[PATCH] writeback: update stale account_page_redirty() comment

[Greg Thelen <gthelen@google.com>]

commit 93f78d882865 ("writeback: move backing_dev_info->bdi_stat[] into
bdi_writeback") replaced BDI_DIRTIED with WB_DIRTIED in
account_page_redirty().  Update comment to track that change.
  BDI_DIRTIED => WB_DIRTIED
  BDI_WRITTEN => WB_WRITTEN

Signed-off-by: Greg Thelen <gthelen@google.com>
---
 mm/page-writeback.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 337c6afb3345..6551d3b0dc30 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2490,8 +2490,8 @@ EXPORT_SYMBOL(__set_page_dirty_nobuffers);
 
 /*
  * Call this whenever redirtying a page, to de-account the dirty counters
- * (NR_DIRTIED, BDI_DIRTIED, tsk->nr_dirtied), so that they match the written
- * counters (NR_WRITTEN, BDI_WRITTEN) in long term. The mismatches will lead to
+ * (NR_DIRTIED, WB_DIRTIED, tsk->nr_dirtied), so that they match the written
+ * counters (NR_WRITTEN, WB_WRITTEN) in long term. The mismatches will lead to
  * systematic errors in balanced_dirty_ratelimit and the dirty pages position
  * control.
  */
-- 
2.18.0.rc2.346.g013aa6912e-goog