block: correct the blk drain name comment

[Weng Meiling <wengmeiling.weng@huawei.com>]

After patch commit 807592a4fafb("block: Let blk_drain_queue() caller
obtain the queue lock") the function blk_drain_queue() had been renamed
to __blk_drain_queue(), so correct the related comments.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
---
 block/blk-cgroup.c     | 2 +-
 block/blk-core.c       | 2 +-
 include/linux/blkdev.h | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e4a4145..8234eb1 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -856,7 +856,7 @@ int blkcg_init_queue(struct request_queue *q)
  * blkcg_drain_queue - drain blkcg part of request_queue
  * @q: request_queue to drain
  *
- * Called from blk_drain_queue().  Responsible for draining blkcg part.
+ * Called from __blk_drain_queue().  Responsible for draining blkcg part.
  */
 void blkcg_drain_queue(struct request_queue *q)
 {
diff --git a/block/blk-core.c b/block/blk-core.c
index a0e3096..f62d8a0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -279,7 +279,7 @@ inline void __blk_run_queue_uncond(struct request_queue *q)
 	 * Some request_fn implementations, e.g. scsi_request_fn(), unlock
 	 * the queue lock internally. As a result multiple threads may be
 	 * running such a request function concurrently. Keep track of the
-	 * number of active request_fn invocations such that blk_drain_queue()
+	 * number of active request_fn invocations such that __blk_drain_queue()
 	 * can wait until all these request_fn calls have finished.
 	 */
 	q->request_fn_active++;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0d84981..4835cc9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -421,7 +421,7 @@ struct request_queue {
 	unsigned int		nr_sorted;
 	unsigned int		in_flight[2];
 	/*
-	 * Number of active block driver functions for which blk_drain_queue()
+	 * Number of active block driver functions for which __blk_drain_queue()
 	 * must wait. Must be incremented around functions that unlock the
 	 * queue_lock internally, e.g. scsi_request_fn().
 	 */
-- 
1.8.3