Atomic port state

16 files changed, 709 insertions, 442 deletions

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 89a8f839db..10dcba565b 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -1899,30 +1899,34 @@ do_send(Process *p, Eterm to, Eterm msg, int suspend) {
 	ERTS_SMP_LC_ASSERT(!pt || erts_lc_is_port_locked(pt));
         
 	/* We have waited for locks, trace schedule ports */
-	if (pt && IS_TRACED_FL(pt, F_TRACE_SCHED_PORTS)) {
-	    trace_sched_ports_where(pt, am_in, am_command);
-	}
-	if (pt && erts_system_profile_flags.runnable_ports && !erts_port_is_scheduled(pt)) {
-	    profile_runnable_port(pt, am_active);
-	}
-	
-	/* XXX let port_command handle the busy stuff !!! */
-	if (pt && (pt->status & ERTS_PORT_SFLG_PORT_BUSY)) {
-	    if (suspend) {
-		erts_suspend(p, ERTS_PROC_LOCK_MAIN, pt);
-		if (erts_system_monitor_flags.busy_port) {
-		    monitor_generic(p, am_busy_port, portid);
-		}
-	    }
-	    /* Virtually schedule out the port before releasing */
+	if (pt) {
+	    erts_aint32_t state;
 	    if (IS_TRACED_FL(pt, F_TRACE_SCHED_PORTS)) {
-	    	trace_sched_ports_where(pt, am_out, am_command);
+		trace_sched_ports_where(pt, am_in, am_command);
 	    }
 	    if (erts_system_profile_flags.runnable_ports && !erts_port_is_scheduled(pt)) {
-	    	profile_runnable_port(pt, am_inactive);
+		profile_runnable_port(pt, am_active);
+	    }
+	
+	    state = erts_smp_atomic32_read_nob(&pt->state);
+	    /* XXX let port_command handle the busy stuff !!! */
+	    if (state & ERTS_PORT_SFLG_PORT_BUSY) {
+		if (suspend) {
+		    erts_suspend(p, ERTS_PROC_LOCK_MAIN, pt);
+		    if (erts_system_monitor_flags.busy_port) {
+			monitor_generic(p, am_busy_port, portid);
+		    }
+		}
+		/* Virtually schedule out the port before releasing */
+		if (IS_TRACED_FL(pt, F_TRACE_SCHED_PORTS)) {
+		    trace_sched_ports_where(pt, am_out, am_command);
+		}
+		if (erts_system_profile_flags.runnable_ports && !erts_port_is_scheduled(pt)) {
+		    profile_runnable_port(pt, am_inactive);
+		}
+		erts_port_release(pt);
+		return SEND_YIELD;
 	    }
-	    erts_port_release(pt);
-	    return SEND_YIELD;
 	}
 	
 	if (IS_TRACED(p)) 	/* trace once only !! */
@@ -3534,14 +3538,17 @@ BIF_RETTYPE ports_0(BIF_ALIST_0)
 
     for (i = erts_max_ports-1; i >= 0; i--) {
 	Port* prt = &erts_port[i];
-	erts_smp_port_state_lock(prt);
-	if (!(prt->status & ERTS_PORT_SFLGS_DEAD)
-	    && prt->snapshot != next_ss) {
-	    ASSERT(prt->snapshot == next_ss - 1);
-	    *pp++ = prt->id;		
-	    prt->snapshot = next_ss; /* Consumed by this snapshot */
+	erts_aint32_t state = erts_smp_atomic32_read_acqb(&prt->state);
+	if (!(state & ERTS_PORT_SFLGS_DEAD)) {
+	    erts_smp_port_minor_lock(prt);
+	    state = erts_smp_atomic32_read_nob(&prt->state);
+	    if (!(state & ERTS_PORT_SFLGS_DEAD) && prt->snapshot != next_ss) {
+		ASSERT(prt->snapshot == next_ss - 1);
+		*pp++ = prt->id;
+		prt->snapshot = next_ss; /* Consumed by this snapshot */
+	    }
+	    erts_smp_port_minor_unlock(prt);
 	}
-	erts_smp_port_state_unlock(prt);
     }
 
     dead_ports = (Eterm*)erts_smp_atomic_xchg_nob(&erts_dead_ports_ptr,
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index 5de8236a7e..eccef44a11 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -423,7 +423,8 @@ int erts_do_net_exits(DistEntry *dep, Eterm reason)
 
 	    prt = erts_id2port(prt_id, NULL, 0);
 	    if (prt) {
-		ASSERT(prt->status & ERTS_PORT_SFLG_DISTRIBUTION);
+		ASSERT(erts_smp_atomic32_read_nob(&prt->state)
+		       & ERTS_PORT_SFLG_DISTRIBUTION);
 		ASSERT(prt->dist_entry);
 		/* will call do_net_exists !!! */
 		erts_do_exit_port(prt, prt_id, nd_reason);
@@ -1907,13 +1908,13 @@ int
 erts_dist_command(Port *prt, int reds_limit)
 {
     Sint reds = ERTS_PORT_REDS_DIST_CMD_START;
-    int prt_busy;
     Uint32 status;
     Uint32 flags;
     Sint obufsize = 0;
     ErtsDistOutputQueue oq, foq;
     DistEntry *dep = prt->dist_entry;
     Uint (*send)(Port *prt, ErtsDistOutputBuf *obuf);
+    erts_aint32_t state;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
@@ -1956,12 +1957,12 @@ erts_dist_command(Port *prt, int reds_limit)
     dep->finalized_out_queue.first = NULL;
     dep->finalized_out_queue.last = NULL;
 
+    state = erts_smp_atomic32_read_nob(&prt->state);
+
     if (reds > reds_limit)
 	goto preempted;
 
-    prt_busy = (int) (prt->status & ERTS_PORT_SFLG_PORT_BUSY);
-
-    if (!prt_busy && foq.first) {
+    if (!(state & ERTS_PORT_SFLG_PORT_BUSY) && foq.first) {
 	int preempt = 0;
 	do {
 	    Uint size;
@@ -1977,11 +1978,10 @@ erts_dist_command(Port *prt, int reds_limit)
 	    obufsize += size_obuf(fob);
 	    foq.first = foq.first->next;
 	    free_dist_obuf(fob);
-	    preempt = reds > reds_limit || (prt->status & ERTS_PORT_SFLGS_DEAD);
-	    if (prt->status & ERTS_PORT_SFLG_PORT_BUSY) {
-		prt_busy = 1;
+	    state = erts_smp_atomic32_read_nob(&prt->state);
+	    preempt = reds > reds_limit || (state & ERTS_PORT_SFLGS_DEAD);
+	    if (state & ERTS_PORT_SFLG_PORT_BUSY)
 		break;
-	    }
 	} while (foq.first && !preempt);
 	if (!foq.first)
 	    foq.last = NULL;
@@ -1989,7 +1989,7 @@ erts_dist_command(Port *prt, int reds_limit)
 	    goto preempted;
     }
 
-    if (prt_busy) {
+    if (state & ERTS_PORT_SFLG_PORT_BUSY) {
 	if (oq.first) {
 	    ErtsDistOutputBuf *ob;
 	    int preempt;
@@ -2060,12 +2060,10 @@ erts_dist_command(Port *prt, int reds_limit)
 	    obufsize += size_obuf(fob);
 	    oq.first = oq.first->next;
 	    free_dist_obuf(fob);
-	    preempt = reds > reds_limit || (prt->status & ERTS_PORT_SFLGS_DEAD);
-	    if (prt->status & ERTS_PORT_SFLG_PORT_BUSY) {
-		prt_busy = 1;
-		if (oq.first && !preempt)
-		    goto finalize_only;
-	    }
+	    state = erts_smp_atomic32_read_nob(&prt->state);
+	    preempt = reds > reds_limit || (state & ERTS_PORT_SFLGS_DEAD);
+	    if ((state & ERTS_PORT_SFLG_PORT_BUSY) && oq.first && !preempt)
+		goto finalize_only;
 	}
 
 	ASSERT(!oq.first || preempt);
@@ -2093,7 +2091,7 @@ erts_dist_command(Port *prt, int reds_limit)
 	ASSERT(dep->qsize >= obufsize);
 	dep->qsize -= obufsize;
 	obufsize = 0;
-	if (!prt_busy
+	if (!(state & ERTS_PORT_SFLG_PORT_BUSY)
 	    && (dep->qflgs & ERTS_DE_QFLG_BUSY)
 	    && dep->qsize < erts_dist_buf_busy_limit) {
 	    ErtsProcList *suspendees;
@@ -2139,11 +2137,15 @@ erts_dist_command(Port *prt, int reds_limit)
     return reds;
 
  preempted:
+    /*
+     * Here we assume that state has been read
+     * since last call to driver.
+     */
 
     ASSERT(oq.first || !oq.last);
     ASSERT(!oq.first || oq.last);
 
-    if (prt->status & ERTS_PORT_SFLGS_DEAD) {
+    if (state & ERTS_PORT_SFLGS_DEAD) {
 	/*
 	 * Port died during port command; clean up 'oq'
 	 * and 'foq'. Things buffered in dist entry after
@@ -2581,7 +2583,8 @@ BIF_RETTYPE setnode_3(BIF_ALIST_3)
     pp = erts_id2port(BIF_ARG_2, BIF_P, ERTS_PROC_LOCK_MAIN);
     erts_smp_de_rwlock(dep);
 
-    if (!pp || (pp->status & ERTS_PORT_SFLG_EXITING))
+    if (!pp || (erts_smp_atomic32_read_nob(&pp->state)
+		& ERTS_PORT_SFLG_EXITING))
 	goto badarg;
 
     if ((pp->drv_ptr->flags & ERL_DRV_FLAG_SOFT_BUSY) == 0)
@@ -2610,7 +2613,7 @@ BIF_RETTYPE setnode_3(BIF_ALIST_3)
     if (pp->dist_entry || is_not_nil(dep->cid))
 	goto badarg;
 
-    erts_port_status_bor_set(pp, ERTS_PORT_SFLG_DISTRIBUTION);
+    erts_smp_atomic32_read_bor_nob(&pp->state, ERTS_PORT_SFLG_DISTRIBUTION);
 
     pp->dist_entry = dep;
 
diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index 845151c895..0cefd73459 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -187,7 +187,8 @@ void erts_schedule_dist_command(Port *prt, DistEntry *dist_entry)
 
     if (prt) {
 	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-	ASSERT((erts_port_status_get(prt) & ERTS_PORT_SFLGS_DEAD) == 0);
+	ASSERT((erts_smp_atomic32_read_nob(&prt->state)
+		& ERTS_PORT_SFLGS_DEAD) == 0);
 	ASSERT(prt->dist_entry);
 
 	dep = prt->dist_entry;
diff --git a/erts/emulator/beam/erl_async.c b/erts/emulator/beam/erl_async.c
index f321ed21aa..bce9d07a01 100644
--- a/erts/emulator/beam/erl_async.c
+++ b/erts/emulator/beam/erl_async.c
@@ -599,7 +599,7 @@ long driver_async(ErlDrvPort ix, unsigned int* key,
 	sched_id = 1;
 #endif
 
-    prt = erts_drvport2port(ix);
+    prt = erts_drvport2port(ix, NULL);
     if (!prt)
 	return -1;
 
diff --git a/erts/emulator/beam/erl_bif_ddll.c b/erts/emulator/beam/erl_bif_ddll.c
index 7f7c975e78..dfb8b453c4 100644
--- a/erts/emulator/beam/erl_bif_ddll.c
+++ b/erts/emulator/beam/erl_bif_ddll.c
@@ -114,6 +114,54 @@ static void ddll_no_more_references(void *vdh);
 
