_blocked+pid
+	 * event with a later process-scheduled event.  That's
+	 * subject to the multi-CPU races with how events are
+	 * handled, but hey, that way works most of the time.
+	 */
+	if (DTRACE_ENABLED(process_port_unblocked)) {
+	    DTRACE_CHARBUF(port_str, 16);
+	    DTRACE_CHARBUF(pid_str, 16);
+	    ErtsProcList* plp2 = plp;
+
+	    erts_snprintf(port_str, sizeof(port_str), "%T", prt->common.id);
+	    while (plp2 != NULL) {
+		erts_snprintf(pid_str, sizeof(pid_str), "%T", plp2->pid);
+		DTRACE2(process_port_unblocked, pid_str, port_str);
 	    }
-	    erts_resume_processes(plp);
-        }
+	}
+#endif
+
+	/* First proc should be resumed last */
+	if (plp->next) {
+	    plp->next->prev = NULL;
+	    erts_resume_processes(plp->next);
+	    plp->next = NULL;
+	}
+	erts_resume_processes(plp);
     }
 }
 
 void set_port_control_flags(ErlDrvPort port_num, int flags)
 {
-
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(&erts_port[port_num]));
-
-    erts_port[port_num].control_flags = flags;
+    Port *prt = erts_drvport2port_raw(port_num);
+    if (prt)
+	prt->control_flags = flags;
 }
 
-int get_port_flags(ErlDrvPort ix) { 
-    Port* prt = erts_drvport2port(ix);
+int get_port_flags(ErlDrvPort ix)
+{
+    int flags;
+    Port *prt;
+    erts_aint32_t state;
+
+    prt = erts_drvport2port(ix, &state);
+    if (!prt)
+	return 0;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    if (prt == NULL)
-	return 0;
+    flags = 0;
+    if (state & ERTS_PORT_SFLG_BINARY_IO)
+	flags |= PORT_FLAG_BINARY;
+    if (state & ERTS_PORT_SFLG_LINEBUF_IO)
+	flags |= PORT_FLAG_LINE;
 
-    return (prt->status & ERTS_PORT_SFLG_BINARY_IO ? PORT_FLAG_BINARY : 0) 
-	| (prt->status & ERTS_PORT_SFLG_LINEBUF_IO ? PORT_FLAG_LINE : 0);
+    return flags;
 }
 
-
 void erts_raw_port_command(Port* p, byte* buf, Uint len)
 {
     int fpe_was_unmasked;
@@ -2665,25 +4896,18 @@ int async_ready(Port *p, void* data)
 
     if (p) {
 	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p));
-	ASSERT(!(p->status & ERTS_PORT_SFLGS_DEAD));
 	if (p->drv_ptr->ready_async != NULL) {
 #ifdef USE_VM_PROBES
             if (DTRACE_ENABLED(driver_ready_async)) {
-                DTRACE_FORMAT_COMMON_PID_AND_PORT(p->connected, p)
+                DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(p), p)
                 DTRACE3(driver_ready_async, process_str, port_str, p->name);
             }
 #endif
 	    (*p->drv_ptr->ready_async)((ErlDrvData)p->drv_data, data);
 	    need_free = 0;
-#ifdef ERTS_SMP
-	    if (p->xports)
-		erts_smp_xports_unlock(p);
-	    ASSERT(!p->xports);
-#endif
-	}
-	if ((p->status & ERTS_PORT_SFLG_CLOSING) && is_port_ioq_empty(p)) {
-	    terminate_port(p);
+
 	}
+	erts_port_driver_callback_epilogue(p, NULL);
     }
     return need_free;
 }
@@ -2691,12 +4915,12 @@ int async_ready(Port *p, void* data)
 static void
 report_missing_drv_callback(Port *p, char *drv_type, char *callback)
 {
-    ErtsPortNames *pnp = erts_get_port_names(p->id);
+    ErtsPortNames *pnp = erts_get_port_names(p->common.id);
     char *unknown = "<unknown>";
     char *drv_name = pnp->driver_name ? pnp->driver_name : unknown;
     char *prt_name = pnp->name ? pnp->name : unknown;
     erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();    
-    erts_dsprintf(dsbufp, "%T: %s driver '%s' ", p->id, drv_type, drv_name);
+    erts_dsprintf(dsbufp, "%T: %s driver '%s' ", p->common.id, drv_type, drv_name);
     if (sys_strcmp(drv_name, prt_name) != 0)
 	erts_dsprintf(dsbufp, "(%s) ", prt_name);
     erts_dsprintf(dsbufp, "does not implement the %s callback!\n", callback);
@@ -2711,7 +4935,7 @@ erts_stale_drv_select(Eterm port,
 		      int deselect)
 {
     char *type;
-    ErlDrvPort drv_port = internal_port_index(port);
+    ErlDrvPort drv_port = (ErlDrvPort) erts_port_lookup_raw(port);
     ErtsPortNames *pnp = erts_get_port_names(port);
     erts_dsprintf_buf_t *dsbufp;
 
