[PATCH] Add smp_mb__after_clear_bit() to unlock_kiocb()
Add smp_mb__after_clear_bit() to unlock_kiocb()
AIO's use of wait_on_bit_lock()/wake_up_bit() forgot to add a barrier
between clearing its lock bit and calling wake_up_bit() so wake_up_bit()'s
unlocked waitqueue_active() can race. This puts AIO's use in line with the
others and the comment above wake_up_bit().
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Acked-by: Benjamin LaHaise <bcrl@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/aio.c b/fs/aio.c
index 38f6268..0e11e31 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -562,6 +562,7 @@
static inline void unlock_kiocb(struct kiocb *iocb)
{
kiocbClearLocked(iocb);
+ smp_mb__after_clear_bit();
wake_up_bit(&iocb->ki_flags, KIF_LOCKED);
}