 #define FREE_PORT_FLAGS (ERTS_PORT_SFLGS_DEAD & (~ERTS_PORT_SFLG_INITIALIZING))
 
+static void
+kill_ports_driver_unloaded(DE_Handle *dh)
+{
+    int ix;
+
+    for (ix = 0; ix < erts_max_ports; ix++) {
+	Port* prt = &erts_port[ix];
+	erts_aint32_t state;
+	state = erts_smp_atomic32_read_acqb(&prt->state);
+	if (state & FREE_PORT_FLAGS)
+	    continue;
+
+	erts_smp_port_minor_lock(prt);
+
+	if (prt->drv_ptr->handle != dh) {
+	    erts_smp_port_minor_unlock(prt);
+	    continue;
+	}
+
+	erts_smp_atomic_inc_nob(&prt->refc);
+	erts_smp_port_minor_unlock(prt);
+
+	state = erts_smp_atomic32_read_acqb(&prt->state);
+	if (!(state & FREE_PORT_FLAGS)) {
+#if DDLL_SMP
+	    if (state & ERTS_PORT_SFLG_INITIALIZING) {
+		/* Extremely rare busy wait */
+		do {
+		    ERTS_SPIN_BODY;
+		    state = erts_smp_atomic32_read_acqb(&prt->state);
+		} while (state & ERTS_PORT_SFLG_INITIALIZING);
+	    }
+
+	    erts_smp_mtx_lock(prt->lock);
+
+	    if (prt->drv_ptr->handle == dh) {
+		state = erts_smp_atomic32_read_acqb(&prt->state);
+		if (!(state & ERTS_PORT_SFLGS_DEAD))
+		    driver_failure_atom(ix, "driver_unloaded");
+	    }
+#else
+	    driver_failure_atom(ix, "driver_unloaded");
+#endif
+	    erts_port_release(prt);
+	}
+    }
+}
+
 /*
  *    try_load(Path, Name, OptionList) -> {ok,Status} | 
  *                                        {ok, PendingStatus, Ref} | 
@@ -358,38 +406,14 @@ BIF_RETTYPE erl_ddll_try_load_3(BIF_ALIST_3)
     }
     assert_drv_list_locked();
     if (kill_ports) {
-	int j;
-	/* Avoid closing the driver by referencing it */
+ 	/* Avoid closing the driver by referencing it */
 	erts_ddll_reference_driver(dh);
 	ASSERT(dh->status == ERL_DE_RELOAD);
 	dh->status = ERL_DE_FORCE_RELOAD;
 #if DDLL_SMP
 	unlock_drv_list();
 #endif
-	for (j = 0; j < erts_max_ports; j++) {
-	    Port* prt = &erts_port[j];
-	    erts_smp_port_state_lock(prt);
-	    if (!(prt->status & FREE_PORT_FLAGS) &&
-		prt->drv_ptr->handle == dh) {
-		erts_smp_atomic_inc_nob(&prt->refc);
-#if DDLL_SMP
-		/* Extremely rare spinlock */
-		while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
-		       erts_smp_port_state_unlock(prt);
-		       erts_smp_port_state_lock(prt);
-	        }
-		erts_smp_port_state_unlock(prt);
-		erts_smp_mtx_lock(prt->lock);
-		if (!(prt->status & ERTS_PORT_SFLGS_DEAD)) {
-		    driver_failure_atom(j, "driver_unloaded");
-		}
-#else
-		driver_failure_atom(j, "driver_unloaded");
-#endif
-		erts_port_release(prt);
-	    }
-	    else erts_smp_port_state_unlock(prt);
-	}
+	kill_ports_driver_unloaded(dh);
 	/* Dereference, eventually causing driver destruction */
 #if DDLL_SMP
 	lock_drv_list(); 
@@ -587,37 +611,13 @@ Eterm erl_ddll_try_unload_2(BIF_ALIST_2)
 done:
     assert_drv_list_locked();
     if (kill_ports > 1) {
-	int j;
 	/* Avoid closing the driver by referencing it */
 	erts_ddll_reference_driver(dh);
 	dh->status = ERL_DE_FORCE_UNLOAD;
 #if DDLL_SMP
 	unlock_drv_list();
 #endif
-	for (j = 0; j < erts_max_ports; j++) {
-	    Port* prt = &erts_port[j];
-	    erts_smp_port_state_lock(prt);
-	    if (!(prt->status &  FREE_PORT_FLAGS) 
-		&& prt->drv_ptr->handle == dh) {
-		erts_smp_atomic_inc_nob(&prt->refc);
-#if DDLL_SMP
-		/* Extremely rare spinlock */
-		while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
-		       erts_smp_port_state_unlock(prt);
-		       erts_smp_port_state_lock(prt);
-	        }
-		erts_smp_port_state_unlock(prt);
-		erts_smp_mtx_lock(prt->lock);
-		if (!(prt->status & ERTS_PORT_SFLGS_DEAD)) {
-		    driver_failure_atom(j, "driver_unloaded");
-		}
-#else
-		driver_failure_atom(j, "driver_unloaded");
-#endif
-		erts_port_release(prt);
-	    }
-	    else erts_smp_port_state_unlock(prt);
-	}
+	kill_ports_driver_unloaded(dh);
 #if DDLL_SMP
 	lock_drv_list(); 
 #endif
@@ -1047,36 +1047,13 @@ void erts_ddll_proc_dead(Process *p, ErtsProcLocks plocks)
 	    }
 	    if (!left && drv->handle->port_count > 0) {
 		if (kill_ports) {
-		    int j;
 		    DE_Handle *dh = drv->handle;
 		    erts_ddll_reference_driver(dh);
 		    dh->status = ERL_DE_FORCE_UNLOAD;
 #if DDLL_SMP
 		    unlock_drv_list();
 #endif
-		    for (j = 0; j < erts_max_ports; j++) {
-			Port* prt = &erts_port[j];
-			erts_smp_port_state_lock(prt);
-			if (!(prt->status & FREE_PORT_FLAGS) &&
-			    prt->drv_ptr->handle == dh) {
-			    erts_smp_atomic_inc_nob(&prt->refc);
-#if DDLL_SMP
-			    while(prt->status & ERTS_PORT_SFLG_INITIALIZING) {
-				erts_smp_port_state_unlock(prt);
-				erts_smp_port_state_lock(prt);
-			    }
-			    erts_smp_port_state_unlock(prt);
-			    erts_smp_mtx_lock(prt->lock);
-			    if (!(prt->status & ERTS_PORT_SFLGS_DEAD)) {
-				driver_failure_atom(j, "driver_unloaded");
-			    }
-#else
-			    driver_failure_atom(j, "driver_unloaded");
-#endif
-			    erts_port_release(prt);
-			}
-			else erts_smp_port_state_unlock(prt);
-		    } 
+		    kill_ports_driver_unloaded(dh);
 #if DDLL_SMP
 		    lock_drv_list(); /* Needed for future list operations */
 #endif
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 874d1606fd..6b71eddc8b 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -2975,7 +2975,8 @@ static BIF_RETTYPE port_info(Process* p, Eterm portid, Eterm item)
 #ifndef ERTS_SMP
 	res = am_false;
 #else
-	if (prt->status & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK) {
+	if (erts_smp_atomic32_read_nob(&prt->state)
+	    & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK) {
 	    DECL_AM(port_level);
 	    ASSERT(prt->drv_ptr->flags
 		   & ERL_DRV_FLAG_USE_PORT_LOCKING);
diff --git a/erts/emulator/beam/erl_bif_port.c b/erts/emulator/beam/erl_bif_port.c
index 5525426824..1a5b05fcfc 100644
--- a/erts/emulator/beam/erl_bif_port.c
+++ b/erts/emulator/beam/erl_bif_port.c
@@ -164,7 +164,7 @@ do_port_command(Process *BIF_P, Eterm arg1, Eterm arg2, Eterm arg3,
 	ERTS_BIF_PREP_ERROR(res, BIF_P, EXC_NOTSUP);
     }
     else if (!(flags & ERTS_PORT_COMMAND_FLAG_FORCE)
-	     && p->status & ERTS_PORT_SFLG_PORT_BUSY) {
+	     && (erts_smp_atomic32_read_nob(&p->state) & ERTS_PORT_SFLG_PORT_BUSY)) {
 	if (flags & ERTS_PORT_COMMAND_FLAG_NOSUSPEND) {
 	    ERTS_BIF_PREP_RET(res, am_false);
 	}
@@ -637,11 +637,10 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_nump)
     erts_driver_t* driver;
     char* name_buf = NULL;
     SysDriverOpts opts;
-    int binary_io;
-    int soft_eof;
     Sint linebuf;
     Eterm edir = NIL;
     byte dir[MAXPATHLEN];
+    erts_aint32_t sflgs = 0;
 
     /* These are the defaults */
     opts.packet_bytes = 0;
@@ -655,8 +654,6 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_nump)
     opts.overlapped_io = 0; 
     opts.spawn_type = ERTS_SPAWN_ANY; 
     opts.argv = NULL;
-    binary_io = 0;
-    soft_eof = 0;
     linebuf = 0;
 
     *err_nump = 0;
@@ -748,13 +745,13 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_nump)
 	    } else if (*nargs == am_nouse_stdio) {
 		opts.use_stdio = 0;
 	    } else if (*nargs == am_binary) {
-		binary_io = 1;
+		sflgs |= ERTS_PORT_SFLG_BINARY_IO;
 	    } else if (*nargs == am_in) {
 		opts.read_write |= DO_READ;
 	    } else if (*nargs == am_out) {
 		opts.read_write |= DO_WRITE;
 	    } else if (*nargs == am_eof) {
-		soft_eof = 1;
+		sflgs |= ERTS_PORT_SFLG_SOFT_EOF;
 	    } else if (*nargs == am_hide) {
 		opts.hide_window = 1;
 	    } else if (*nargs == am_exit_status) {
@@ -951,19 +948,13 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_nump)
         trace_virtual_sched(p, am_in);
     }
 
-    if (binary_io) {
-	erts_port_status_bor_set(&erts_port[port_num],
-				 ERTS_PORT_SFLG_BINARY_IO);
-    }
-    if (soft_eof) {
-	erts_port_status_bor_set(&erts_port[port_num],
-				 ERTS_PORT_SFLG_SOFT_EOF);
-    }
     if (linebuf && erts_port[port_num].linebuf == NULL){
-	erts_port[port_num].linebuf = allocate_linebuf(linebuf); 
-	erts_port_status_bor_set(&erts_port[port_num],
-				 ERTS_PORT_SFLG_LINEBUF_IO);
+	erts_port[port_num].linebuf = allocate_linebuf(linebuf);
+	sflgs |= ERTS_PORT_SFLG_LINEBUF_IO;
     }
+
+    if (sflgs)
+	erts_smp_atomic32_read_bor_relb(&erts_port[port_num].state, sflgs);
  
  do_return:
     if (name_buf)
diff --git a/erts/emulator/beam/erl_bif_trace.c b/erts/emulator/beam/erl_bif_trace.c
index 3baac1572a..01d714d57f 100644
--- a/erts/emulator/beam/erl_bif_trace.c
+++ b/erts/emulator/beam/erl_bif_trace.c
@@ -680,7 +680,9 @@ Eterm trace_3(BIF_ALIST_3)
 		/* tracing of ports */
 		for (i = 0; i < erts_max_ports; i++) {
 		    Port *tracee_port = &erts_port[i];
-		    if (tracee_port->status & ERTS_PORT_SFLGS_DEAD) continue;
+		    erts_aint32_t state;
+		    state = erts_smp_atomic32_read_nob(&tracee_port->state);
+		    if (state & ERTS_PORT_SFLGS_DEAD) continue;
 		    if (tracer != NIL) {
 			if (tracee_port->id == tracer) continue;
 			if (port_already_traced(NULL, tracee_port, tracer)) continue;
diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 93122b8317..f64a7fa41a 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -1384,7 +1384,8 @@ setup_reference_table(void)
 