@@ -2751,16 +4975,16 @@ erts_stale_drv_select(Eterm port,
 ErtsPortNames *
 erts_get_port_names(Eterm id)
 {
+    Port *prt = erts_port_lookup_raw(id);
     ErtsPortNames *pnp;
     ASSERT(is_nil(id) || is_internal_port(id));
-    
-    if (is_not_internal_port(id)) {
+
+    if (!prt) {
 	pnp = erts_alloc(ERTS_ALC_T_PORT_NAMES, sizeof(ErtsPortNames));
 	pnp->name = NULL;
 	pnp->driver_name = NULL;
     }
     else {
-	Port* prt = &erts_port[internal_port_index(id)];
 	int do_realloc = 1;
 	int len = -1;
 	size_t pnp_len = sizeof(ErtsPortNames);
@@ -2776,17 +5000,10 @@ erts_get_port_names(Eterm id)
 		pnp_len = sizeof(ErtsPortNames) + len;
 		pnp = erts_alloc(ERTS_ALC_T_PORT_NAMES, pnp_len);
 	    }
-	    erts_smp_port_state_lock(prt);
-	    if (id != prt->id) {
-		len = nlen = 0;
-		name = driver_name = NULL;
-	    }
-	    else {
-		name = prt->name;
-		len = nlen = name ? sys_strlen(name) + 1 : 0;
-		driver_name = (prt->drv_ptr ? prt->drv_ptr->name : NULL);
-		len += driver_name ? sys_strlen(driver_name) + 1 : 0;
-	    }
+	    name = prt->name;
+	    len = nlen = name ? sys_strlen(name) + 1 : 0;
+	    driver_name = (prt->drv_ptr ? prt->drv_ptr->name : NULL);
+	    len += driver_name ? sys_strlen(driver_name) + 1 : 0;
 	    if (len <= pnp_len - sizeof(ErtsPortNames)) {
 		if (!name)
 		    pnp->name = NULL;
@@ -2804,7 +5021,6 @@ erts_get_port_names(Eterm id)
 		}
 		do_realloc = 0;
 	    }
-	    erts_smp_port_state_unlock(prt);
 	} while (do_realloc);
     }
     return pnp;
@@ -2829,11 +5045,9 @@ static void schedule_port_timeout(Port *p)
      * /Rickard
      */
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p));
-    (void) erts_port_task_schedule(p->id,
-				   &p->timeout_task,
-				   ERTS_PORT_TASK_TIMEOUT,
-				   (ErlDrvEvent) -1,
-				   NULL);
+    erts_port_task_schedule(p->common.id,
+			    &p->timeout_task,
+			    ERTS_PORT_TASK_TIMEOUT);
 }
 
 ErlDrvTermData driver_mk_term_nil(void)
@@ -2841,9 +5055,9 @@ ErlDrvTermData driver_mk_term_nil(void)
     return driver_term_nil;
 }
 
-void driver_report_exit(int ix, int status)
+void driver_report_exit(ErlDrvPort ix, int status)
 {
-   Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
    Eterm* hp;
    Eterm tuple;
    Process *rp;
@@ -2856,7 +5070,7 @@ void driver_report_exit(int ix, int status)
    ERTS_SMP_CHK_NO_PROC_LOCKS;
    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-   pid = prt->connected;
+   pid = ERTS_PORT_GET_CONNECTED(prt);
    ASSERT(is_internal_pid(pid));
 
    rp = (scheduler
@@ -2869,7 +5083,7 @@ void driver_report_exit(int ix, int status)
 
    tuple = TUPLE2(hp, am_exit_status, make_small(status));
    hp += 3;
-   tuple = TUPLE2(hp, prt->id, tuple);
+   tuple = TUPLE2(hp, prt->common.id, tuple);
 
    erts_queue_message(rp, &rp_locks, bp, tuple, am_undefined
 #ifdef USE_VM_PROBES
@@ -2882,28 +5096,6 @@ void driver_report_exit(int ix, int status)
        erts_smp_proc_dec_refc(rp);
 }
 
-
-static ERTS_INLINE int
-deliver_term_check_port(ErlDrvPort drvport)
-{
-    int res;
-    int ix = (int) drvport;
-    if (ix < 0 || erts_max_ports <= ix)
-	res = -1; /* invalid */
-    else {
-	Port* prt = &erts_port[ix];
-	erts_smp_port_state_lock(prt);
-	if (!(prt->status & ERTS_PORT_SFLGS_INVALID_LOOKUP))
-	    res = 1; /* ok */
-	else if (prt->status & ERTS_PORT_SFLG_CLOSING)
-	    res = 0; /* closing */
-	else
-	    res = -1; /* invalid (dead) */
-	erts_smp_port_state_unlock(prt);
-    }
-    return res;
-}
-
 #define ERTS_B2T_STATES_DEF_STATES_SZ 5
 #define ERTS_B2T_STATES_DEF_STATES_INC 100
 
@@ -2991,10 +5183,7 @@ cleanup_b2t_states(struct b2t_states__ *b2tsp)
  */
 
 static int
-driver_deliver_term(ErlDrvPort port,
-		    Eterm to,
-		    ErlDrvTermData* data,
-		    int len)
+driver_deliver_term(Eterm to, ErlDrvTermData* data, int len)
 {
 #define ERTS_DDT_FAIL do { res = -1; goto done; } while (0)
     Uint need = 0;
@@ -3196,11 +5385,8 @@ driver_deliver_term(ErlDrvPort port,
     b2t.ix = 0;
 
