On 21 August 2018 at 14:05, Adrian Hunter <[email protected]> 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: [email protected]
> Signed-off-by: Adrian Hunter <[email protected]>
Thanks, applied for fixes!
Kind regards
Uffe
> ---
> 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
>