     /* Insert all ports */
     for (i = 0; i < erts_max_ports; i++) {
-	if (erts_port[i].status & ERTS_PORT_SFLGS_DEAD)
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&erts_port[i].state);
+	if (state & ERTS_PORT_SFLGS_DEAD)
 	    continue;
 
 	/* Insert links */
diff --git a/erts/emulator/beam/erl_port_task.c b/erts/emulator/beam/erl_port_task.c
index 86454fe1fa..3873dd8f99 100644
--- a/erts/emulator/beam/erl_port_task.c
+++ b/erts/emulator/beam/erl_port_task.c
@@ -51,7 +51,8 @@
 
 
 #define ERTS_PORT_TASK_INVALID_PORT(P, ID) \
-  ((erts_port_status_get((P)) & ERTS_PORT_SFLGS_DEAD) || (P)->id != (ID))
+  ((erts_smp_atomic32_read_acqb(&(P)->state) & ERTS_PORT_SFLGS_DEAD) \
+   || (P)->id != (ID))
 
 #define ERTS_PORT_IS_IN_RUNQ(RQ, P) \
   ((P)->sched.next || (P)->sched.prev || (RQ)->ports.start == (P))
@@ -615,7 +616,7 @@ erts_port_task_free_port(Port *pp)
     ErtsPortTaskQueue *ptqp;
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(pp));
-    ASSERT(!(pp->status & ERTS_PORT_SFLGS_DEAD));
+    ASSERT(!(erts_smp_atomic32_read_nob(&pp->state) & ERTS_PORT_SFLGS_DEAD));
     runq = erts_port_runq(pp);
     ASSERT(runq);
     ERTS_PT_CHK_PRES_PORTQ(runq, pp);
@@ -626,11 +627,13 @@ erts_port_task_free_port(Port *pp)
 	ErtsPortTask *ptp;
     enqueue_free:
 	ptp = port_task_alloc();
-	erts_smp_port_state_lock(pp);
-	pp->status &= ~ERTS_PORT_SFLG_CLOSING;
-	pp->status |= ERTS_PORT_SFLG_FREE_SCHEDULED;
+	erts_smp_port_minor_lock(pp);
+	erts_smp_atomic32_read_bset_relb(&pp->state,
+					 (ERTS_PORT_SFLG_CLOSING
+					  | ERTS_PORT_SFLG_FREE_SCHEDULED),
+					 ERTS_PORT_SFLG_FREE_SCHEDULED);
 	erts_may_save_closed_port(pp);
-	erts_smp_port_state_unlock(pp);
+	erts_smp_port_minor_unlock(pp);
 	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 1);
 	ptp->type = ERTS_PORT_TASK_FREE;
 	ptp->event = (ErlDrvEvent) -1;
@@ -648,11 +651,13 @@ erts_port_task_free_port(Port *pp)
 	    goto enqueue_free;
 	}
 	ASSERT(!pp->sched.taskq);
-	erts_smp_port_state_lock(pp);
-	pp->status &= ~ERTS_PORT_SFLG_CLOSING;
-	pp->status |= ERTS_PORT_SFLG_FREE_SCHEDULED;
+	erts_smp_port_minor_lock(pp);
+	erts_smp_atomic32_read_bset_relb(&pp->state,
+					 (ERTS_PORT_SFLG_CLOSING
+					  | ERTS_PORT_SFLG_FREE_SCHEDULED),
+					 ERTS_PORT_SFLG_FREE_SCHEDULED);
 	erts_may_save_closed_port(pp);
-	erts_smp_port_state_unlock(pp);
+	erts_smp_port_minor_unlock(pp);
 	erts_smp_atomic_dec_nob(&pp->refc); /* Not alive */
 	ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&pp->refc) > 0); /* Lock */
 	handle_remaining_tasks(runq, pp); /* May release runq lock */
@@ -766,7 +771,8 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	    erts_smp_runq_lock(runq);
 
 	    erts_unblock_fpe(fpe_was_unmasked);
-	    ASSERT(pp->status & ERTS_PORT_SFLG_FREE_SCHEDULED);
+	    ASSERT(erts_smp_atomic32_read_nob(&pp->state)
+		   & ERTS_PORT_SFLG_FREE_SCHEDULED);
 	    if (ptqp->first || (pp->sched.taskq && pp->sched.taskq->first))
 		handle_remaining_tasks(runq, pp);
 	    ASSERT(!ptqp->first
@@ -782,14 +788,15 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	    goto tasks_done;
 	case ERTS_PORT_TASK_TIMEOUT:
 	    reds += ERTS_PORT_REDS_TIMEOUT;
-	    if (!(pp->status & ERTS_PORT_SFLGS_DEAD)) {
+	    if (!(erts_smp_atomic32_read_nob(&pp->state) & ERTS_PORT_SFLGS_DEAD)) {
                 DTRACE_DRIVER(driver_timeout, pp);
 		(*pp->drv_ptr->timeout)((ErlDrvData) pp->drv_data);
             }
 	    break;
 	case ERTS_PORT_TASK_INPUT:
 	    reds += ERTS_PORT_REDS_INPUT;
-	    ASSERT((pp->status & ERTS_PORT_SFLGS_DEAD) == 0);
+	    ASSERT((erts_smp_atomic32_read_nob(&pp->state)
+		    & ERTS_PORT_SFLGS_DEAD) == 0);
             DTRACE_DRIVER(driver_ready_input, pp);
 	    /* NOTE some windows drivers use ->ready_input for input and output */
 	    (*pp->drv_ptr->ready_input)((ErlDrvData) pp->drv_data, ptp->event);
@@ -797,14 +804,16 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	    break;
 	case ERTS_PORT_TASK_OUTPUT:
 	    reds += ERTS_PORT_REDS_OUTPUT;
-	    ASSERT((pp->status & ERTS_PORT_SFLGS_DEAD) == 0);
+	    ASSERT((erts_smp_atomic32_read_nob(&pp->state)
+		    & ERTS_PORT_SFLGS_DEAD) == 0);
             DTRACE_DRIVER(driver_ready_output, pp);
 	    (*pp->drv_ptr->ready_output)((ErlDrvData) pp->drv_data, ptp->event);
 	    io_tasks_executed++;
 	    break;
 	case ERTS_PORT_TASK_EVENT:
 	    reds += ERTS_PORT_REDS_EVENT;
-	    ASSERT((pp->status & ERTS_PORT_SFLGS_DEAD) == 0);
+	    ASSERT((erts_smp_atomic32_read_nob(&pp->state)
+		    & ERTS_PORT_SFLGS_DEAD) == 0);
             DTRACE_DRIVER(driver_event, pp);
 	    (*pp->drv_ptr->event)((ErlDrvData) pp->drv_data, ptp->event, ptp->event_data);
 	    io_tasks_executed++;
@@ -819,7 +828,7 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	    break;
 	}
 
-	if ((pp->status & ERTS_PORT_SFLG_CLOSING)
+	if ((erts_smp_atomic32_read_nob(&pp->state) & ERTS_PORT_SFLG_CLOSING)
 	    && erts_is_port_ioq_empty(pp)) {
 	    reds += ERTS_PORT_REDS_TERMINATE;
 	    erts_terminate_port(pp);
@@ -870,7 +879,7 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	ErtsRunQueue *xrunq;
 #endif
 
-	ASSERT(!(pp->status & ERTS_PORT_SFLGS_DEAD));
+	ASSERT(!(erts_smp_atomic32_read_nob(&pp->state) & ERTS_PORT_SFLGS_DEAD));
 	ASSERT(pp->sched.taskq->first);
 
 #ifdef ERTS_SMP
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 79614c85db..6170fd1ec8 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -1486,29 +1486,29 @@ handle_reap_ports(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 	erts_smp_atomic32_set_nob(&erts_halt_progress, 1);
 	for (i = 0; i < erts_max_ports; i++) {
 	    Port *prt = &erts_port[i];
-	    erts_smp_port_state_lock(prt);
-	    if ((prt->status & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
-				| ERTS_PORT_SFLG_HALT))) {
-		erts_smp_port_state_unlock(prt);
+	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&prt->state);
+	    if (state & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
+			 | ERTS_PORT_SFLG_HALT))
 		continue;
-	    }
+	    erts_smp_port_minor_lock(prt);
 	    /* We need to set the halt flag - get the port lock */
 #ifdef ERTS_SMP
 	    erts_smp_atomic_inc_nob(&prt->refc);
 #endif
-	    erts_smp_port_state_unlock(prt);
+	    erts_smp_port_minor_unlock(prt);
 #ifdef ERTS_SMP
 	    erts_smp_mtx_lock(prt->lock);
 #endif
-	    if ((prt->status & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
-				| ERTS_PORT_SFLG_HALT))) {
+	    state = erts_smp_atomic32_read_acqb(&prt->state);
+	    if (state & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
+			 | ERTS_PORT_SFLG_HALT)) {
 		erts_port_release(prt);
 		continue;
 	    }
-	    erts_port_status_bor_set(prt, ERTS_PORT_SFLG_HALT);
+	    state = erts_smp_atomic32_read_bor_relb(&prt->state,
+						    ERTS_PORT_SFLG_HALT);
 	    erts_smp_atomic32_inc_nob(&erts_halt_progress);
-	    if (prt->status & (ERTS_PORT_SFLG_EXITING
-			       | ERTS_PORT_SFLG_CLOSING)) {
+	    if (state & (ERTS_PORT_SFLG_EXITING|ERTS_PORT_SFLG_CLOSING)) {
 		erts_port_release(prt);
 		continue;
 	    }
@@ -2885,12 +2885,12 @@ resume_run_queue(ErtsRunQueue *rq)
 
     erts_smp_runq_lock(rq);
 
