[v2,1/8] blk-mq: introduce blk_mq_unquiesce_queue

Commit Message

Ming Lei May 27, 2017, 2:21 p.m. UTC

We use blk_mq_start_stopped_hw_queues() implictely
as pair of blk_mq_quiesce_queue() for unquiescing the queue,
so we introduce blk_mq_unquiesce_queue() and make it
as pair of blk_mq_quiesce_queue() explicitely.

This function is for fixing current quiescing mechanism
in the following patches.

Signed-off-by: Ming Lei <[e-mail]>
---
 block/blk-mq.c         | 13 +++++++++++++
 include/linux/blkdev.h |  1 +
 2 files changed, 14 insertions(+)

Comments

Bart Van Assche May 30, 2017, 3:09 p.m. UTC | #1

On Sat, 2017-05-27 at 22:21 +0800, Ming Lei wrote:
> + * blk_mq_unquiesce_queue() - pair of blk_mq_quiesce_queue()
                                 ^^^^ 

Sorry but that comment is incomprehensible to me. Did you perhaps mean
"counterpart" instead of "pair"?

Bart.

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f2224ffd225d..8ecbbb718946 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -181,6 +181,19 @@  void blk_mq_quiesce_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
 
+/*
+ * blk_mq_unquiesce_queue() - pair of blk_mq_quiesce_queue()
+ * @q: request queue.
+ *
+ * This function recovers queue into the state before quiescing
+ * which is done by blk_mq_quiesce_queue.
+ */
+void blk_mq_unquiesce_queue(struct request_queue *q)
+{
+	blk_mq_start_stopped_hw_queues(q, true);
+}
+EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
+
 void blk_mq_wake_waiters(struct request_queue *q)
 {
 	struct blk_mq_hw_ctx *hctx;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ab92c4ea138b..41291be82ac4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -964,6 +964,7 @@  extern void __blk_run_queue_uncond(struct request_queue *q);
 extern void blk_run_queue(struct request_queue *);
 extern void blk_run_queue_async(struct request_queue *q);
 extern void blk_mq_quiesce_queue(struct request_queue *q);
+extern void blk_mq_unquiesce_queue(struct request_queue *q);
 extern int blk_rq_map_user(struct request_queue *, struct request *,
 			   struct rq_map_data *, void __user *, unsigned long,
 			   gfp_t);