[PATCH] coredump_wait() cleanup

This patch deletes pointless code from coredump_wait().

1. It does useless mm->core_waiters inc/dec under mm->mmap_sem,
   but any changes to ->core_waiters have no effect until we drop
   ->mmap_sem.

2. It calls yield() for absolutely unknown reason.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/exec.c b/fs/exec.c
index fc02dad..6d95216 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1417,19 +1417,16 @@ static void zap_threads (struct mm_struct *mm)
 static void coredump_wait(struct mm_struct *mm)
 {
        DECLARE_COMPLETION(startup_done);
+       int core_waiters;
 
-       mm->core_waiters++; /* let other threads block */
        mm->core_startup_done = &startup_done;
 
-       /* give other threads a chance to run: */
-       yield();
-
        zap_threads(mm);
-       if (--mm->core_waiters) {
-               up_write(&mm->mmap_sem);
+       core_waiters = mm->core_waiters;
+       up_write(&mm->mmap_sem);
+
+       if (core_waiters)
                wait_for_completion(&startup_done);
-       } else
-               up_write(&mm->mmap_sem);
        BUG_ON(mm->core_waiters);
 }