-    (void) ERTS_RUNQ_FLGS_MASK_SET(rq,
-				   (ERTS_RUNQ_FLG_OUT_OF_WORK
-				    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK
-				    | ERTS_RUNQ_FLG_SUSPENDED),
-				   (ERTS_RUNQ_FLG_OUT_OF_WORK
-				    | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK));
+    (void) ERTS_RUNQ_FLGS_READ_BSET(rq,
+				    (ERTS_RUNQ_FLG_OUT_OF_WORK
+				     | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK
+				     | ERTS_RUNQ_FLG_SUSPENDED),
+				    (ERTS_RUNQ_FLG_OUT_OF_WORK
+				     | ERTS_RUNQ_FLG_HALFTIME_OUT_OF_WORK));
 
     rq->check_balance_reds = ERTS_RUNQ_CALL_CHECK_BALANCE_REDS;
     for (pix = 0; pix < ERTS_NO_PROC_PRIO_LEVELS; pix++) {
@@ -3912,7 +3912,7 @@ erts_fprintf(stderr, "--------------------------------\n");
 	ERTS_DBG_CHK_FULL_REDS_HISTORY(rq);
 
 	rq->out_of_work_count = 0;
-	(void) ERTS_RUNQ_FLGS_MASK_SET(rq, ERTS_RUNQ_FLGS_MIGRATION_INFO, flags);
+	(void) ERTS_RUNQ_FLGS_READ_BSET(rq, ERTS_RUNQ_FLGS_MIGRATION_INFO, flags);
 
 	rq->max_len = rq->len;
 	for (pix = 0; pix < ERTS_NO_PRIO_LEVELS; pix++) {
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index 17d1ff0bd6..22303973bf 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -205,32 +205,10 @@ extern int erts_sched_thread_suggested_stack_size;
     ((Uint32) erts_smp_atomic32_read_nob(&(RQ)->flags))
 #define ERTS_RUNQ_FLGS_GET_MB(RQ)					\
     ((Uint32) erts_smp_atomic32_read_mb(&(RQ)->flags))
-#define ERTS_RUNQ_FLGS_MASK_SET(RQ, MSK, FLGS)		  		\
-    ((Uint32) erts_smp_atomic32_mask_set_relb(&(RQ)->flags, 		\
-					      (erts_aint32_t) (MSK),	\
-					      (erts_aint32_t) (FLGS)))
-
-ERTS_GLB_INLINE erts_aint32_t
-erts_smp_atomic32_mask_set_relb(erts_smp_atomic32_t *a32p,
-				erts_aint32_t mask,
-				erts_aint32_t set);
-#if ERTS_GLB_INLINE_INCL_FUNC_DEF
-ERTS_GLB_INLINE erts_aint32_t
-erts_smp_atomic32_mask_set_relb(erts_smp_atomic32_t *a32p,
-				erts_aint32_t mask,
-				erts_aint32_t set)
-{
-    erts_aint32_t act = erts_smp_atomic32_read_nob(a32p);
-    while (1) {
-	erts_aint32_t exp = act;
-	erts_aint32_t new = exp & ~mask;
-	new |= (mask & set);
-	act = erts_smp_atomic32_cmpxchg_relb(a32p, new, exp);
-	if (act == exp)
-	    return act;
-    }
-}	
-#endif
+#define ERTS_RUNQ_FLGS_READ_BSET(RQ, MSK, FLGS)		  		\
+    ((Uint32) erts_smp_atomic32_read_bset_relb(&(RQ)->flags, 		\
+					       (erts_aint32_t) (MSK),	\
+					       (erts_aint32_t) (FLGS)))
 
 typedef enum {
     ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED,
diff --git a/erts/emulator/beam/erl_smp.h b/erts/emulator/beam/erl_smp.h
index a32e9d9d7c..34c90c0bda 100644
--- a/erts/emulator/beam/erl_smp.h
+++ b/erts/emulator/beam/erl_smp.h
@@ -274,6 +274,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_nob erts_atomic_read_band_nob
 #define erts_smp_atomic_xchg_nob erts_atomic_xchg_nob
 #define erts_smp_atomic_cmpxchg_nob erts_atomic_cmpxchg_nob
+#define erts_smp_atomic_read_bset_nob erts_atomic_read_bset_nob
 
 #define erts_smp_atomic_init_mb erts_atomic_init_mb
 #define erts_smp_atomic_set_mb erts_atomic_set_mb
@@ -288,6 +289,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_mb erts_atomic_read_band_mb
 #define erts_smp_atomic_xchg_mb erts_atomic_xchg_mb
 #define erts_smp_atomic_cmpxchg_mb erts_atomic_cmpxchg_mb
+#define erts_smp_atomic_read_bset_mb erts_atomic_read_bset_mb
 
 #define erts_smp_atomic_init_acqb erts_atomic_init_acqb
 #define erts_smp_atomic_set_acqb erts_atomic_set_acqb
@@ -302,6 +304,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_acqb erts_atomic_read_band_acqb
 #define erts_smp_atomic_xchg_acqb erts_atomic_xchg_acqb
 #define erts_smp_atomic_cmpxchg_acqb erts_atomic_cmpxchg_acqb
+#define erts_smp_atomic_read_bset_acqb erts_atomic_read_bset_acqb
 
 #define erts_smp_atomic_init_relb erts_atomic_init_relb
 #define erts_smp_atomic_set_relb erts_atomic_set_relb
@@ -316,6 +319,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_relb erts_atomic_read_band_relb
 #define erts_smp_atomic_xchg_relb erts_atomic_xchg_relb
 #define erts_smp_atomic_cmpxchg_relb erts_atomic_cmpxchg_relb
+#define erts_smp_atomic_read_bset_relb erts_atomic_read_bset_relb
 
 #define erts_smp_atomic_init_ddrb erts_atomic_init_ddrb
 #define erts_smp_atomic_set_ddrb erts_atomic_set_ddrb
@@ -330,6 +334,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_ddrb erts_atomic_read_band_ddrb
 #define erts_smp_atomic_xchg_ddrb erts_atomic_xchg_ddrb
 #define erts_smp_atomic_cmpxchg_ddrb erts_atomic_cmpxchg_ddrb
+#define erts_smp_atomic_read_bset_ddrb erts_atomic_read_bset_ddrb
 
 #define erts_smp_atomic_init_rb erts_atomic_init_rb
 #define erts_smp_atomic_set_rb erts_atomic_set_rb
@@ -344,6 +349,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_rb erts_atomic_read_band_rb
 #define erts_smp_atomic_xchg_rb erts_atomic_xchg_rb
 #define erts_smp_atomic_cmpxchg_rb erts_atomic_cmpxchg_rb
+#define erts_smp_atomic_read_bset_rb erts_atomic_read_bset_rb
 
 #define erts_smp_atomic_init_wb erts_atomic_init_wb
 #define erts_smp_atomic_set_wb erts_atomic_set_wb
@@ -358,6 +364,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_wb erts_atomic_read_band_wb
 #define erts_smp_atomic_xchg_wb erts_atomic_xchg_wb
 #define erts_smp_atomic_cmpxchg_wb erts_atomic_cmpxchg_wb
+#define erts_smp_atomic_read_bset_wb erts_atomic_read_bset_wb
 
 /* 32-bit atomics */
 
@@ -374,6 +381,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_nob erts_atomic32_read_band_nob
 #define erts_smp_atomic32_xchg_nob erts_atomic32_xchg_nob
 #define erts_smp_atomic32_cmpxchg_nob erts_atomic32_cmpxchg_nob
+#define erts_smp_atomic32_read_bset_nob erts_atomic32_read_bset_nob
 
 #define erts_smp_atomic32_init_mb erts_atomic32_init_mb
 #define erts_smp_atomic32_set_mb erts_atomic32_set_mb
@@ -388,6 +396,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_mb erts_atomic32_read_band_mb
 #define erts_smp_atomic32_xchg_mb erts_atomic32_xchg_mb
 #define erts_smp_atomic32_cmpxchg_mb erts_atomic32_cmpxchg_mb
+#define erts_smp_atomic32_read_bset_mb erts_atomic32_read_bset_mb
 
 #define erts_smp_atomic32_init_acqb erts_atomic32_init_acqb
 #define erts_smp_atomic32_set_acqb erts_atomic32_set_acqb
@@ -402,6 +411,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_acqb erts_atomic32_read_band_acqb
 #define erts_smp_atomic32_xchg_acqb erts_atomic32_xchg_acqb
 #define erts_smp_atomic32_cmpxchg_acqb erts_atomic32_cmpxchg_acqb
+#define erts_smp_atomic32_read_bset_acqb erts_atomic32_read_bset_acqb
 
 #define erts_smp_atomic32_init_relb erts_atomic32_init_relb
 #define erts_smp_atomic32_set_relb erts_atomic32_set_relb
@@ -416,6 +426,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_relb erts_atomic32_read_band_relb
 #define erts_smp_atomic32_xchg_relb erts_atomic32_xchg_relb
 #define erts_smp_atomic32_cmpxchg_relb erts_atomic32_cmpxchg_relb
+#define erts_smp_atomic32_read_bset_relb erts_atomic32_read_bset_relb
 
 #define erts_smp_atomic32_init_ddrb erts_atomic32_init_ddrb
 #define erts_smp_atomic32_set_ddrb erts_atomic32_set_ddrb
@@ -430,6 +441,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_ddrb erts_atomic32_read_band_ddrb
 #define erts_smp_atomic32_xchg_ddrb erts_atomic32_xchg_ddrb
 #define erts_smp_atomic32_cmpxchg_ddrb erts_atomic32_cmpxchg_ddrb
+#define erts_smp_atomic32_read_bset_ddrb erts_atomic32_read_bset_ddrb
 
 #define erts_smp_atomic32_init_rb erts_atomic32_init_rb
 #define erts_smp_atomic32_set_rb erts_atomic32_set_rb
@@ -444,6 +456,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_rb erts_atomic32_read_band_rb
 #define erts_smp_atomic32_xchg_rb erts_atomic32_xchg_rb
 #define erts_smp_atomic32_cmpxchg_rb erts_atomic32_cmpxchg_rb
+#define erts_smp_atomic32_read_bset_rb erts_atomic32_read_bset_rb
 
 #define erts_smp_atomic32_init_wb erts_atomic32_init_wb
 #define erts_smp_atomic32_set_wb erts_atomic32_set_wb
@@ -458,6 +471,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_wb erts_atomic32_read_band_wb
 #define erts_smp_atomic32_xchg_wb erts_atomic32_xchg_wb
 #define erts_smp_atomic32_cmpxchg_wb erts_atomic32_cmpxchg_wb
+#define erts_smp_atomic32_read_bset_wb erts_atomic32_read_bset_wb
 
 #else /* !ERTS_SMP */
 
@@ -513,6 +527,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_nob erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_nob erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_nob erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_nob erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_mb erts_no_atomic_set
 #define erts_smp_atomic_set_mb erts_no_atomic_set
@@ -527,6 +542,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_mb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_mb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_mb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_mb erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_acqb erts_no_atomic_set
 #define erts_smp_atomic_set_acqb erts_no_atomic_set
@@ -541,6 +557,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_acqb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_acqb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_acqb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_acqb erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_relb erts_no_atomic_set
 #define erts_smp_atomic_set_relb erts_no_atomic_set
@@ -555,6 +572,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_relb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_relb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_relb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_relb erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_ddrb erts_no_atomic_set
 #define erts_smp_atomic_set_ddrb erts_no_atomic_set
@@ -569,6 +587,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_ddrb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_ddrb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_ddrb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_ddrb erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_rb erts_no_atomic_set
 #define erts_smp_atomic_set_rb erts_no_atomic_set
@@ -583,6 +602,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_rb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_rb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_rb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_rb erts_no_atomic_read_bset
 
 #define erts_smp_atomic_init_wb erts_no_atomic_set
 #define erts_smp_atomic_set_wb erts_no_atomic_set
@@ -597,6 +617,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic_read_band_wb erts_no_atomic_read_band
 #define erts_smp_atomic_xchg_wb erts_no_atomic_xchg
 #define erts_smp_atomic_cmpxchg_wb erts_no_atomic_cmpxchg
+#define erts_smp_atomic_read_bset_wb erts_no_atomic_read_bset
 
