4.18-stable review patch. If anyone has any objections, please let me know.
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From: Adrian Hunter adrian.hunter@intel.com
commit 26caddf274cf1e89fd4ce44ab2b8dbc7a7f97681 upstream.
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 # v4.16+ Signed-off-by: Adrian Hunter adrian.hunter@intel.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/mmc/core/queue.c | 12 +++++++----- drivers/mmc/core/queue.h | 1 + 2 files changed, 8 insertions(+), 5 deletions(-)
--- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c @@ -238,10 +238,6 @@ static void mmc_mq_exit_request(struct b 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(stru
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(stru 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(stru 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; --- 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;