Merge branch 'fix/waitqueue-barriers' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index dd644d7..cc1cc35 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -344,6 +344,9 @@ loop_lock:
                pending = pending->bi_next;
                cur->bi_next = NULL;
 
+               /*
+                * atomic_dec_return implies a barrier for waitqueue_active
+                */
                if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
                    waitqueue_active(&fs_info->async_submit_wait))
                        wake_up(&fs_info->async_submit_wait);