diff mbox series

[V5,1/4] block: use test_and_{clear|test}_bit to set/clear QUEUE_FLAG_QUIESCED

Message ID 20200911024117.62480-2-ming.lei@redhat.com (mailing list archive)
State New, archived
Headers show
Series blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING | expand

Commit Message

Ming Lei Sept. 11, 2020, 2:41 a.m. UTC 
Prepare for replacing srcu with percpu-refcount for implementing queue
quiesce.

The following patch needs to avoid duplicated quiesce action for
BLK_MQ_F_BLOCKING, so use test_and_{clear|test}_bit to set/clear
QUEUE_FLAG_QUIESCED.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Cc: Chao Leng <lengchao@huawei.com>
---
 block/blk-core.c | 13 +++++++++++++
 block/blk-mq.c   | 11 ++++++++---
 block/blk.h      |  2 ++
 3 files changed, 23 insertions(+), 3 deletions(-)

Comments

Hannes Reinecke Sept. 11, 2020, 6:03 a.m. UTC | #1 
On 9/11/20 4:41 AM, Ming Lei wrote:
> Prepare for replacing srcu with percpu-refcount for implementing queue
> quiesce.
> 
> The following patch needs to avoid duplicated quiesce action for
> BLK_MQ_F_BLOCKING, so use test_and_{clear|test}_bit to set/clear
> QUEUE_FLAG_QUIESCED.
> 
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> Cc: Bart Van Assche <bvanassche@acm.org>
> Cc: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
> Cc: Chao Leng <lengchao@huawei.com>
> ---
>   block/blk-core.c | 13 +++++++++++++
>   block/blk-mq.c   | 11 ++++++++---
>   block/blk.h      |  2 ++
>   3 files changed, 23 insertions(+), 3 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
diff mbox series

Patch

diff --git a/block/blk-core.c b/block/blk-core.c
index 093649bd252e..de440733609c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -107,6 +107,19 @@  bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
 
+/**
+ * blk_queue_flag_test_and_clear - atomically test and clear a queue flag
+ * @flag: flag to be clear
+ * @q: request queue
+ *
+ * Returns the previous value of @flag - 0 if the flag was not set and 1 if
+ * the flag was set.
+ */
+bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q)
+{
+	return test_and_clear_bit(flag, &q->queue_flags);
+}
+
 void blk_rq_init(struct request_queue *q, struct request *rq)
 {
 	memset(rq, 0, sizeof(*rq));
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4abb71459f94..efd17a80fcdf 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -199,13 +199,18 @@  void blk_mq_unfreeze_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
 
+static bool __blk_mq_quiesce_queue_nowait(struct request_queue *q)
+{
+	return blk_queue_flag_test_and_set(QUEUE_FLAG_QUIESCED, q);
+}
+
 /*
  * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
  * mpt3sas driver such that this function can be removed.
  */
 void blk_mq_quiesce_queue_nowait(struct request_queue *q)
 {
-	blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
+	__blk_mq_quiesce_queue_nowait(q);
 }
 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
 
@@ -224,7 +229,7 @@  void blk_mq_quiesce_queue(struct request_queue *q)
 	unsigned int i;
 	bool rcu = false;
 
-	blk_mq_quiesce_queue_nowait(q);
+	__blk_mq_quiesce_queue_nowait(q);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (hctx->flags & BLK_MQ_F_BLOCKING)
@@ -246,7 +251,7 @@  EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
  */
 void blk_mq_unquiesce_queue(struct request_queue *q)
 {
-	blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
+	blk_queue_flag_test_and_clear(QUEUE_FLAG_QUIESCED, q);
 
 	/* dispatch requests which are inserted during quiescing */
 	blk_mq_run_hw_queues(q, true);
diff --git a/block/blk.h b/block/blk.h
index c08762e10b04..312a060ea2a2 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -448,4 +448,6 @@  int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		struct page *page, unsigned int len, unsigned int offset,
 		unsigned int max_sectors, bool *same_page);
 
+bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q);
+
 #endif /* BLK_INTERNAL_H */