[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>

1 files changed, 5 insertions, 8 deletions

diff --git a/fs/exec.c b/fs/exec.c
index fc02dadc604a..6d9521636aaa 100644
--- 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);
 }