[v3,02/11] blk-mq: Introduce blk_mq_hctx_stopped()

Commit Message

Bart Van Assche Oct. 18, 2016, 9:49 p.m. UTC

Multiple functions test the BLK_MQ_S_STOPPED bit so introduce
a helper function that performs this test.

Signed-off-by: Bart Van Assche <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Hannes Reinecke <[e-mail]>
Cc: Sagi Grimberg <[e-mail]>
Cc: Johannes Thumshirn <[e-mail]>
---
 block/blk-mq.c         | 12 ++++++------
 drivers/md/dm-rq.c     |  2 +-
 include/linux/blk-mq.h |  5 +++++
 3 files changed, 12 insertions(+), 7 deletions(-)

Comments

Christoph Hellwig Oct. 19, 2016, 1:19 p.m. UTC | #1

On Tue, Oct 18, 2016 at 02:49:09PM -0700, Bart Van Assche wrote:
> Multiple functions test the BLK_MQ_S_STOPPED bit so introduce
> a helper function that performs this test.

Looks sensible.  Any reason to have it in the public blk-mq.h instead
of the private one, though?  I see that dm is using it with this patch,
but that usage should go away once your full series is merged, right?
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Bart Van Assche Oct. 19, 2016, 3:58 p.m. UTC | #2

On 10/19/2016 06:19 AM, Christoph Hellwig wrote:
> On Tue, Oct 18, 2016 at 02:49:09PM -0700, Bart Van Assche wrote:
>> Multiple functions test the BLK_MQ_S_STOPPED bit so introduce
>> a helper function that performs this test.
>
> Looks sensible.  Any reason to have it in the public blk-mq.h instead
> of the private one, though?  I see that dm is using it with this patch,
> but that usage should go away once your full series is merged, right?

Hello Christoph,

Moving the blk_mq_hctx_stopped() declaration from the public to the 
private blk-mq.h header file should be possible. I will look into this.

Bart.
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Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index b5dcafb..b52b3a6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -787,7 +787,7 @@  static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
 	struct list_head *dptr;
 	int queued;
 
-	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
+	if (unlikely(blk_mq_hctx_stopped(hctx)))
 		return;
 
 	WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
@@ -912,8 +912,8 @@  static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
 
 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
 {
-	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state) ||
-	    !blk_mq_hw_queue_mapped(hctx)))
+	if (unlikely(blk_mq_hctx_stopped(hctx) ||
+		     !blk_mq_hw_queue_mapped(hctx)))
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
@@ -938,7 +938,7 @@  void blk_mq_run_hw_queues(struct request_queue *q, bool async)
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if ((!blk_mq_hctx_has_pending(hctx) &&
 		    list_empty_careful(&hctx->dispatch)) ||
-		    test_bit(BLK_MQ_S_STOPPED, &hctx->state))
+		    blk_mq_hctx_stopped(hctx))
 			continue;
 
 		blk_mq_run_hw_queue(hctx, async);
@@ -988,7 +988,7 @@  void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
 	int i;
 
 	queue_for_each_hw_ctx(q, hctx, i) {
-		if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state))
+		if (!blk_mq_hctx_stopped(hctx))
 			continue;
 
 		clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
@@ -1332,7 +1332,7 @@  static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 		blk_mq_put_ctx(data.ctx);
 		if (!old_rq)
 			goto done;
-		if (test_bit(BLK_MQ_S_STOPPED, &data.hctx->state) ||
+		if (blk_mq_hctx_stopped(data.hctx) ||
 		    blk_mq_direct_issue_request(old_rq, &cookie) != 0)
 			blk_mq_insert_request(old_rq, false, true, true);
 		goto done;
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index dc75bea..76d1666 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -909,7 +909,7 @@  static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 	 * hctx that it really shouldn't.  The following check guards
 	 * against this rarity (albeit _not_ race-free).
 	 */
-	if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
+	if (unlikely(blk_mq_hctx_stopped(hctx)))
 		return BLK_MQ_RQ_QUEUE_BUSY;
 
 	if (ti->type->busy && ti->type->busy(ti))
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 535ab2e..bb000c3 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -239,6 +239,11 @@  int blk_mq_reinit_tagset(struct blk_mq_tag_set *set);
 
 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
 
+static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
+{
+	return test_bit(BLK_MQ_S_STOPPED, &hctx->state);
+}
+
 /*
  * Driver command data is immediately after the request. So subtract request
  * size to get back to the original request, add request size to get the PDU.