 /* 32-bit atomics */
 
@@ -613,6 +634,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_nob erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_nob erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_nob erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_nob erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_mb erts_no_atomic32_set
 #define erts_smp_atomic32_set_mb erts_no_atomic32_set
@@ -627,6 +649,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_mb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_mb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_mb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_mb erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_acqb erts_no_atomic32_set
 #define erts_smp_atomic32_set_acqb erts_no_atomic32_set
@@ -641,6 +664,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_acqb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_acqb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_acqb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_acqb erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_relb erts_no_atomic32_set
 #define erts_smp_atomic32_set_relb erts_no_atomic32_set
@@ -655,6 +679,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_relb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_relb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_relb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_relb erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_ddrb erts_no_atomic32_set
 #define erts_smp_atomic32_set_ddrb erts_no_atomic32_set
@@ -669,6 +694,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_ddrb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_ddrb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_ddrb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_ddrb erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_rb erts_no_atomic32_set
 #define erts_smp_atomic32_set_rb erts_no_atomic32_set
@@ -683,6 +709,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_rb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_rb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_rb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_rb erts_no_atomic32_read_bset
 
 #define erts_smp_atomic32_init_wb erts_no_atomic32_set
 #define erts_smp_atomic32_set_wb erts_no_atomic32_set
@@ -697,6 +724,7 @@ ERTS_GLB_INLINE void erts_smp_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_smp_atomic32_read_band_wb erts_no_atomic32_read_band
 #define erts_smp_atomic32_xchg_wb erts_no_atomic32_xchg
 #define erts_smp_atomic32_cmpxchg_wb erts_no_atomic32_cmpxchg
+#define erts_smp_atomic32_read_bset_wb erts_no_atomic32_read_bset
 
 #endif /* !ERTS_SMP */
 
diff --git a/erts/emulator/beam/erl_threads.h b/erts/emulator/beam/erl_threads.h
index 17628286bc..0e759a1eec 100644
--- a/erts/emulator/beam/erl_threads.h
+++ b/erts/emulator/beam/erl_threads.h
@@ -533,6 +533,9 @@ ERTS_GLB_INLINE erts_aint_t erts_no_atomic_xchg(erts_no_atomic_t *xchgp,
 ERTS_GLB_INLINE erts_aint_t erts_no_atomic_cmpxchg(erts_no_atomic_t *xchgp,
 						   erts_aint_t new,
 						   erts_aint_t expected);
+ERTS_GLB_INLINE erts_aint_t erts_no_atomic_read_bset(erts_no_atomic_t *var,
+						     erts_aint_t mask,
+						     erts_aint_t set);
 ERTS_GLB_INLINE void erts_no_atomic32_set(erts_no_atomic32_t *var,
 					  erts_aint32_t i);
 ERTS_GLB_INLINE erts_aint32_t erts_no_atomic32_read(erts_no_atomic32_t *var);
@@ -553,6 +556,9 @@ ERTS_GLB_INLINE erts_aint32_t erts_no_atomic32_xchg(erts_no_atomic32_t *xchgp,
 ERTS_GLB_INLINE erts_aint32_t erts_no_atomic32_cmpxchg(erts_no_atomic32_t *xchgp,
 						       erts_aint32_t new,
 						       erts_aint32_t expected);
+ERTS_GLB_INLINE erts_aint32_t erts_no_atomic32_read_bset(erts_no_atomic32_t *var,
+							 erts_aint32_t mask,
+							 erts_aint32_t set);
 
 ERTS_GLB_INLINE void erts_spinlock_init_x_opt(erts_spinlock_t *lock,
 					      char *name,
@@ -612,6 +618,78 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 
 #ifdef USE_THREADS
 
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_nob(erts_atomic_t *var,
+			  erts_aint_t mask,
+			  erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_ddrb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_rb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_wb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_acqb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_relb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set);
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_mb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_nob(erts_atomic32_t *var,
+			    erts_aint32_t mask,
+			    erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_ddrb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_rb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_wb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_acqb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_relb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set);
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_mb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set);
+
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+#define ERTS_ATOMIC_BSET_IMPL__(Type, ReadOp, CmpxchgOp, VarP, Mask, Set) \
+do {									\
+    Type act = ReadOp((VarP));						\
+    while (1) {								\
+	Type exp = act;							\
+	Type new = exp & ~(Mask);					\
+	new |= ((Mask) & (Set));					\
+	act = CmpxchgOp((VarP), new, exp);				\
+	if (act == exp)							\
+	    return act;							\
+    }									\
+} while (0)
+#endif
+
 /*
  * See "Documentation of atomics and memory barriers" at the top
  * of this file for info on atomics.
@@ -670,6 +748,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_nob ethr_atomic_xchg
 #define erts_atomic_cmpxchg_nob ethr_atomic_cmpxchg
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_nob(erts_atomic_t *var,
+			  erts_aint_t mask,
+			  erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_mb ethr_atomic_init_mb
 #define erts_atomic_set_mb ethr_atomic_set_mb
 #define erts_atomic_read_mb ethr_atomic_read_mb
@@ -684,6 +775,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_mb ethr_atomic_xchg_mb
 #define erts_atomic_cmpxchg_mb ethr_atomic_cmpxchg_mb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_mb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_mb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_acqb ethr_atomic_init_acqb
 #define erts_atomic_set_acqb ethr_atomic_set_acqb
 #define erts_atomic_read_acqb ethr_atomic_read_acqb
@@ -698,6 +802,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_acqb ethr_atomic_xchg_acqb
 #define erts_atomic_cmpxchg_acqb ethr_atomic_cmpxchg_acqb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_acqb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_acqb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_relb ethr_atomic_init_relb
 #define erts_atomic_set_relb ethr_atomic_set_relb
 #define erts_atomic_read_relb ethr_atomic_read_relb
@@ -712,6 +829,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_relb ethr_atomic_xchg_relb
 #define erts_atomic_cmpxchg_relb ethr_atomic_cmpxchg_relb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_relb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_relb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_ddrb ethr_atomic_init_ddrb
 #define erts_atomic_set_ddrb ethr_atomic_set_ddrb
 #define erts_atomic_read_ddrb ethr_atomic_read_ddrb
@@ -726,6 +856,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_ddrb ethr_atomic_xchg_ddrb
 #define erts_atomic_cmpxchg_ddrb ethr_atomic_cmpxchg_ddrb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_ddrb(erts_atomic_t *var,
+			   erts_aint_t mask,
+			   erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_ddrb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_rb ethr_atomic_init_rb
 #define erts_atomic_set_rb ethr_atomic_set_rb
 #define erts_atomic_read_rb ethr_atomic_read_rb
@@ -740,6 +883,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_rb ethr_atomic_xchg_rb
 #define erts_atomic_cmpxchg_rb ethr_atomic_cmpxchg_rb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_rb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_rb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic_init_wb ethr_atomic_init_wb
 #define erts_atomic_set_wb ethr_atomic_set_wb
 #define erts_atomic_read_wb ethr_atomic_read_wb
@@ -754,6 +910,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_xchg_wb ethr_atomic_xchg_wb
 #define erts_atomic_cmpxchg_wb ethr_atomic_cmpxchg_wb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint_t
+erts_atomic_read_bset_wb(erts_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint_t,
+			    ethr_atomic_read,
+			    ethr_atomic_cmpxchg_wb,
+			    var, mask, set);
+}
+#endif
+
 /* 32-bit atomics */
 
 #define erts_atomic32_init_nob ethr_atomic32_init
@@ -770,6 +939,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_nob ethr_atomic32_xchg
 #define erts_atomic32_cmpxchg_nob ethr_atomic32_cmpxchg
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_nob(erts_atomic32_t *var,
+			    erts_aint32_t mask,
+			    erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_mb ethr_atomic32_init_mb
 #define erts_atomic32_set_mb ethr_atomic32_set_mb
 #define erts_atomic32_read_mb ethr_atomic32_read_mb
@@ -784,6 +966,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_mb ethr_atomic32_xchg_mb
 #define erts_atomic32_cmpxchg_mb ethr_atomic32_cmpxchg_mb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_mb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_mb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_acqb ethr_atomic32_init_acqb
 #define erts_atomic32_set_acqb ethr_atomic32_set_acqb
 #define erts_atomic32_read_acqb ethr_atomic32_read_acqb
@@ -798,6 +993,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_acqb ethr_atomic32_xchg_acqb
 #define erts_atomic32_cmpxchg_acqb ethr_atomic32_cmpxchg_acqb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_acqb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_acqb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_relb ethr_atomic32_init_relb
 #define erts_atomic32_set_relb ethr_atomic32_set_relb
 #define erts_atomic32_read_relb ethr_atomic32_read_relb
@@ -812,6 +1020,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_relb ethr_atomic32_xchg_relb
 #define erts_atomic32_cmpxchg_relb ethr_atomic32_cmpxchg_relb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_relb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_relb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_ddrb ethr_atomic32_init_ddrb
 #define erts_atomic32_set_ddrb ethr_atomic32_set_ddrb
 #define erts_atomic32_read_ddrb ethr_atomic32_read_ddrb
@@ -826,6 +1047,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_ddrb ethr_atomic32_xchg_ddrb
 #define erts_atomic32_cmpxchg_ddrb ethr_atomic32_cmpxchg_ddrb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_ddrb(erts_atomic32_t *var,
+			     erts_aint32_t mask,
+			     erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_ddrb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_rb ethr_atomic32_init_rb
 #define erts_atomic32_set_rb ethr_atomic32_set_rb
 #define erts_atomic32_read_rb ethr_atomic32_read_rb
@@ -840,6 +1074,19 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_rb ethr_atomic32_xchg_rb
 #define erts_atomic32_cmpxchg_rb ethr_atomic32_cmpxchg_rb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_rb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_rb,
+			    var, mask, set);
+}
+#endif
+
 #define erts_atomic32_init_wb ethr_atomic32_init_wb
 #define erts_atomic32_set_wb ethr_atomic32_set_wb
 #define erts_atomic32_read_wb ethr_atomic32_read_wb
@@ -854,6 +1101,21 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_xchg_wb ethr_atomic32_xchg_wb
 #define erts_atomic32_cmpxchg_wb ethr_atomic32_cmpxchg_wb
 
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+ERTS_GLB_INLINE erts_aint32_t
+erts_atomic32_read_bset_wb(erts_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set)
+{
+    ERTS_ATOMIC_BSET_IMPL__(erts_aint32_t,
+			    ethr_atomic32_read,
+			    ethr_atomic32_cmpxchg_wb,
+			    var, mask, set);
+}
+#endif
+
+#undef ERTS_ATOMIC_BSET_IMPL__
+
 #else /* !USE_THREADS */
 
 /* Double word size atomics */
@@ -908,6 +1170,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_nob erts_no_atomic_read_band
 #define erts_atomic_xchg_nob erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_nob erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_nob erts_no_atomic_read_bset
 
 #define erts_atomic_init_mb erts_no_atomic_set
 #define erts_atomic_set_mb erts_no_atomic_set
@@ -922,6 +1185,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_mb erts_no_atomic_read_band
 #define erts_atomic_xchg_mb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_mb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_mb erts_no_atomic_read_bset
 
 #define erts_atomic_init_acqb erts_no_atomic_set
 #define erts_atomic_set_acqb erts_no_atomic_set
@@ -936,6 +1200,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_acqb erts_no_atomic_read_band
 #define erts_atomic_xchg_acqb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_acqb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_acqb erts_no_atomic_read_bset
 
