1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index d800d5142184..1d0f7a2ff73b 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -38,6 +38,12 @@ struct elevator_ops
         elevator_merged_fn *elevator_merged_fn;
         elevator_merge_req_fn *elevator_merge_req_fn;
         elevator_allow_merge_fn *elevator_allow_merge_fn;
+
+        /*
+         * Used for both plugged list and elevator merging and in the
+         * former case called without queue_lock.  Read comment on top of
+         * attempt_plug_merge() for details.
+         */
         elevator_bio_merged_fn *elevator_bio_merged_fn;
 
         elevator_dispatch_fn *elevator_dispatch_fn;