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Commit 26caddf2 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
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mmc: block: Fix unsupported parallel dispatch of requests 



The mmc block driver does not support parallel dispatch of requests. In
normal circumstances, all requests are anyway funneled through a single
work item, so parallel dispatch never happens. However it can happen if
there is no elevator.

Fix that by detecting if a dispatch is in progress and returning busy
(BLK_STS_RESOURCE) in that case

Fixes: 81196976 ("mmc: block: Add blk-mq support")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 17e96d85

drivers/mmc/core/queue.c

+7 −5
Original line number Diff line number Diff line
@@ -238,10 +238,6 @@ static void mmc_mq_exit_request(struct blk_mq_tag_set *set, struct request *req, 
	mmc_exit_request(mq->queue, req);

}



/*

 * We use BLK_MQ_F_BLOCKING and have only 1 hardware queue, which means requests

 * will not be dispatched in parallel.

 */

static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,

				    const struct blk_mq_queue_data *bd)

{
@@ -264,7 +260,7 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 


	spin_lock_irq(q->queue_lock);



	if (mq->recovery_needed) {

	if (mq->recovery_needed || mq->busy) {

		spin_unlock_irq(q->queue_lock);

		return BLK_STS_RESOURCE;

	}
@@ -291,6 +287,9 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 
		break;

	}



	/* Parallel dispatch of requests is not supported at the moment */

	mq->busy = true;



	mq->in_flight[issue_type] += 1;

	get_card = (mmc_tot_in_flight(mq) == 1);

	cqe_retune_ok = (mmc_cqe_qcnt(mq) == 1);
@@ -333,9 +332,12 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 
		mq->in_flight[issue_type] -= 1;

		if (mmc_tot_in_flight(mq) == 0)

			put_card = true;

		mq->busy = false;

		spin_unlock_irq(q->queue_lock);

		if (put_card)

			mmc_put_card(card, &mq->ctx);

	} else {

		WRITE_ONCE(mq->busy, false);

	}



	return ret;

drivers/mmc/core/queue.h

+1 −0
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ struct mmc_queue { 
	unsigned int		cqe_busy;

#define MMC_CQE_DCMD_BUSY	BIT(0)

#define MMC_CQE_QUEUE_FULL	BIT(1)

	bool			busy;

	bool			use_cqe;

	bool			recovery_needed;

	bool			in_recovery;