From a83342aa0c8f0ca90057d3837ae8d198186e5153 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 16 Feb 2015 19:36:47 +0100 Subject: btrfs: add comments to barriers before waitqueue_active Reduce number of undocumented barriers out there. Signed-off-by: David Sterba --- fs/btrfs/compression.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/btrfs/compression.c') diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 57ee8ca29b06..3a9317ce67f8 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -839,6 +839,9 @@ static void free_workspace(int type, struct list_head *workspace) btrfs_compress_op[idx]->free_workspace(workspace); atomic_dec(alloc_workspace); wake: + /* + * Make sure counter is updated before we wake up waiters. + */ smp_mb(); if (waitqueue_active(workspace_wait)) wake_up(workspace_wait); -- cgit v1.2.3