svn commit: r293608 - stable/10/sys/compat/linux

[Dmitry Chagin]

Author: dchagin
Date: Sat Jan  9 18:28:15 2016
New Revision: 293608
URL: https://svnweb.freebsd.org/changeset/base/293608

Log:
  MFC r288994 (by bdrewery):
  
  Remove redundant RFFPWAIT/vfork(2) handling in Linux fork(2) and clone(2) wrappers.
  
  r161611 added some of the code from sys_vfork() directly into the Linux
  module wrappers since they use RFSTOPPED.  In r232240, the RFFPWAIT handling
  was moved to syscallret(), thus this code in the Linux module is no longer
  needed as it will be called later.
  
  This also allows the Linux wrappers to benefit from the fix in r275616 for
  threads not getting suspended if their vforked child is stopped while they
  wait on them.

Modified:
  stable/10/sys/compat/linux/linux_fork.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/compat/linux/linux_fork.c
==============================================================================
--- stable/10/sys/compat/linux/linux_fork.c	Sat Jan  9 18:24:53 2016	(r293607)
+++ stable/10/sys/compat/linux/linux_fork.c	Sat Jan  9 18:28:15 2016	(r293608)
@@ -107,20 +107,14 @@ linux_vfork(struct thread *td, struct li
 		printf(ARGS(vfork, ""));
 #endif
 
-	/* Exclude RFPPWAIT */
-	if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2,
-	    NULL, 0)) != 0)
+	if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED,
+	    0, &p2, NULL, 0)) != 0)
 		return (error);
 
-
 	td2 = FIRST_THREAD_IN_PROC(p2);
 
 	linux_proc_init(td, td2, 0);
 
-	PROC_LOCK(p2);
-	p2->p_flag |= P_PPWAIT;
-	PROC_UNLOCK(p2);
-
    	td->td_retval[0] = p2->p_pid;
 
 	/*
@@ -131,12 +125,6 @@ linux_vfork(struct thread *td, struct li
 	sched_add(td2, SRQ_BORING);
 	thread_unlock(td2);
 
-	/* wait for the children to exit, ie. emulate vfork */
-	PROC_LOCK(p2);
-	while (p2->p_flag & P_PPWAIT)
-		cv_wait(&p2->p_pwait, &p2->p_mtx);
-	PROC_UNLOCK(p2);
-
 	return (0);
 }
 
@@ -180,6 +168,9 @@ linux_clone_proc(struct thread *td, stru
 		if (args->parent_tidptr == NULL)
 			return (EINVAL);
 
+	if (args->flags & LINUX_CLONE_VFORK)
+		ff |= RFPPWAIT;
+
 	error = fork1(td, ff, 0, &p2, NULL, 0);
 	if (error)
 		return (error);
@@ -229,12 +220,6 @@ linux_clone_proc(struct thread *td, stru
 		    exit_signal);
 #endif
 
-	if (args->flags & LINUX_CLONE_VFORK) {
-	   	PROC_LOCK(p2);
-	   	p2->p_flag |= P_PPWAIT;
-	   	PROC_UNLOCK(p2);
-	}
-
 	/*
 	 * Make this runnable after we are finished with it.
 	 */
@@ -245,14 +230,6 @@ linux_clone_proc(struct thread *td, stru
 
 	td->td_retval[0] = p2->p_pid;
 
-	if (args->flags & LINUX_CLONE_VFORK) {
-		/* wait for the children to exit, ie. emulate vfork */
-		PROC_LOCK(p2);
-		while (p2->p_flag & P_PPWAIT)
-			cv_wait(&p2->p_pwait, &p2->p_mtx);
-		PROC_UNLOCK(p2);
-	}
-
 	return (0);
 }