Re: [PATCH V1 1/2] mmc: core: Check request type before completing the request

Adrian Hunter
2020-05-06T17:06:13Z

On 6/05/20 5:34 pm, Veerabhadrarao Badiganti wrote:
> In the request completion path with CQE, request type is being checked
> after the request is getting completed. This is resulting in returning
> the wrong request type and leading to the IO hang issue.
>
> ASYNC request type is getting returned for DCMD type requests.
> Because of this mismatch, mq->cqe_busy flag is never getting cleared
> and the driver is not invoking blk_mq_hw_run_queue. So requests are not
> getting dispatched to the LLD from the block layer.
>
> All these eventually leading to IO hang issues.
> So, get the request type before completing the request.
>
> Cc: <stable@vger.kernel.org> # v4.19+

The fixed commit was in 4.16

> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>

Fixes: 1e8e55b67030 ("mmc: block: Add CQE support")
Acked-by: Adrian Hunter <adrian.hunter@intel.com>

Thank you for finding this!

> ---
> drivers/mmc/core/block.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index 8499b56..c5367e2 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -1370,6 +1370,7 @@ static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
> struct mmc_request *mrq = &mqrq->brq.mrq;
> struct request_queue *q = req->q;
> struct mmc_host *host = mq->card->host;
> + enum mmc_issue_type issue_type = mmc_issue_type(mq, req);
> unsigned long flags;
> bool put_card;
> int err;
> @@ -1399,7 +1400,7 @@ static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
>
> spin_lock_irqsave(&mq->lock, flags);
>
> - mq->in_flight[mmc_issue_type(mq, req)] -= 1;
> + mq->in_flight[issue_type] -= 1;
>
> put_card = (mmc_tot_in_flight(mq) == 0);
>
>