     /*
-     * The term is OK. Go ahead and validate the port and process.
+     * The term is OK. Go ahead and validate the process.
      */
-    res = deliver_term_check_port(port);
-    if (res <= 0)
-	goto done;
 
     /*
      * Increase refc on proc if done from a non-scheduler thread.
@@ -3470,25 +5656,115 @@ driver_deliver_term(ErlDrvPort port,
 #undef ERTS_DDT_FAIL
 }
 
+static ERTS_INLINE int
+deliver_term_check_port(ErlDrvTermData port_id, Eterm *connected_p)
+{
+#ifdef ERTS_SMP
+    ErtsThrPrgrDelayHandle dhndl = erts_thr_progress_unmanaged_delay();
+#endif
+    Port *prt = erts_port_lookup_raw((Eterm) port_id);
+    erts_aint32_t state = erts_atomic32_read_nob(&prt->state);
+    if (connected_p) {
+#ifdef ERTS_SMP
+	if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED)
+	    ETHR_MEMBAR(ETHR_LoadLoad);
+#endif
+	*connected_p = ERTS_PORT_GET_CONNECTED(prt);
+    }
+#ifdef ERTS_SMP
+    if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED) {
+	erts_thr_progress_unmanaged_continue(dhndl);
+	ETHR_MEMBAR(ETHR_LoadLoad|ETHR_LoadStore);
+    }
+#endif
+    ERTS_SMP_LC_ASSERT(dhndl == ERTS_THR_PRGR_DHANDLE_MANAGED
+		       ? erts_lc_is_port_locked(prt)
+		       : !erts_lc_is_port_locked(prt));
+    return ((state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
+	    ? -1
+	    : ((state & ERTS_PORT_SFLG_CLOSING) ? 0 : 1));
+}
+
+int erl_drv_output_term(ErlDrvTermData port_id, ErlDrvTermData* data, int len)
+{
+    /* May be called from arbitrary thread */
+    Eterm connected;
+    int res = deliver_term_check_port(port_id, &connected);
+    if (res <= 0)
+	return res;
+    return driver_deliver_term(connected, data, len);
+}
 
+/*
+ * driver_output_term() is deprecated, and has been scheduled for
+ * removal in OTP-R17. It is replaced by erl_drv_output_term()
+ * above.
+ */
 int 
-driver_output_term(ErlDrvPort ix, ErlDrvTermData* data, int len)
+driver_output_term(ErlDrvPort drvport, ErlDrvTermData* data, int len)
 {
-    Port* prt = erts_drvport2port(ix);
+    erts_aint32_t state;
+    Port* prt;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
+    /* NOTE! It *not* safe to access 'drvport' from unmanaged threads. */
+    prt = erts_drvport2port(drvport, &state);
+    if (!prt)
+	return -1; /* invalid (dead) */
+    ERTS_SMP_CHK_NO_PROC_LOCKS;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-
-    if (prt == NULL)
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
 	return -1;
-    return driver_deliver_term(ix, prt->connected, data, len);
+    else if (state & ERTS_PORT_SFLG_CLOSING)
+	return 0;
+
+    return driver_deliver_term(ERTS_PORT_GET_CONNECTED(prt), data, len);
 }
 
+int erl_drv_send_term(ErlDrvTermData port_id,
+		      ErlDrvTermData to,
+		      ErlDrvTermData* data,
+		      int len)
+{
+    /* May be called from arbitrary thread */
+    int res = deliver_term_check_port(port_id, NULL);
+    if (res <= 0)
+	return res;
+    return driver_deliver_term(to, data, len);
+}
 
+/*
+ * driver_send_term() is deprecated, and has been scheduled for
+ * removal in OTP-R17. It is replaced by erl_drv_send_term() above.
+ */
 int
-driver_send_term(ErlDrvPort ix, ErlDrvTermData to, ErlDrvTermData* data, int len)
+driver_send_term(ErlDrvPort drvport,
+		 ErlDrvTermData to,
+		 ErlDrvTermData* data,
+		 int len)
 {
-    return driver_deliver_term(ix, to, data, len);
+    /*
+     * NOTE! It is *not* safe to access the 'drvport' parameter
+     * from unmanaged threads. Also note that it is impossible
+     * to make this access safe without using a less efficient
+     * internal data representation for ErlDrvPort.
+     */
+    ERTS_SMP_CHK_NO_PROC_LOCKS;
+#ifdef ERTS_SMP
+    if (erts_thr_progress_is_managed_thread())
+#endif
+    {
+	erts_aint32_t state;
+	Port* prt = erts_drvport2port(drvport, &state);
+	if (!prt)
+	    return -1; /* invalid (dead) */
+	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
+	if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
+	    return -1;
+	else if (state & ERTS_PORT_SFLG_CLOSING)
+	    return 0;
+    }
+    return driver_deliver_term(to, data, len);
 }
 