 #define erts_atomic_init_relb erts_no_atomic_set
 #define erts_atomic_set_relb erts_no_atomic_set
@@ -950,6 +1215,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_relb erts_no_atomic_read_band
 #define erts_atomic_xchg_relb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_relb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_relb erts_no_atomic_read_bset
 
 #define erts_atomic_init_ddrb erts_no_atomic_set
 #define erts_atomic_set_ddrb erts_no_atomic_set
@@ -964,6 +1230,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_ddrb erts_no_atomic_read_band
 #define erts_atomic_xchg_ddrb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_ddrb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_ddrb erts_no_atomic_read_bset
 
 #define erts_atomic_init_rb erts_no_atomic_set
 #define erts_atomic_set_rb erts_no_atomic_set
@@ -978,6 +1245,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_rb erts_no_atomic_read_band
 #define erts_atomic_xchg_rb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_rb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_rb erts_no_atomic_read_bset
 
 #define erts_atomic_init_wb erts_no_atomic_set
 #define erts_atomic_set_wb erts_no_atomic_set
@@ -992,6 +1260,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic_read_band_wb erts_no_atomic_read_band
 #define erts_atomic_xchg_wb erts_no_atomic_xchg
 #define erts_atomic_cmpxchg_wb erts_no_atomic_cmpxchg
+#define erts_atomic_read_bset_wb erts_no_atomic_read_bset
 
 /* 32-bit atomics */
 
@@ -1008,6 +1277,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_nob erts_no_atomic32_read_band
 #define erts_atomic32_xchg_nob erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_nob erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_nob erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_mb erts_no_atomic32_set
 #define erts_atomic32_set_mb erts_no_atomic32_set
@@ -1022,6 +1292,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_mb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_mb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_mb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_mb erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_acqb erts_no_atomic32_set
 #define erts_atomic32_set_acqb erts_no_atomic32_set
@@ -1036,6 +1307,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_acqb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_acqb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_acqb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_acqb erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_relb erts_no_atomic32_set
 #define erts_atomic32_set_relb erts_no_atomic32_set
@@ -1050,6 +1322,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_relb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_relb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_relb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_relb erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_ddrb erts_no_atomic32_set
 #define erts_atomic32_set_ddrb erts_no_atomic32_set
@@ -1064,6 +1337,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_ddrb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_ddrb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_ddrb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_ddrb erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_rb erts_no_atomic32_set
 #define erts_atomic32_set_rb erts_no_atomic32_set
@@ -1078,6 +1352,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_rb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_rb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_rb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_rb erts_no_atomic32_read_bset
 
 #define erts_atomic32_init_wb erts_no_atomic32_set
 #define erts_atomic32_set_wb erts_no_atomic32_set
@@ -1092,6 +1367,7 @@ ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig);
 #define erts_atomic32_read_band_wb erts_no_atomic32_read_band
 #define erts_atomic32_xchg_wb erts_no_atomic32_xchg
 #define erts_atomic32_cmpxchg_wb erts_no_atomic32_cmpxchg
+#define erts_atomic32_read_bset_wb erts_no_atomic32_read_bset
 
 #endif /* !USE_THREADS */
 
@@ -1856,6 +2132,16 @@ erts_no_atomic_cmpxchg(erts_no_atomic_t *xchgp,
     return old;
 }
 
+ERTS_GLB_INLINE erts_aint_t
+erts_no_atomic_read_bset(erts_no_atomic_t *var,
+			 erts_aint_t mask,
+			 erts_aint_t set)
+{
+    erts_aint_t old = *var;
+    *var |= (mask & set);
+    return old;
+}
+
 /* atomic32 */
 
 ERTS_GLB_INLINE void
@@ -1943,6 +2229,16 @@ erts_no_atomic32_cmpxchg(erts_no_atomic32_t *xchgp,
     return old;
 }
 
+ERTS_GLB_INLINE erts_aint32_t
+erts_no_atomic32_read_bset(erts_no_atomic32_t *var,
+			   erts_aint32_t mask,
+			   erts_aint32_t set)
+{
+    erts_aint32_t old = *var;
+    *var |= (mask & set);
+    return old;
+}
+
 /* spinlock */
 
 ERTS_GLB_INLINE void
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 86f8e3890b..5386e0eb4e 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -183,7 +183,7 @@ struct port {
     ErtsProcList *suspended;	 /* List of suspended processes. */
     LineBuf *linebuf;            /* Buffer to hold data not ready for
 				    process to get (line oriented I/O)*/
-    Uint32 status;		 /* Status and type flags */
+    erts_smp_atomic32_t state;	 /* Status and type flags */
     int control_flags;		 /* Flags for port_control()  */
     erts_aint32_t snapshot;      /* Next snapshot that port should be part of */
     struct reg_proc *reg;
@@ -1202,8 +1202,8 @@ void erts_smp_xports_unlock(Port *);
 int erts_lc_is_port_locked(Port *);
 #endif
 
-ERTS_GLB_INLINE void erts_smp_port_state_lock(Port*);
-ERTS_GLB_INLINE void erts_smp_port_state_unlock(Port*);
+ERTS_GLB_INLINE void erts_smp_port_minor_lock(Port*);
+ERTS_GLB_INLINE void erts_smp_port_minor_unlock(Port*);
 
 ERTS_GLB_INLINE int erts_smp_port_trylock(Port *prt);
 ERTS_GLB_INLINE void erts_smp_port_lock(Port *prt);
@@ -1212,7 +1212,7 @@ ERTS_GLB_INLINE void erts_smp_port_unlock(Port *prt);
 #if ERTS_GLB_INLINE_INCL_FUNC_DEF
 
 ERTS_GLB_INLINE void
-erts_smp_port_state_lock(Port* prt)
+erts_smp_port_minor_lock(Port* prt)
 {
 #ifdef ERTS_SMP
     erts_smp_spin_lock(&prt->state_lck);
@@ -1220,7 +1220,7 @@ erts_smp_port_state_lock(Port* prt)
 }
 
 ERTS_GLB_INLINE void
-erts_smp_port_state_unlock(Port *prt)
+erts_smp_port_minor_unlock(Port *prt)
 {
 #ifdef ERTS_SMP
     erts_smp_spin_unlock(&prt->state_lck);
@@ -1274,8 +1274,10 @@ erts_smp_port_unlock(Port *prt)
 #endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
 
 
-#define ERTS_INVALID_PORT_OPT(PP, ID, FLGS) \
-  (!(PP) || ((PP)->status & (FLGS)) || (PP)->id != (ID))
+#define ERTS_INVALID_PORT_OPT(PP, ID, FLGS)			\
+    (!(PP)							\
+     || (erts_smp_atomic32_read_nob(&(PP)->state) & (FLGS))	\
+     || (PP)->id != (ID))
 
 /* port lookup */
 
@@ -1300,16 +1302,11 @@ Port *erts_de2port(DistEntry *, Process *, ErtsProcLocks);
 
 ERTS_GLB_INLINE Port*erts_id2port_sflgs(Eterm, Process *, ErtsProcLocks, Uint32);
 ERTS_GLB_INLINE void erts_port_release(Port *);
-ERTS_GLB_INLINE Port*erts_drvport2port(ErlDrvPort);
+ERTS_GLB_INLINE Port*erts_drvport2port(ErlDrvPort, erts_aint32_t *);
 ERTS_GLB_INLINE Port*erts_drvportid2port(Eterm);
 ERTS_GLB_INLINE Uint32 erts_portid2status(Eterm id);
 ERTS_GLB_INLINE int erts_is_port_alive(Eterm id);
 ERTS_GLB_INLINE int erts_is_valid_tracer_port(Eterm id);
-ERTS_GLB_INLINE void erts_port_status_bandor_set(Port *, Uint32, Uint32);
-ERTS_GLB_INLINE void erts_port_status_band_set(Port *, Uint32);
-ERTS_GLB_INLINE void erts_port_status_bor_set(Port *, Uint32);
-ERTS_GLB_INLINE void erts_port_status_set(Port *, Uint32);
-ERTS_GLB_INLINE Uint32 erts_port_status_get(Port *);
 
 #if ERTS_GLB_INLINE_INCL_FUNC_DEF
 
@@ -1326,14 +1323,14 @@ erts_id2port_sflgs(Eterm id, Process *c_p, ErtsProcLocks c_p_locks, Uint32 sflgs
 
     prt = &erts_port[internal_port_index(id)];
 
-    erts_smp_port_state_lock(prt);
+    erts_smp_port_minor_lock(prt);
     if (ERTS_INVALID_PORT_OPT(prt, id, sflgs)) {
-	erts_smp_port_state_unlock(prt);
+	erts_smp_port_minor_unlock(prt);
 	prt = NULL;
     }
     else {
 	erts_smp_atomic_inc_nob(&prt->refc);
-	erts_smp_port_state_unlock(prt);
+	erts_smp_port_minor_unlock(prt);
 
 #ifdef ERTS_SMP
  	if (no_proc_locks)
@@ -1347,8 +1344,8 @@ erts_id2port_sflgs(Eterm id, Process *c_p, ErtsProcLocks c_p_locks, Uint32 sflgs
 
 	/* The id may not have changed... */
 	ERTS_SMP_LC_ASSERT(prt->id == id);
-	/* ... but status may have... */
-	if (prt->status & sflgs) {
+	/* ... but state may have... */
+	if (erts_smp_atomic32_read_nob(&prt->state) & sflgs) {
 	    erts_smp_port_unlock(prt); /* Also decrements refc... */
 	    prt = NULL;
 	}
@@ -1366,14 +1363,18 @@ erts_port_release(Port *prt)
 }
 
 ERTS_GLB_INLINE Port*
-erts_drvport2port(ErlDrvPort drvport)
+erts_drvport2port(ErlDrvPort drvport, erts_aint32_t *statep)
 {
     int ix = (int) drvport;
+    erts_aint32_t state;
     if (ix < 0 || erts_max_ports <= ix)
 	return NULL;
-    if (erts_port[ix].status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
+    state = erts_smp_atomic32_read_nob(&erts_port[ix].state);
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
 	return NULL;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(&erts_port[ix]));
+    if (statep)
+	*statep = state;
     return &erts_port[ix];
 }
 
@@ -1381,12 +1382,14 @@ ERTS_GLB_INLINE Port*
 erts_drvportid2port(Eterm id)
 {
     int ix;
+    erts_aint32_t state;
     if (is_not_internal_port(id))
 	return NULL;
     ix = (int) internal_port_index(id);
     if (erts_max_ports <= ix)
 	return NULL;
-    if (erts_port[ix].status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
+    state = erts_smp_atomic32_read_nob(&erts_port[ix].state);
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
 	return NULL;
     if (erts_port[ix].id != id)
 	return NULL;
@@ -1400,17 +1403,14 @@ erts_portid2status(Eterm id)
     if (is_not_internal_port(id))
 	return ERTS_PORT_SFLG_INVALID;
     else {
-	Uint32 status;
+	erts_aint32_t state;
 	int ix = internal_port_index(id);
 	if (erts_max_ports <= ix)
 	    return ERTS_PORT_SFLG_INVALID;
-	erts_smp_port_state_lock(&erts_port[ix]);
-	if (erts_port[ix].id == id)
-	    status = erts_port[ix].status;
-	else
-	    status = ERTS_PORT_SFLG_INVALID;
-	erts_smp_port_state_unlock(&erts_port[ix]);
-	return status;
+	state = erts_smp_atomic32_read_ddrb(&erts_port[ix].state);
+	if (erts_port[ix].id != id)
+	    return ERTS_PORT_SFLG_INVALID;
+	return state;
     }
 }
 
