Re: [PATCH v4 1/4] block: Add iocontext priority to request

Hannes Reinecke
2016-10-14T05:55:01Z

On 10/13/2016 09:53 PM, Adam Manzanares wrote:
> Patch adds an association between iocontext ioprio and the ioprio of a
> request. This value is set in blk_rq_set_prio which takes the request and
> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the
> iopriority of the request is set as the iopriority of the ioc. In
> init_request_from_bio a check is made to see if the ioprio of the bio is
> valid and if so then the request prio comes from the bio.
>
> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com>
> ---
> block/blk-core.c | 4 +++-
> include/linux/blkdev.h | 14 ++++++++++++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 14d7c07..361b1b9 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op,
>
> blk_rq_init(q, rq);
> blk_rq_set_rl(rq, rl);
> + blk_rq_set_prio(rq, ioc);
> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED);
>
> /* init elvpriv */
> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio)
>
> req->errors = 0;
> req->__sector = bio->bi_iter.bi_sector;
> - req->ioprio = bio_prio(bio);
> + if (ioprio_valid(bio_prio(bio)))
> + req->ioprio = bio_prio(bio);
> blk_rq_bio_prep(req->q, req, bio);
> }
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index c47c358..9a0ceaa 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq)
> }
>
> /*
> + * blk_rq_set_prio - associate a request with prio from ioc
> + * @rq: request of interest
> + * @ioc: target iocontext
> + *
> + * Assocate request prio with ioc prio so request based drivers
> + * can leverage priority information.
> + */
> +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc)
> +{
> + if (ioc)
> + rq->ioprio = ioc->ioprio;
> +}
> +
> +/*
> * Request issue related functions.
> */
> extern struct request *blk_peek_request(struct request_queue *q);
>
Don't you need to check for 'ioprio_valid()' here, too?

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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