Merge branch 'lh/demonitor-flush/OTP-11039' into maint

* lh/demonitor-flush/OTP-11039:
  Use erlang:demonitor(Ref, [flush]) where applicable

4 files changed, 8 insertions, 28 deletions

diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 45aef0ea80..50812cc532 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -1246,13 +1246,8 @@ req(Proc, R) ->
 	{'DOWN', Ref, process, Proc, _Info} ->
             badarg;
 	{Proc, Reply} ->
-	    erlang:demonitor(Ref),
-	    receive 
-		{'DOWN', Ref, process, Proc, _Reason} ->
-                    Reply
-	    after 0 ->
-                    Reply
-	    end
+	    erlang:demonitor(Ref, [flush]),
+	    Reply
     end.
 
 %% Inlined.
diff --git a/lib/stdlib/src/epp.erl b/lib/stdlib/src/epp.erl
index 0a1caa7178..e31cd63f69 100644
--- a/lib/stdlib/src/epp.erl
+++ b/lib/stdlib/src/epp.erl
@@ -1339,8 +1339,7 @@ epp_reply(From, Rep) ->
 wait_epp_reply(Epp, Mref) ->
     receive
 	{epp_reply,Epp,Rep} ->
-	    erlang:demonitor(Mref),
-	    receive {'DOWN',Mref,_,_,_} -> ok after 0 -> ok end,
+	    erlang:demonitor(Mref, [flush]),
 	    Rep;
 	{'DOWN',Mref,_,_,E} ->
 	    receive {epp_reply,Epp,Rep} -> Rep
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index 9c4b95acf6..30a81ade49 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -472,11 +472,11 @@ rec_nodes(Tag, [{N,R}|Tail], Name, Badnodes, Replies, Time, TimerId ) ->
 	{'DOWN', R, _, _, _} ->
 	    rec_nodes(Tag, Tail, Name, [N|Badnodes], Replies, Time, TimerId);
 	{{Tag, N}, Reply} ->  %% Tag is bound !!!
-	    unmonitor(R), 
+	    erlang:demonitor(R, [flush]),
 	    rec_nodes(Tag, Tail, Name, Badnodes, 
 		      [{N,Reply}|Replies], Time, TimerId);
 	{timeout, TimerId, _} ->	
-	    unmonitor(R),
+	    erlang:demonitor(R, [flush]),
 	    %% Collect all replies that already have arrived
 	    rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies)
     end;
@@ -527,10 +527,10 @@ rec_nodes_rest(Tag, [{N,R}|Tail], Name, Badnodes, Replies) ->
 	{'DOWN', R, _, _, _} ->
 	    rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies);
 	{{Tag, N}, Reply} -> %% Tag is bound !!!
-	    unmonitor(R),
+	    erlang:demonitor(R, [flush]),
 	    rec_nodes_rest(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies])
     after 0 ->
-	    unmonitor(R),
+	    erlang:demonitor(R, [flush]),
 	    rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies)
     end;
 rec_nodes_rest(Tag, [N|Tail], Name, Badnodes, Replies) ->
@@ -572,16 +572,6 @@ start_monitor(Node, Name) when is_atom(Node), is_atom(Name) ->
 	    end
     end.
 
-%% Cancels a monitor started with Ref=erlang:monitor(_, _).
-unmonitor(Ref) when is_reference(Ref) ->
-    erlang:demonitor(Ref),
-    receive
-	{'DOWN', Ref, _, _, _} ->
-	    true
-    after 0 ->
-	    true
-    end.
-
 %%% ---------------------------------------------------
 %%% Message handling functions
 %%% ---------------------------------------------------
diff --git a/lib/stdlib/src/io.erl b/lib/stdlib/src/io.erl
index c92e9e3ade..53728237ca 100644
--- a/lib/stdlib/src/io.erl
+++ b/lib/stdlib/src/io.erl
@@ -598,11 +598,7 @@ default_output() ->
 wait_io_mon_reply(From, Mref) ->
     receive
 	{io_reply, From, Reply} ->
-	    erlang:demonitor(Mref),
-	    receive 
-		{'DOWN', Mref, _, _, _} -> true
-	    after 0 -> true
-	    end,
+	    erlang:demonitor(Mref, [flush]),
 	    Reply;
 	{'EXIT', From, _What} ->
 	    receive