 
@@ -3500,26 +5776,27 @@ driver_send_term(ErlDrvPort ix, ErlDrvTermData to, ErlDrvTermData* data, int len
 int driver_output_binary(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
 			 ErlDrvBinary* bin, ErlDrvSizeT offs, ErlDrvSizeT len)
 {
-    Port* prt = erts_drvport2port(ix);
+    erts_aint32_t state;
+    Port* prt = erts_drvport2port(ix, &state);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
     if (prt == NULL)
 	return -1;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    if (prt->status & ERTS_PORT_SFLG_CLOSING)
+    if (state & ERTS_PORT_SFLG_CLOSING)
 	return 0;
 
     prt->bytes_in += (hlen + len);
     erts_smp_atomic_add_nob(&erts_bytes_in, (erts_aint_t) (hlen + len));
-    if (prt->status & ERTS_PORT_SFLG_DISTRIBUTION) {
+    if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
 	return erts_net_message(prt,
 				prt->dist_entry,
 				(byte*) hbuf, hlen,
 				(byte*) (bin->orig_bytes+offs), len);
     }
     else
-	deliver_bin_message(prt, prt->connected, 
+	deliver_bin_message(prt, ERTS_PORT_GET_CONNECTED(prt), 
 			    hbuf, hlen, bin, offs, len);
     return 0;
 }
@@ -3534,7 +5811,8 @@ int driver_output_binary(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
 int driver_output2(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
 		   char* buf, ErlDrvSizeT len)
 {
-    Port* prt = erts_drvport2port(ix);
+    erts_aint32_t state;
+    Port* prt = erts_drvport2port(ix, &state);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
@@ -3543,12 +5821,12 @@ int driver_output2(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    if (prt->status & ERTS_PORT_SFLG_CLOSING)
+    if (state & ERTS_PORT_SFLG_CLOSING)
 	return 0;
     
     prt->bytes_in += (hlen + len);
     erts_smp_atomic_add_nob(&erts_bytes_in, (erts_aint_t) (hlen + len));
-    if (prt->status & ERTS_PORT_SFLG_DISTRIBUTION) {
+    if (state & ERTS_PORT_SFLG_DISTRIBUTION) {
 	if (len == 0)
 	    return erts_net_message(prt,
 				    prt->dist_entry,
@@ -3560,10 +5838,12 @@ int driver_output2(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
 				    (byte*) hbuf, hlen,
 				    (byte*) buf, len);
     }
-    else if(prt->status & ERTS_PORT_SFLG_LINEBUF_IO)
-	deliver_linebuf_message(prt, prt->connected, hbuf, hlen, buf, len);
+    else if (state & ERTS_PORT_SFLG_LINEBUF_IO)
+	deliver_linebuf_message(prt, state, ERTS_PORT_GET_CONNECTED(prt),
+				hbuf, hlen, buf, len);
     else
-	deliver_read_message(prt, prt->connected, hbuf, hlen, buf, len, 0);
+	deliver_read_message(prt, state, ERTS_PORT_GET_CONNECTED(prt),
+			     hbuf, hlen, buf, len, 0);
     return 0;
 }
 
@@ -3584,6 +5864,7 @@ int driver_outputv(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
     SysIOVec* iov;
     ErlDrvBinary** binv;
     Port* prt;
+    erts_aint32_t state;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
@@ -3596,13 +5877,13 @@ int driver_outputv(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
     if (hlen < 0)
 	hlen = 0;
 
-    prt = erts_drvport2port(ix);
+    prt = erts_drvport2port(ix, &state);
     if (prt == NULL)
 	return -1;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    if (prt->status & ERTS_PORT_SFLG_CLOSING)
+    if (state & ERTS_PORT_SFLG_CLOSING)
 	return 0;
 
     /* size > 0 ! */
@@ -3627,7 +5908,8 @@ int driver_outputv(ErlDrvPort ix, char* hbuf, ErlDrvSizeT hlen,
     /* XXX handle distribution !!! */
     prt->bytes_in += (hlen + size);
     erts_smp_atomic_add_nob(&erts_bytes_in, (erts_aint_t) (hlen + size));
-    deliver_vec_message(prt, prt->connected, hbuf, hlen, binv, iov, n, size);
+    deliver_vec_message(prt, ERTS_PORT_GET_CONNECTED(prt), hbuf, hlen,
+			binv, iov, n, size);
     return 0;
 }
 
@@ -3738,8 +6020,7 @@ ErlDrvBinary* driver_realloc_binary(ErlDrvBinary* bin, ErlDrvSizeT size)
 }
 
 
-void driver_free_binary(dbin)
-ErlDrvBinary* dbin;
+void driver_free_binary(ErlDrvBinary* dbin)
 {
     Binary *bin;
     if (!dbin) {
@@ -3835,6 +6116,7 @@ static ERTS_INLINE void pdl_destroy(ErlDrvPDL pdl)
 {
     ERTS_LC_ASSERT(driver_pdl_get_refc(pdl) == 0);
     erts_mtx_destroy(&pdl->mtx);
+    erts_port_dec_refc(pdl->prt);
     erts_free(ERTS_ALC_T_PORT_DATA_LOCK, pdl);
 }
 
