From: Huaisheng Ye Date: Fri, 12 Apr 2019 15:28:14 +0000 (-0400) Subject: dm writecache: add unlikely for returned value of rb_next/prev X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=84420b1e5d7254e58f551e32244d13c8e124bdcc;p=linux.git dm writecache: add unlikely for returned value of rb_next/prev In functions writecache_discard() and writecache_find_entry() there is a high probablity that the pointer of structure rb_node won't equal NULL. Add unlikely for the pointer node NULL. Signed-off-by: Huaisheng Ye Signed-off-by: Mike Snitzer --- diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index 5b4d1c11eff14..cfbbfbc028f97 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -571,7 +571,7 @@ static struct wc_entry *writecache_find_entry(struct dm_writecache *wc, node = rb_prev(&e->rb_node); else node = rb_next(&e->rb_node); - if (!node) + if (unlikely(!node)) return e; e2 = container_of(node, struct wc_entry, rb_node); if (read_original_sector(wc, e2) != block) @@ -804,7 +804,7 @@ static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_ writecache_free_entry(wc, e); } - if (!node) + if (unlikely(!node)) break; e = container_of(node, struct wc_entry, rb_node);