@@ -1426,50 +1426,6 @@ erts_is_valid_tracer_port(Eterm id)
 {
     return !(erts_portid2status(id) & ERTS_PORT_SFLGS_INVALID_TRACER_LOOKUP);
 }
-
-ERTS_GLB_INLINE void erts_port_status_bandor_set(Port *prt,
-						 Uint32 band_status,
-						 Uint32 bor_status)
-{
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    erts_smp_port_state_lock(prt);
-    prt->status &= band_status;
-    prt->status |= bor_status;
-    erts_smp_port_state_unlock(prt);
-}
-
-ERTS_GLB_INLINE void erts_port_status_band_set(Port *prt, Uint32 status)
-{
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    erts_smp_port_state_lock(prt);
-    prt->status &= status;
-    erts_smp_port_state_unlock(prt);
-}
-
-ERTS_GLB_INLINE void erts_port_status_bor_set(Port *prt, Uint32 status)
-{
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    erts_smp_port_state_lock(prt);
-    prt->status |= status;
-    erts_smp_port_state_unlock(prt);
-}
-
-ERTS_GLB_INLINE void erts_port_status_set(Port *prt, Uint32 status)
-{
-    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
-    erts_smp_port_state_lock(prt);
-    prt->status = status;
-    erts_smp_port_state_unlock(prt);
-}
-
-ERTS_GLB_INLINE Uint32 erts_port_status_get(Port *prt)
-{
-    Uint32 res;
-    erts_smp_port_state_lock(prt);
-    res = prt->status;
-    erts_smp_port_state_unlock(prt);
-    return res;
-}
 #endif /* #if ERTS_GLB_INLINE_INCL_FUNC_DEF */
 
 /* erl_drv_thread.c */
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index f9e1b62f14..00ecf1fca2 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -90,35 +90,35 @@ static ERTS_INLINE ErlIOQueue*
 drvport2ioq(ErlDrvPort drvport)
 {
     int ix = (int) drvport;
-    Uint32 status;
+    erts_aint32_t state;
 
     if (ix < 0 || erts_max_ports <= ix)
 	return NULL;
 
+    state = erts_smp_atomic32_read_nob(&erts_port[ix].state);
+
+#ifdef ERTS_ENABLE_LOCK_CHECK
+
     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_LC_ASSERT((state & 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);
+#endif
+
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP)
+	return NULL;
+    else
+	return &erts_port[ix].ioq;
 }
 
 static ERTS_INLINE int
@@ -216,7 +216,7 @@ kill_port(Port *pp)
 {
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(pp));
     erts_port_task_free_port(pp);
-    ASSERT(pp->status & ERTS_PORT_SFLGS_DEAD);
+    ASSERT(erts_smp_atomic32_read_nob(&pp->state) & ERTS_PORT_SFLGS_DEAD);
 }
 
 #ifdef ERTS_SMP
@@ -242,27 +242,32 @@ get_free_port(void)
 
     erts_smp_spin_lock(&get_free_port_lck);
     num = last_port_num + 1;
-    for (;; ++num) {	
+    for (;; ++num) {
+	erts_aint32_t act;
+
 	port = &erts_port[num & erts_port_tab_index_mask];
 
-	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;
+	act = erts_smp_atomic32_read_nob(&port->state);
+
+	while (act & ERTS_PORT_SFLG_FREE) {
+	    erts_aint32_t exp = act;
+	    act = erts_smp_atomic32_cmpxchg_relb(&port->state,
+						 ERTS_PORT_SFLG_INITIALIZING,
+						 exp);
+	    if (act == exp) {
+		last_port_num = num;
+		erts_smp_spin_unlock(&get_free_port_lck);
+		ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&port->refc) == 0);
+		erts_smp_atomic_set_nob(&port->refc, 2); /* Port alive + lock */
+		return num & port_num_mask;
+	    }
 	}
-	erts_smp_port_state_unlock(port);
 
 	if (--tries == 0) {
 	    erts_smp_spin_unlock(&get_free_port_lck);
 	    return -1;
 	}
     }
-    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;
 }
 
 /*
@@ -284,13 +289,12 @@ erts_test_next_port(int set, Uint next)
 	
 	Port* port = &erts_port[num & erts_port_tab_index_mask];
 
-	erts_smp_port_state_lock(port);
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&port->state);
 
-	if (port->status & ERTS_PORT_SFLG_FREE) {	   
+	if (state & ERTS_PORT_SFLG_FREE) {	   
 	    last_port_num = num - 1;
 	    res = num & port_num_mask;
 	}
-	erts_smp_port_state_unlock(port);
     }
     erts_smp_spin_unlock(&get_free_port_lck);
     return res;
@@ -326,38 +330,37 @@ void
 port_cleanup(Port *prt)
 {
 #ifdef ERTS_SMP
-    Uint32 port_specific;
     erts_smp_mtx_t *mtx;
 #endif
+#if defined(ERTS_SMP) || defined(ERTS_ENABLE_LOCK_CHECK)
+    erts_aint32_t state = erts_smp_atomic32_read_nob(&prt->state);
+#endif
     erts_driver_t *driver;
 
-    erts_smp_port_state_lock(prt);
-
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
     driver = prt->drv_ptr;
     prt->drv_ptr = NULL;
     ASSERT(driver);
 
-    ASSERT(prt->status & ERTS_PORT_SFLG_FREE_SCHEDULED);
-    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&prt->refc) == 0);
+    ERTS_LC_ASSERT(state & ERTS_PORT_SFLG_FREE_SCHEDULED);
+    ERTS_LC_ASSERT(state & ERTS_PORT_SFLG_PORT_DEBUG);
+    ERTS_LC_ASSERT(!(state & ERTS_PORT_SFLG_FREE));
 
-    ASSERT(prt->status & ERTS_PORT_SFLG_PORT_DEBUG);
-    ASSERT(!(prt->status & ERTS_PORT_SFLG_FREE));
-    prt->status = ERTS_PORT_SFLG_FREE;
+    ERTS_LC_ASSERT(erts_smp_atomic_read_nob(&prt->refc) == 0);
 
 #ifdef ERTS_SMP
-
-    port_specific = (prt->status & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK);
-
     mtx = prt->lock;
     ASSERT(mtx);
 
     prt->lock = NULL;
 
-    erts_smp_port_state_unlock(prt);    
     erts_smp_mtx_unlock(mtx);
+#endif
 
-    if (port_specific) {
+    erts_smp_atomic32_set_relb(&prt->state, ERTS_PORT_SFLG_FREE);
+
+#ifdef ERTS_SMP
+    if (state & ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK) {
 	erts_smp_mtx_destroy(mtx);
 	erts_free(ERTS_ALC_T_PORT_LOCK, mtx);
     }
@@ -422,13 +425,13 @@ static void stopq(Port* prt)
 
 static void
 setup_port(Port* prt, Eterm pid, erts_driver_t *driver, 
-	   ErlDrvData drv_data, char *name, Uint32 xstatus)
+	   ErlDrvData drv_data, char *name, erts_aint32_t xstate)
 {
     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;
+    xstate |= ERTS_PORT_SFLG_PORT_DEBUG;
 #endif
     ASSERT(runq);
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
@@ -437,8 +440,6 @@ setup_port(Port* prt, Eterm pid, erts_driver_t *driver,
     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->status = ERTS_PORT_SFLG_CONNECTED | xstatus;
     prt->snapshot = erts_smp_atomic32_read_nob(&erts_ports_snapshot);    
     old_name = prt->name;
     prt->name = new_name;
@@ -447,7 +448,8 @@ setup_port(Port* prt, Eterm pid, erts_driver_t *driver,
 #endif
     ASSERT(!prt->drv_ptr);
     prt->drv_ptr = driver;
-    erts_smp_port_state_unlock(prt);
+    erts_smp_atomic32_set_relb(&prt->state,
+			       ERTS_PORT_SFLG_CONNECTED | xstate);
     erts_smp_runq_unlock(runq);
 #ifdef ERTS_SMP
     ASSERT(!prt->xports);
@@ -492,7 +494,7 @@ erts_wake_process_later(Port *prt, Process *process)
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
 
-    if (prt->status & ERTS_PORT_SFLGS_DEAD)
+    if (erts_smp_atomic32_read_nob(&prt->state) & ERTS_PORT_SFLGS_DEAD)
 	return;
 
     for (p = &(prt->suspended); *p != NULL; p = &((*p)->next))
@@ -522,7 +524,7 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
     int port_num;
     int port_ix;
     ErlDrvData drv_data = 0;
-    Uint32 xstatus = 0;
+    erts_aint32_t xstate = 0;
     Port *port;
     int fpe_was_unmasked;
 
@@ -601,11 +603,9 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
 	    *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);
+	erts_smp_atomic32_set_relb(&port->state, ERTS_PORT_SFLG_FREE);
 	return -3;
     }
 
@@ -623,7 +623,7 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
 	erts_smp_mtx_init_x(port->lock,
 			    "port_lock",
 			    port->id);
-	xstatus |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
+	xstate |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
     }
 #endif
 
@@ -637,7 +637,7 @@ erts_open_driver(erts_driver_t* driver,	/* Pointer to driver. */
     erts_smp_mtx_lock(port->lock);
 #endif
 
-    setup_port(port, pid, driver, drv_data, name, xstatus);
+    setup_port(port, pid, driver, drv_data, name, xstate);
     
     if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
 	trace_port_open(port,
@@ -737,11 +737,11 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
     Process *rp;
     int port_num;
     Eterm port_id;
-    Uint32 xstatus = 0;
+    erts_aint32_t xstate = 0;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-    creator_port = erts_drvport2port(creator_port_ix);
+    creator_port = erts_drvport2port(creator_port_ix, NULL);
     if (!creator_port)
 	return (ErlDrvTermData) -1;
 
@@ -780,7 +780,7 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
 	port->lock = erts_alloc(ERTS_ALC_T_PORT_LOCK,
 					      sizeof(erts_smp_mtx_t));
 	erts_smp_mtx_init_locked_x(port->lock, "port_lock", port_id);
-	xstatus |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
+	xstate |= ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK;
     }
 
 #endif
@@ -793,7 +793,7 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(port));
 
-    setup_port(port, pid, driver, drv_data, name, xstatus);
+    setup_port(port, pid, driver, drv_data, name, xstate);
     port->id = port_id;
 
     erts_add_link(&(port->nlinks), LINK_PID, pid);
@@ -1349,7 +1349,7 @@ void init_io(void)
 	ERTS_TRACE_FLAGS(&erts_port[i]) = 0;
 
 	erts_port[i].drv_ptr = NULL;
-	erts_port[i].status = ERTS_PORT_SFLG_FREE;
+	erts_smp_atomic32_init_nob(&erts_port[i].state, ERTS_PORT_SFLG_FREE);
 	erts_port[i].name = NULL;
 	erts_port[i].nlinks = NULL;
 	erts_port[i].monitors = NULL;
@@ -1593,7 +1593,7 @@ 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)
 {
@@ -1611,10 +1611,11 @@ 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;
@@ -1630,7 +1631,7 @@ 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;
@@ -1661,7 +1662,7 @@ 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;
     }
@@ -1686,7 +1687,8 @@ 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)
 {
@@ -1695,7 +1697,7 @@ 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));
 }
 