@@ -3872,16 +6154,18 @@ ErlDrvPDL
 driver_pdl_create(ErlDrvPort dp)
 {
     ErlDrvPDL pdl;
-    Port *pp = erts_drvport2port(dp);
+    Port *pp = erts_drvport2port(dp, NULL);
     if (!pp || pp->port_data_lock)
 	return NULL;
     pdl = erts_alloc(ERTS_ALC_T_PORT_DATA_LOCK,
 		     sizeof(struct erl_drv_port_data_lock));
     erts_mtx_init(&pdl->mtx, "port_data_lock");
     pdl_init_refc(pdl);
+    erts_port_inc_refc(pp);
+    pdl->prt = pp;
     pp->port_data_lock = pdl;
 #ifdef HARDDEBUG
-    erts_fprintf(stderr, "driver_pdl_create(%T) -> 0x%08X\r\n",pp->id,(unsigned) pdl);
+    erts_fprintf(stderr, "driver_pdl_create(%T) -> 0x%08X\r\n",pp->common.id,(unsigned) pdl);
 #endif
     return pdl;
 }
@@ -4319,33 +6603,33 @@ static ERTS_INLINE void
 drv_cancel_timer(Port *prt)
 {
 #ifdef ERTS_SMP
-    erts_cancel_smp_ptimer(prt->ptimer);
+    erts_cancel_smp_ptimer(prt->common.u.alive.ptimer);
 #else
-    erts_cancel_timer(&prt->tm);
+    erts_cancel_timer(&prt->common.u.alive.tm);
 #endif
     if (erts_port_task_is_scheduled(&prt->timeout_task))
-	erts_port_task_abort(prt->id, &prt->timeout_task);
+	erts_port_task_abort(&prt->timeout_task);
 }
 
 int driver_set_timer(ErlDrvPort ix, unsigned long t)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
     if (prt == NULL)
 	return -1;
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
+
     if (prt->drv_ptr->timeout == NULL)
 	return -1;
     drv_cancel_timer(prt);
 #ifdef ERTS_SMP
-    erts_create_smp_ptimer(&prt->ptimer,
-			   prt->id,
+    erts_create_smp_ptimer(&prt->common.u.alive.ptimer,
+			   prt->common.id,
 			   (ErlTimeoutProc) schedule_port_timeout,
 			   t);
 #else
-    erts_set_timer(&prt->tm,
+    erts_set_timer(&prt->common.u.alive.tm,
 		  (ErlTimeoutProc) schedule_port_timeout,
 		  NULL,
 		  prt,
@@ -4356,7 +6640,7 @@ int driver_set_timer(ErlDrvPort ix, unsigned long t)
 
 int driver_cancel_timer(ErlDrvPort ix)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     if (prt == NULL)
 	return -1;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
@@ -4368,7 +6652,7 @@ int driver_cancel_timer(ErlDrvPort ix)
 int
 driver_read_timer(ErlDrvPort ix, unsigned long* t)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
@@ -4376,9 +6660,11 @@ driver_read_timer(ErlDrvPort ix, unsigned long* t)
 	return -1;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 #ifdef ERTS_SMP
-    *t = prt->ptimer ? erts_time_left(&prt->ptimer->timer.tm) : 0;
+    *t = (prt->common.u.alive.ptimer
+	  ? erts_time_left(&prt->common.u.alive.ptimer->timer.tm)
+	  : 0);
 #else
-    *t = erts_time_left(&prt->tm);
+    *t = erts_time_left(&prt->common.u.alive.tm);
 #endif
     return 0;
 }
@@ -4429,8 +6715,8 @@ static int do_driver_monitor_process(Port *prt,
     }
 
     ref = erts_make_ref_in_buffer(buf);
-    erts_add_monitor(&(prt->monitors), MON_ORIGIN, ref, rp->id, NIL);
-    erts_add_monitor(&(rp->monitors), MON_TARGET, ref, prt->id, NIL);
+    erts_add_monitor(&ERTS_P_MONITORS(prt), MON_ORIGIN, ref, rp->common.id, NIL);
+    erts_add_monitor(&ERTS_P_MONITORS(rp), MON_TARGET, ref, prt->common.id, NIL);
 
     erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
     ref_to_driver_monitor(ref,monitor);
@@ -4440,31 +6726,24 @@ static int do_driver_monitor_process(Port *prt,
 /*
  * This can be called from a non scheduler thread iff a port_data_lock exists
  */
-int driver_monitor_process(ErlDrvPort port,
+int driver_monitor_process(ErlDrvPort drvport,
 			   ErlDrvTermData process,
 			   ErlDrvMonitor *monitor)
 {
     Port *prt;
     int ret;
-    Uint32 status;
+    erts_aint32_t state;
+#if !HEAP_ON_C_STACK || (defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK))
     ErtsSchedulerData *sched = erts_get_scheduler_data();
-    int ix = (int) port;
-    if (ix < 0 || erts_max_ports <= ix) {
-	return -1;
-    }
-    prt = &erts_port[ix];
+#endif
+
+    prt = erts_thr_drvport2port_raw(drvport);
 
     DRV_MONITOR_LOCK_PDL(prt);
 
-    if (sched) {
-	status = erts_port[ix].status;
-    } else {
-	erts_smp_port_state_lock(prt);
-	status = erts_port[ix].status;
-	erts_smp_port_state_unlock(prt);
-    }
+    state = erts_atomic32_read_nob(&prt->state);
 
