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Commit 95f09684 authored May 27, 2014 by Jens Axboe

blk-mq: allow non-softirq completions



Right now we export two ways of completing a request:

1) blk_mq_complete_request(). This uses an IPI (if needed) and
   completes through q->softirq_done_fn(). It also works with
   timeouts.

2) blk_mq_end_io(). This completes inline, and ignores any timeout
   state of the request.

Let blk_mq_complete_request() handle non-softirq_done_fn completions
as well, by just completing inline. If a driver has enough completion
ports to place completions correctly, it need not define a
mq_ops->complete() and we can avoid an indirect function call by
doing the completion inline.

Signed-off-by: Jens Axboe <axboe@fb.com>

parent f14bbe77

block/blk-mq.c

+9 −3

Original line number	Original line	Diff line number	Diff line
	@@ -434,10 +434,16 @@ void __blk_mq_complete_request(struct request *rq)
	**/		**/
	void blk_mq_complete_request(struct request *rq)		void blk_mq_complete_request(struct request *rq)
	{		{
	if (unlikely(blk_should_fake_timeout(rq->q)))		struct request_queue *q = rq->q;

			if (unlikely(blk_should_fake_timeout(q)))
	return;		return;
	if (!blk_mark_rq_complete(rq))		if (!blk_mark_rq_complete(rq)) {
			if (q->softirq_done_fn)
	__blk_mq_complete_request(rq);		__blk_mq_complete_request(rq);
			else
			blk_mq_end_io(rq, rq->errors);
			}
	}		}
	EXPORT_SYMBOL(blk_mq_complete_request);		EXPORT_SYMBOL(blk_mq_complete_request);

include/linux/blk-mq.h

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -173,6 +173,10 @@ void __blk_mq_end_io(struct request *rq, int error);

	void blk_mq_requeue_request(struct request *rq);		void blk_mq_requeue_request(struct request *rq);

			/*
			* Complete request through potential IPI for right placement. Driver must
			* have defined a mq_ops->complete() hook for this.
			*/
	void blk_mq_complete_request(struct request *rq);		void blk_mq_complete_request(struct request *rq);

	void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);		void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);