[PATCH] writeback: use rb_entry()

[Geliang Tang]

To make the code clearer, use rb_entry() instead of container_of() to
deal with rbtree.

Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>
---
 mm/backing-dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 3bfed5ab..ffb77a1 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -410,8 +410,8 @@ wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
 
 	while (*node != NULL) {
 		parent = *node;
-		congested = container_of(parent, struct bdi_writeback_congested,
-					 rb_node);
+		congested = rb_entry(parent, struct bdi_writeback_congested,
+				     rb_node);
 		if (congested->blkcg_id < blkcg_id)
 			node = &parent->rb_left;
 		else if (congested->blkcg_id > blkcg_id)
-- 
2.9.3