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return -1;
     }
@@ -4502,7 +6781,7 @@ static int do_driver_demonitor_process(Port *prt, Eterm *buf,
 
     memcpy(buf,monitor,sizeof(Eterm)*REF_THING_SIZE);
     ref = make_internal_ref(buf);
-    mon = erts_lookup_monitor(prt->monitors, ref);
+    mon = erts_lookup_monitor(ERTS_P_MONITORS(prt), ref);
     if (mon == NULL) {
 	return 1;
     }
@@ -4514,13 +6793,13 @@ static int do_driver_demonitor_process(Port *prt, Eterm *buf,
 			   to,
 			   ERTS_PROC_LOCK_LINK,
 			   ERTS_P2P_FLG_ALLOW_OTHER_X);
-    mon = erts_remove_monitor(&(prt->monitors), ref);
+    mon = erts_remove_monitor(&ERTS_P_MONITORS(prt), ref);
     if (mon) {
 	erts_destroy_monitor(mon);
     }
     if (rp) {
 	ErtsMonitor *rmon;
-	rmon = erts_remove_monitor(&(rp->monitors), ref);
+	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
 	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
 	if (rmon != NULL) {
 	    erts_destroy_monitor(rmon);
@@ -4529,30 +6808,23 @@ static int do_driver_demonitor_process(Port *prt, Eterm *buf,
     return 0;
 }
 
-int driver_demonitor_process(ErlDrvPort port,
+int driver_demonitor_process(ErlDrvPort drvport,
 			     const ErlDrvMonitor *monitor)
 {
     Port *prt;
     int ret;
-    Uint32 status;
+    erts_aint32_t state;
+#if !HEAP_ON_C_STACK || (defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK))
     ErtsSchedulerData *sched = erts_get_scheduler_data();
-    int ix = (int) port;
-    if (ix < 0 || erts_max_ports <= ix) {
-	return -1;
-    }
-    prt = &erts_port[ix];
+#endif
+
+    prt = erts_thr_drvport2port_raw(drvport);
 
     DRV_MONITOR_LOCK_PDL(prt);
 
-    if (sched) {
-	status = erts_port[ix].status;
-    } else {
-	erts_smp_port_state_lock(prt);
-	status = erts_port[ix].status;
-	erts_smp_port_state_unlock(prt);
-    }
+    state = erts_atomic32_read_nob(&prt->state);
 
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return -1;
     }
@@ -4588,7 +6860,7 @@ static ErlDrvTermData do_driver_get_monitored_process(Port *prt, Eterm *buf,
 
     memcpy(buf,monitor,sizeof(Eterm)*REF_THING_SIZE);
     ref = make_internal_ref(buf);
-    mon = erts_lookup_monitor(prt->monitors, ref);
+    mon = erts_lookup_monitor(ERTS_P_MONITORS(prt), ref);
     if (mon == NULL) {
 	return driver_term_nil;
     }
@@ -4599,30 +6871,22 @@ static ErlDrvTermData do_driver_get_monitored_process(Port *prt, Eterm *buf,
 }
 
 
-ErlDrvTermData driver_get_monitored_process(ErlDrvPort port,
+ErlDrvTermData driver_get_monitored_process(ErlDrvPort drvport,
 					    const ErlDrvMonitor *monitor)
 {
     Port *prt;
     ErlDrvTermData ret;
-    Uint32 status;
+    erts_aint32_t state;
+#if !HEAP_ON_C_STACK || (defined(ERTS_SMP) && defined(ERTS_ENABLE_LOCK_CHECK))
     ErtsSchedulerData *sched = erts_get_scheduler_data();
-    int ix = (int) port;
-    if (ix < 0 || erts_max_ports <= ix) {
-	return driver_term_nil;
-    }
-    prt = &erts_port[ix];
+#endif
 
-    DRV_MONITOR_LOCK_PDL(prt);
+    prt = erts_thr_drvport2port_raw(drvport);
 
-    if (sched) {
-	status = erts_port[ix].status;
-    } else {
-	erts_smp_port_state_lock(prt);
-	status = erts_port[ix].status;
-	erts_smp_port_state_unlock(prt);
-    }
+    DRV_MONITOR_LOCK_PDL(prt);
 
