On Mon, 2018-11-19 at 12:51 +0900, Damien Le Moal wrote:
> Define get_current_ioprio() as an inline helper to obtain the caller
> I/O priority from its task I/O context. Use this helper in
> blk_init_request_from_bio() to set a request ioprio.
>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> ---
> block/blk-core.c | 6 +-----
> include/linux/ioprio.h | 13 +++++++++++++
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 492648c96992..4450d3c08f25 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -813,18 +813,14 @@ unsigned int blk_plug_queued_count(struct
> request_queue *q)
>
> void blk_init_request_from_bio(struct request *req, struct bio *bio)
> {
> - struct io_context *ioc = current->io_context;
> -
> if (bio->bi_opf & REQ_RAHEAD)
> req->cmd_flags |= REQ_FAILFAST_MASK;
>
> req->__sector = bio->bi_iter.bi_sector;
> if (ioprio_valid(bio_prio(bio)))
> req->ioprio = bio_prio(bio);
> - else if (ioc)
> - req->ioprio = ioc->ioprio;
> else
> - req->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
> + req->ioprio = get_current_ioprio();
> req->write_hint = bio->bi_write_hint;
> blk_rq_bio_prep(req->q, req, bio);
> }
> diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h
> index 9e30ed6443db..e9bfe6972aed 100644
> --- a/include/linux/ioprio.h
> +++ b/include/linux/ioprio.h
> @@ -70,6 +70,19 @@ static inline int task_nice_ioclass(struct
> task_struct *task)
> return IOPRIO_CLASS_BE;
> }
>
> +/*
> + * If the calling process has set an I/O priority, use that.
> Otherwise, return
> + * the default I/O priority.
> + */
> +static inline int get_current_ioprio(void)
> +{
> + struct io_context *ioc = current->io_context;
> +
> + if (ioc)
> + return ioc->ioprio;
> + return IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
Shouldn't this be IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM) to be
consistent with patch 3?
> +}
> +
> /*
> * For inheritance, return the highest of the two given priorities
> */
