[PATCH 3/5] block: allow end_io based requests in the completion batch handling

[Anuj gupta]

On Tue, Sep 27, 2022 at 7:20 AM Jens Axboe <axboe at kernel.dk> wrote:
>
> With end_io handlers now being able to potentially pass ownership of
> the request upon completion, we can allow requests with end_io handlers
> in the batch completion handling.
>
> Co-developed-by: Stefan Roesch <shr at fb.com>
> Signed-off-by: Jens Axboe <axboe at kernel.dk>
> ---
>  block/blk-mq.c         | 13 +++++++++++--
>  include/linux/blk-mq.h |  3 ++-
>  2 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index a4e018c82b7c..a7dfe7a898a4 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -823,8 +823,10 @@ static void blk_complete_request(struct request *req)
>          * can find how many bytes remain in the request
>          * later.
>          */
> -       req->bio = NULL;
> -       req->__data_len = 0;
> +       if (!req->end_io) {
> +               req->bio = NULL;
> +               req->__data_len = 0;
> +       }
>  }
>
>  /**
> @@ -1055,6 +1057,13 @@ void blk_mq_end_request_batch(struct io_comp_batch *iob)
>
>                 rq_qos_done(rq->q, rq);
>
> +               /*
> +                * If end_io handler returns NONE, then it still has
> +                * ownership of the request.
> +                */
> +               if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
> +                       continue;
> +
>                 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
>                 if (!req_ref_put_and_test(rq))
>                         continue;
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index e6fa49dd6196..50811d0fb143 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -853,8 +853,9 @@ static inline bool blk_mq_add_to_batch(struct request *req,
>                                        struct io_comp_batch *iob, int ioerror,
>                                        void (*complete)(struct io_comp_batch *))
>  {
> -       if (!iob || (req->rq_flags & RQF_ELV) || req->end_io || ioerror)
> +       if (!iob || (req->rq_flags & RQF_ELV) || ioerror)
>                 return false;
> +
>         if (!iob->complete)
>                 iob->complete = complete;
>         else if (iob->complete != complete)
> --
> 2.35.1
>
Looks good.
Reviewed-by: Anuj Gupta <anuj20.g at samsung.com>

--
Anuj Gupta