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    state = erts_atomic32_read_nob(&prt->state);
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return driver_term_nil;
     }
@@ -4667,7 +6931,7 @@ void erts_fire_port_monitor(Port *prt, Eterm ref)
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
     ASSERT(prt->drv_ptr != NULL);    
     DRV_MONITOR_LOCK_PDL(prt);
-    if (erts_lookup_monitor(prt->monitors,ref) == NULL) {
+    if (erts_lookup_monitor(ERTS_P_MONITORS(prt), ref) == NULL) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return;
     }
@@ -4677,7 +6941,7 @@ void erts_fire_port_monitor(Port *prt, Eterm ref)
     DRV_MONITOR_UNLOCK_PDL(prt);
 #ifdef USE_VM_PROBES
     if (DTRACE_ENABLED(driver_process_exit)) {
-        DTRACE_FORMAT_COMMON_PID_AND_PORT(prt->connected, prt)
+        DTRACE_FORMAT_COMMON_PID_AND_PORT(ERTS_PORT_GET_CONNECTED(prt), prt)
         DTRACE3(driver_process_exit, process_str, port_str, prt->name);
     }
 #endif
@@ -4686,7 +6950,7 @@ void erts_fire_port_monitor(Port *prt, Eterm ref)
     erts_unblock_fpe(fpe_was_unmasked);
     DRV_MONITOR_LOCK_PDL(prt);
     /* remove monitor *after* callback */
-    rmon = erts_remove_monitor(&(prt->monitors),ref);
+    rmon = erts_remove_monitor(&ERTS_P_MONITORS(prt), ref);
     DRV_MONITOR_UNLOCK_PDL(prt);
     if (rmon) {
 	erts_destroy_monitor(rmon);
@@ -4697,7 +6961,8 @@ void erts_fire_port_monitor(Port *prt, Eterm ref)
 static int
 driver_failure_term(ErlDrvPort ix, Eterm term, int eof)
 {
-    Port* prt = erts_drvport2port(ix);
+    erts_aint32_t state;
+    Port* prt = erts_drvport2port(ix, &state);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
@@ -4705,19 +6970,19 @@ driver_failure_term(ErlDrvPort ix, Eterm term, int eof)
 	return -1;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
     if (eof)
-	flush_linebuf_messages(prt);
-    if (prt->status & ERTS_PORT_SFLG_CLOSING) {
+	flush_linebuf_messages(prt, state);
+    if (state & ERTS_PORT_SFLG_CLOSING) {
 	terminate_port(prt);
-    } else if (eof && (prt->status & ERTS_PORT_SFLG_SOFT_EOF)) {
-	deliver_result(prt->id, prt->connected, am_eof);
+    } else if (eof && (state & ERTS_PORT_SFLG_SOFT_EOF)) {
+	deliver_result(prt->common.id, ERTS_PORT_GET_CONNECTED(prt), am_eof);
     } else {
-	/* XXX UGLY WORK AROUND, Let do_exit_port terminate the port */
+	/* XXX UGLY WORK AROUND, Let erts_deliver_port_exit() terminate the port */
 	if (prt->port_data_lock)
 	    driver_pdl_lock(prt->port_data_lock);
 	prt->ioq.size = 0;
 	if (prt->port_data_lock)
 	    driver_pdl_unlock(prt->port_data_lock);
-	erts_do_exit_port(prt, prt->id, eof ? am_normal : term);
+	erts_deliver_port_exit(prt, prt->common.id, eof ? am_normal : term, 0);
     }
     return 0;
 }
@@ -4730,23 +6995,23 @@ driver_failure_term(ErlDrvPort ix, Eterm term, int eof)
 */
 int driver_exit(ErlDrvPort ix, int err)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     Process* rp;
     ErtsLink *lnk, *rlnk = NULL;
+    Eterm connected;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
   
     if (prt == NULL)
         return -1;
 
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-
-    rp = erts_pid2proc(NULL, 0, prt->connected, ERTS_PROC_LOCK_LINK);
+    connected = ERTS_PORT_GET_CONNECTED(prt);
+    rp = erts_pid2proc(NULL, 0, connected, ERTS_PROC_LOCK_LINK);
     if (rp) {
-	rlnk = erts_remove_link(&(rp->nlinks),prt->id);
+	rlnk = erts_remove_link(&ERTS_P_LINKS(rp),prt->common.id);
     }
 
-    lnk = erts_remove_link(&(prt->nlinks),prt->connected);
+    lnk = erts_remove_link(&ERTS_P_LINKS(prt), connected);
 
 #ifdef ERTS_SMP
     if (rp)
@@ -4803,24 +7068,24 @@ ErlDrvTermData driver_mk_atom(char* string)
 
 ErlDrvTermData driver_mk_port(ErlDrvPort ix)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    return (ErlDrvTermData) prt->id;
+    return (ErlDrvTermData) prt->common.id;
 }
 
 ErlDrvTermData driver_connected(ErlDrvPort ix)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     if (prt == NULL)
 	return NIL;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    return prt->connected;
+    return ERTS_PORT_GET_CONNECTED(prt);
 }
 
 ErlDrvTermData driver_caller(ErlDrvPort ix)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     if (prt == NULL)
 	return NIL;
@@ -4830,25 +7095,25 @@ ErlDrvTermData driver_caller(ErlDrvPort ix)
 
 int driver_lock_driver(ErlDrvPort ix)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
     DE_Handle* dh;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    erts_smp_mtx_lock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rwlock(&erts_driver_list_lock);
 
     if (prt == NULL) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
 	return -1;
     }
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
     if ((dh = (DE_Handle*)prt->drv_ptr->handle ) == NULL) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
 	return -1;
     }
     erts_ddll_lock_driver(dh, prt->drv_ptr->name);
-    erts_smp_mtx_unlock(&erts_driver_list_lock);
+    erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
     return 0;
 }
 
