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Commit 055f6e18 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: Make q_usage_counter also track legacy requests 



This patch makes it possible to pause request allocation for
the legacy block layer by calling blk_mq_freeze_queue() and
blk_mq_unfreeze_queue().

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
[ bvanassche: Combined two patches into one, edited a comment and made sure
  REQ_NOWAIT is handled properly in blk_old_get_request() ]
Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Tested-by: default avatarMartin Steigerwald <martin@lichtvoll.de>
Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent eb619fdb

block/blk-core.c

+12 −0
Original line number Diff line number Diff line
@@ -612,6 +612,9 @@ void blk_set_queue_dying(struct request_queue *q) 
		}

		spin_unlock_irq(q->queue_lock);

	}



	/* Make blk_queue_enter() reexamine the DYING flag. */

	wake_up_all(&q->mq_freeze_wq);

}

EXPORT_SYMBOL_GPL(blk_set_queue_dying);
@@ -1398,16 +1401,22 @@ static struct request *blk_old_get_request(struct request_queue *q, 
					   unsigned int op, gfp_t gfp_mask)

{

	struct request *rq;

	int ret = 0;



	WARN_ON_ONCE(q->mq_ops);



	/* create ioc upfront */

	create_io_context(gfp_mask, q->node);



	ret = blk_queue_enter(q, !(gfp_mask & __GFP_DIRECT_RECLAIM) ||

			      (op & REQ_NOWAIT));

	if (ret)

		return ERR_PTR(ret);

	spin_lock_irq(q->queue_lock);

	rq = get_request(q, op, NULL, gfp_mask);

	if (IS_ERR(rq)) {

		spin_unlock_irq(q->queue_lock);

		blk_queue_exit(q);

		return rq;

	}
@@ -1579,6 +1588,7 @@ void __blk_put_request(struct request_queue *q, struct request *req) 
		blk_free_request(rl, req);

		freed_request(rl, sync, rq_flags);

		blk_put_rl(rl);

		blk_queue_exit(q);

	}

}

EXPORT_SYMBOL_GPL(__blk_put_request);
@@ -1860,8 +1870,10 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) 
	 * Grab a free request. This is might sleep but can not fail.

	 * Returns with the queue unlocked.

	 */

	blk_queue_enter_live(q);

	req = get_request(q, bio->bi_opf, bio, GFP_NOIO);

	if (IS_ERR(req)) {

		blk_queue_exit(q);

		__wbt_done(q->rq_wb, wb_acct);

		if (PTR_ERR(req) == -ENOMEM)

			bio->bi_status = BLK_STS_RESOURCE;

block/blk-mq.c

+2 −8
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ void blk_freeze_queue_start(struct request_queue *q) 
	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);

	if (freeze_depth == 1) {

		percpu_ref_kill(&q->q_usage_counter);

		if (q->mq_ops)

			blk_mq_run_hw_queues(q, false);

	}

}
@@ -256,13 +257,6 @@ void blk_mq_wake_waiters(struct request_queue *q) 
	queue_for_each_hw_ctx(q, hctx, i)

		if (blk_mq_hw_queue_mapped(hctx))

			blk_mq_tag_wakeup_all(hctx->tags, true);



	/*

	 * If we are called because the queue has now been marked as

	 * dying, we need to ensure that processes currently waiting on

	 * the queue are notified as well.

	 */

	wake_up_all(&q->mq_freeze_wq);

}



bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)