@@ -1706,19 +1708,24 @@ 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,
+			     state,
 			     prt->connected,
 			     NULL,
 			     0,
@@ -1747,6 +1754,7 @@ 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;
@@ -1762,12 +1770,13 @@ deliver_vec_message(Port* prt,			/* Port */
     if (!rp)
 	return;
 
+    state = erts_smp_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;
@@ -1778,7 +1787,7 @@ 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--;
@@ -1864,7 +1873,7 @@ 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 
@@ -1899,7 +1908,8 @@ static void flush_port(Port *p)
 	ASSERT(!p->xports);
 #endif
     }
-    if ((p->status & ERTS_PORT_SFLGS_DEAD) == 0 && is_port_ioq_empty(p)) {
+    if ((erts_smp_atomic32_read_nob(&p->state) & ERTS_PORT_SFLGS_DEAD) == 0
+	&& is_port_ioq_empty(p)) {
 	terminate_port(p);
     }
 }
@@ -1911,7 +1921,7 @@ 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));
@@ -1919,10 +1929,10 @@ terminate_port(Port *prt)
     ASSERT(!prt->nlinks);
     ASSERT(!prt->monitors);
 
-    /* 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);
+    /* state may be altered by kill_port() below */
+    state = erts_smp_atomic32_read_band_nob(&prt->state,
+					    ~ERTS_PORT_SFLG_SEND_CLOSED);
+    if (state & ERTS_PORT_SFLG_SEND_CLOSED) {
 	send_closed_port_id = prt->id;
 	connected_id = prt->connected;
     }
@@ -1978,7 +1988,8 @@ terminate_port(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)) {
+    if ((state & ERTS_PORT_SFLG_HALT)
+	&& (erts_smp_atomic32_dec_read_nob(&erts_halt_progress) == 0)) {
 	erts_smp_port_unlock(prt); /* We will exit and never return */
 	erl_exit_flush_async(erts_halt_code, "");
     }
@@ -2100,6 +2111,7 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason)
 {
    ErtsLink *lnk;
    Eterm rreason;
+   erts_aint32_t state;
 
    ERTS_SMP_CHK_NO_PROC_LOCKS;
    ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p));
@@ -2119,9 +2131,10 @@ 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))
+   state = erts_smp_atomic32_read_nob(&p->state);
+   if ((state & (ERTS_PORT_SFLGS_DEAD
+		 | ERTS_PORT_SFLG_EXITING
+		 | ERTS_PORT_SFLG_IMMORTAL))
        || ((reason == am_normal) &&
 	   ((from != p->connected) && (from != p->id)))) {
       return;
@@ -2142,7 +2155,7 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason)
    if (p->reg != NULL)
        (void) erts_unregister_name(NULL, 0, p, p->reg->name);
 
-   erts_port_status_bor_set(p, ERTS_PORT_SFLG_EXITING);
+   state = erts_smp_atomic32_read_bor_relb(&p->state, ERTS_PORT_SFLG_EXITING);
 
    {
        SweepContext sc = {p->id, rreason};
@@ -2158,17 +2171,20 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason)
    } 
    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_smp_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_smp_atomic32_read_bset_relb(&p->state,
+					(ERTS_PORT_SFLG_EXITING
+					 | ERTS_PORT_SFLG_CLOSING),
+					ERTS_PORT_SFLG_CLOSING);
       flush_port(p);
    }
    else {
@@ -2217,7 +2233,8 @@ void erts_port_command(Process *proc,
 	if ((pid = port->connected) == tp[1]) {
 	    /* PID must be connected */
 	    if (tp[2] == am_close) {
-		erts_port_status_bor_set(port, ERTS_PORT_SFLG_SEND_CLOSED);
+		erts_smp_atomic32_read_bor_relb(&port->state,
+						ERTS_PORT_SFLG_SEND_CLOSED);
 		erts_do_exit_port(port, pid, am_normal);
 
 #ifdef USE_VM_PROBES
@@ -2443,13 +2460,14 @@ void
 print_port_info(int to, void *arg, int i)
 {
     Port* p = &erts_port[i];
+    erts_aint32_t state = erts_smp_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) {
+    if (state & ERTS_PORT_SFLG_CONNECTED) {
 	erts_print(to, arg, "Connected: %T", p->connected);
 	erts_print(to, arg, "\n");
     }
@@ -2497,8 +2515,8 @@ set_busy_port(ErlDrvPort port_num, int on)
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(&erts_port[port_num]));
 
     if (on) {
-        erts_port_status_bor_set(&erts_port[port_num],
-				 ERTS_PORT_SFLG_PORT_BUSY);
+	erts_smp_atomic32_read_bor_relb(&erts_port[port_num].state,
+					ERTS_PORT_SFLG_PORT_BUSY);
 #ifdef USE_VM_PROBES
         if (DTRACE_ENABLED(port_busy)) {
             erts_snprintf(port_str, sizeof(port_str),
@@ -2508,8 +2526,8 @@ set_busy_port(ErlDrvPort port_num, int on)
 #endif
     } else {
         ErtsProcList* plp = erts_port[port_num].suspended;
-        erts_port_status_band_set(&erts_port[port_num],
-				  ~ERTS_PORT_SFLG_PORT_BUSY);
+	erts_smp_atomic32_read_band_relb(&erts_port[port_num].state,
+					 ~ERTS_PORT_SFLG_PORT_BUSY);
         erts_port[port_num].suspended = NULL;
 
 #ifdef USE_VM_PROBES
@@ -2576,19 +2594,27 @@ void set_port_control_flags(ErlDrvPort port_num, int flags)
     erts_port[port_num].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;
@@ -2624,8 +2650,9 @@ int async_ready(Port *p, void* data)
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
     if (p) {
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&p->state);
 	ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(p));
-	ASSERT(!(p->status & ERTS_PORT_SFLGS_DEAD));
+	ASSERT(!(state & ERTS_PORT_SFLGS_DEAD));
 	if (p->drv_ptr->ready_async != NULL) {
 #ifdef USE_VM_PROBES
             if (DTRACE_ENABLED(driver_ready_async)) {
@@ -2641,7 +2668,7 @@ int async_ready(Port *p, void* data)
 	    ASSERT(!p->xports);
 #endif
 	}
-	if ((p->status & ERTS_PORT_SFLG_CLOSING) && is_port_ioq_empty(p)) {
+	if ((state & ERTS_PORT_SFLG_CLOSING) && is_port_ioq_empty(p)) {
 	    terminate_port(p);
 	}
     }
@@ -2736,7 +2763,7 @@ 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);
+	    erts_smp_port_minor_lock(prt);
 	    if (id != prt->id) {
 		len = nlen = 0;
 		name = driver_name = NULL;
@@ -2764,7 +2791,7 @@ erts_get_port_names(Eterm id)
 		}
 		do_realloc = 0;
 	    }
-	    erts_smp_port_state_unlock(prt);
+	    erts_smp_port_minor_unlock(prt);
 	} while (do_realloc);
     }
     return pnp;
@@ -2803,7 +2830,7 @@ ErlDrvTermData driver_mk_term_nil(void)
 
 void driver_report_exit(int ix, int status)
 {
-   Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
    Eterm* hp;
    Eterm tuple;
    Process *rp;
@@ -2852,14 +2879,13 @@ deliver_term_check_port(ErlDrvPort drvport)
 	res = -1; /* invalid */
     else {
 	Port* prt = &erts_port[ix];
-	erts_smp_port_state_lock(prt);
-	if (!(prt->status & ERTS_PORT_SFLGS_INVALID_LOOKUP))
+	erts_aint32_t state = erts_smp_atomic32_read_nob(&prt->state);
+	if (!(state & ERTS_PORT_SFLGS_INVALID_LOOKUP))
 	    res = 1; /* ok */
-	else if (prt->status & ERTS_PORT_SFLG_CLOSING)
+	else if (state & ERTS_PORT_SFLG_CLOSING)
 	    res = 0; /* closing */
 	else
 	    res = -1; /* invalid (dead) */
-	erts_smp_port_state_unlock(prt);
     }
     return res;
 }
@@ -3428,7 +3454,7 @@ driver_deliver_term(ErlDrvPort port,
 int 
 driver_output_term(ErlDrvPort ix, ErlDrvTermData* data, int len)
 {
-    Port* prt = erts_drvport2port(ix);
+    Port* prt = erts_drvport2port(ix, NULL);
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
@@ -3454,19 +3480,20 @@ 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,
@@ -3488,7 +3515,8 @@ 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;
 
@@ -3497,12 +3525,12 @@ 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,
@@ -3514,10 +3542,10 @@ 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, prt->connected, hbuf, hlen, buf, len);
     else
-	deliver_read_message(prt, prt->connected, hbuf, hlen, buf, len, 0);
+	deliver_read_message(prt, state, prt->connected, hbuf, hlen, buf, len, 0);
     return 0;
 }
 
@@ -3538,6 +3566,7 @@ 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;
 
@@ -3550,13 +3579,13 @@ 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 ! */
@@ -3826,7 +3855,7 @@ 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,
@@ -4283,7 +4312,7 @@ drv_cancel_timer(Port *prt)
 
 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;
 
@@ -4310,7 +4339,7 @@ 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));
@@ -4322,7 +4351,7 @@ 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;
 
@@ -4400,8 +4429,10 @@ int driver_monitor_process(ErlDrvPort port,
 {
     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();
+#endif
     int ix = (int) port;
     if (ix < 0 || erts_max_ports <= ix) {
 	return -1;
@@ -4410,15 +4441,9 @@ int driver_monitor_process(ErlDrvPort port,
 
     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_smp_atomic32_read_nob(&erts_port[ix].state);
 
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return -1;
     }
@@ -4488,8 +4513,10 @@ int driver_demonitor_process(ErlDrvPort port,
 {
     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();
+#endif
     int ix = (int) port;
     if (ix < 0 || erts_max_ports <= ix) {
 	return -1;
@@ -4498,15 +4525,9 @@ int driver_demonitor_process(ErlDrvPort port,
 
     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_smp_atomic32_read_nob(&erts_port[ix].state);
 
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return -1;
     }
@@ -4558,8 +4579,10 @@ ErlDrvTermData driver_get_monitored_process(ErlDrvPort port,
 {
     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();
+#endif
     int ix = (int) port;
     if (ix < 0 || erts_max_ports <= ix) {
 	return driver_term_nil;
@@ -4568,15 +4591,8 @@ ErlDrvTermData driver_get_monitored_process(ErlDrvPort port,
 
     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);
-    }
-
-    if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
+    state = erts_smp_atomic32_read_nob(&erts_port[ix].state);
+    if (state & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) {
 	DRV_MONITOR_UNLOCK_PDL(prt);
 	return driver_term_nil;
     }
@@ -4651,7 +4667,8 @@ 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;
 
@@ -4659,10 +4676,10 @@ 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)) {
+    } else if (eof && (state & ERTS_PORT_SFLG_SOFT_EOF)) {
 	deliver_result(prt->id, prt->connected, am_eof);
     } else {
 	/* XXX UGLY WORK AROUND, Let do_exit_port terminate the port */
@@ -4684,7 +4701,7 @@ 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;
 
@@ -4757,14 +4774,14 @@ 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;
 }
 
 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;
@@ -4774,7 +4791,7 @@ ErlDrvTermData driver_connected(ErlDrvPort ix)
 
 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;
@@ -4784,7 +4801,7 @@ 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;