@@ -4858,7 +7123,7 @@ static int maybe_lock_driver_list(void)
     void *rec_lock;
     rec_lock = erts_smp_tsd_get(driver_list_lock_status_key);
     if (rec_lock == 0) {
-	erts_smp_mtx_lock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwlock(&erts_driver_list_lock);
 	return 1;
     }
     return 0;
@@ -4866,7 +7131,7 @@ static int maybe_lock_driver_list(void)
 static void maybe_unlock_driver_list(int doit)
 {
     if (doit) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
     }
 }
 /* 
@@ -5035,7 +7300,7 @@ no_event_callback(ErlDrvData drv_data, ErlDrvEvent event, ErlDrvEventData event_
 {
     Port *prt = get_current_port();
     report_missing_drv_callback(prt, "Event", "event()");
-    driver_event((ErlDrvPort) internal_port_index(prt->id), event, NULL);
+    driver_event((ErlDrvPort) prt, event, NULL);
 }
 
 static void
@@ -5043,7 +7308,7 @@ no_ready_input_callback(ErlDrvData drv_data, ErlDrvEvent event)
 {
     Port *prt = get_current_port();
     report_missing_drv_callback(prt, "Input", "ready_input()");
-    driver_select((ErlDrvPort) internal_port_index(prt->id), event, 
+    driver_select((ErlDrvPort) prt, event, 
 		  (ERL_DRV_READ | ERL_DRV_USE_NO_CALLBACK), 0);
 }
 
@@ -5052,7 +7317,7 @@ no_ready_output_callback(ErlDrvData drv_data, ErlDrvEvent event)
 {
     Port *prt = get_current_port();
     report_missing_drv_callback(prt, "Output", "ready_output()");
-    driver_select((ErlDrvPort) internal_port_index(prt->id), event,
+    driver_select((ErlDrvPort) prt, event,
 		  (ERL_DRV_WRITE | ERL_DRV_USE_NO_CALLBACK), 0);
 }
 
@@ -5087,13 +7352,13 @@ init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
 	drv->lock = NULL;
     else {
 	drv->lock = erts_alloc(ERTS_ALC_T_DRIVER_LOCK,
-			       sizeof(erts_smp_mtx_t));
-	erts_smp_mtx_init_x(drv->lock,
-			    "driver_lock",
+			       sizeof(erts_mtx_t));
+	erts_mtx_init_x(drv->lock,
+			"driver_lock",
 #if defined(ERTS_ENABLE_LOCK_CHECK) || defined(ERTS_ENABLE_LOCK_COUNT)
-			    am_atom_put(drv->name, sys_strlen(drv->name))
+			am_atom_put(drv->name, sys_strlen(drv->name))
 #else
-			    NIL
+			NIL
 #endif
 	    );
     }
@@ -5165,7 +7430,7 @@ int erts_add_driver_entry(ErlDrvEntry *de, DE_Handle *handle, int driver_list_lo
     int res;
 
     if (!driver_list_locked) {
-	erts_smp_mtx_lock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwlock(&erts_driver_list_lock);
     }
 
     dp->next = driver_list;
@@ -5194,7 +7459,7 @@ int erts_add_driver_entry(ErlDrvEntry *de, DE_Handle *handle, int driver_list_lo
 	
     if (!driver_list_locked) {
 	erts_smp_tsd_set(driver_list_lock_status_key, NULL);
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
     }
     return res;
 }
@@ -5207,7 +7472,7 @@ int remove_driver_entry(ErlDrvEntry *drv)
     
     rec_lock = erts_smp_tsd_get(driver_list_lock_status_key);
     if (rec_lock == NULL) {
-	erts_smp_mtx_lock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwlock(&erts_driver_list_lock);
     }
     dp = driver_list;
     while (dp && dp->entry != drv)
@@ -5215,7 +7480,7 @@ int remove_driver_entry(ErlDrvEntry *drv)
     if (dp) {
 	if (dp->handle) {
 	    if (rec_lock == NULL) {
-		erts_smp_mtx_unlock(&erts_driver_list_lock);
+		erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
 	    }
 	    return -1;
 	}
@@ -5229,12 +7494,12 @@ int remove_driver_entry(ErlDrvEntry *drv)
 	}
 	erts_destroy_driver(dp);
 	if (rec_lock == NULL) {
-	    erts_smp_mtx_unlock(&erts_driver_list_lock);
+	    erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
 	}
 	return 1;
     }
     if (rec_lock == NULL) {
-	erts_smp_mtx_unlock(&erts_driver_list_lock);
+	erts_smp_rwmtx_rwunlock(&erts_driver_list_lock);
     }
     return 0;
 }
@@ -5264,18 +7529,22 @@ erl_drv_getenv(char *key, char *value, size_t *value_size)
  * - uses the fact that heart_port is registered when starting heart
  */
 
-Port *erts_get_heart_port() {
+Port *erts_get_heart_port(void)
+{
+    int ix, max = erts_ptab_max(&erts_port);
 
-    Port* port;
-    Uint  ix;
+    for (ix = 0; ix < max; ix++) {
+	struct reg_proc *reg;
+	Port *port = erts_pix2port(ix);
 
-    for(ix = 0; ix < erts_max_ports; ix++) {
-	port = &erts_port[ix];
+	if (!port)
+	    continue;
 	/* only examine undead or alive ports */
-	if (port->status & ERTS_PORT_SFLGS_DEAD)
+	if (erts_atomic32_read_nob(&port->state) & ERTS_PORT_SFLGS_DEAD)
 	    continue;
 	/* immediate atom compare */
-	if (port->reg && port->reg->name == am_heart_port) {
+	reg = port->common.u.alive.reg;
+	if (reg && reg->name == am_heart_port) {
 	    return port;
 	}
     }