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.manzana...@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
h...@suse.de                                   +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

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