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.

Reviewed by:	jhb, kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D3828

1 files changed, 5 insertions, 28 deletions

diff --git a/sys/compat/linux/linux_fork.c b/sys/compat/linux/linux_fork.c
index dd3b894..d0f73ad 100644
--- a/sys/compat/linux/linux_fork.c
+++ b/sys/compat/linux/linux_fork.c
@@ -106,20 +106,14 @@ linux_vfork(struct thread *td, struct linux_vfork_args *args)
 		printf(ARGS(vfork, ""));
 #endif
 
-	/* Exclude RFPPWAIT */
-	if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2,
-	    NULL, 0, NULL)) != 0)
+	if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED,
+	    0, &p2, NULL, 0, NULL)) != 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;
 
 	/*
@@ -130,12 +124,6 @@ linux_vfork(struct thread *td, struct linux_vfork_args *args)
 	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);
 }
 
@@ -179,6 +167,9 @@ linux_clone_proc(struct thread *td, struct linux_clone_args *args)
 		if (args->parent_tidptr == NULL)
 			return (EINVAL);
 
+	if (args->flags & LINUX_CLONE_VFORK)
+		ff |= RFPPWAIT;
+
 	error = fork1(td, ff, 0, &p2, NULL, 0, NULL);
 	if (error)
 		return (error);
@@ -228,12 +219,6 @@ linux_clone_proc(struct thread *td, struct linux_clone_args *args)
 		    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.
 	 */
@@ -244,14 +229,6 @@ linux_clone_proc(struct thread *td, struct linux_clone_args *args)
 
 	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);
 }