Re: [PATCH] mmc: block: Fix unsupported parallel dispatch of requests
From: Ulf Hansson <hidden>
Date: 2018-08-21 14:19:17
On 21 August 2018 at 14:05, Adrian Hunter [off-list ref] wrote:
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: 81196976ed94 ("mmc: block: Add blk-mq support")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>Thanks, applied for fixes! Kind regards Uffe
quoted hunk ↗ jump to hunk
--- drivers/mmc/core/queue.c | 12 +++++++----- drivers/mmc/core/queue.h | 1 + 2 files changed, 8 insertions(+), 5 deletions(-)diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index 648eb6743ed5..6edffeed9953 100644 --- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c@@ -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;diff --git a/drivers/mmc/core/queue.h b/drivers/mmc/core/queue.h index 17e59d50b496..9bf3c9245075 100644 --- a/drivers/mmc/core/queue.h +++ b/drivers/mmc/core/queue.h@@ -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; --2.17.1