[2/3] blk-mq: Provide freeze queue timeout

Commit Message

Keith Busch March 1, 2017, 7:22 p.m. UTC

A driver may wish to take corrective action if queued requests do not
complete within a set time.

Signed-off-by: Keith Busch <[e-mail]>
---
 block/blk-mq.c         | 9 +++++++++
 include/linux/blk-mq.h | 2 ++
 2 files changed, 11 insertions(+)

Comments

Christoph Hellwig March 2, 2017, 12:14 a.m. UTC | #1

> +int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
> +				     unsigned long timeout)
> +{
> +	return wait_event_timeout(q->mq_freeze_wq,
> +					percpu_ref_is_zero(&q->q_usage_counter),
> +					timeout);
> +}
> +EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);

Can you just add the timeout argument to blk_mq_freeze_queue_wait?
Existing callers can pass 0, which is interpreted as no timeout by
the low-level wait code.

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8da2c04..a5e66a7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -81,6 +81,15 @@  void blk_mq_freeze_queue_wait(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
 
+int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
+				     unsigned long timeout)
+{
+	return wait_event_timeout(q->mq_freeze_wq,
+					percpu_ref_is_zero(&q->q_usage_counter),
+					timeout);
+}
+EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
+
 /*
  * Guarantee no request is in use, so we can change any data structure of
  * the queue afterward.
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 8dacf68..b296a90 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -246,6 +246,8 @@  void blk_mq_freeze_queue(struct request_queue *q);
 void blk_mq_unfreeze_queue(struct request_queue *q);
 void blk_mq_freeze_queue_start(struct request_queue *q);
 void blk_mq_freeze_queue_wait(struct request_queue *q);
+int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
+				     unsigned long timeout);
 int blk_mq_reinit_tagset(struct blk_mq_tag_set *set);
 
 int blk_mq_map_queues(struct blk_mq_tag_set *set);