Merge branch 'fix/waitqueue-barriers' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.4

2015-10-12 16:24:40 -07:00
parent 62fb50ab7c ee86395458
commit 6db4a7335d
12 changed files with 62 additions and 7 deletions
--- 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);