From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Manzananares Subject: Re: [PATCH v4 1/4] block: Add iocontext priority to request Date: Fri, 14 Oct 2016 11:35:54 -0700 Message-ID: <20161014183554.GB6788@hgst.com> References: <1476388433-2539-1-git-send-email-adam.manzanares@hgst.com> <1476388433-2539-2-git-send-email-adam.manzanares@hgst.com> <733629ac-fb98-9acf-3b2b-e1554e839346@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <733629ac-fb98-9acf-3b2b-e1554e839346@suse.de> Sender: linux-kernel-owner@vger.kernel.org To: Hannes Reinecke Cc: Adam Manzanares , axboe@kernel.dk, tj@kernel.org, dan.j.williams@intel.com, martin.petersen@oracle.com, mchristi@redhat.com, toshi.kani@hpe.com, ming.lei@canonical.com, sathya.prakash@broadcom.com, chaitra.basappa@broadcom.com, suganath-prabu.subramani@broadcom.com, linux-block@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org The 10/14/2016 07:54, Hannes Reinecke wrote: > 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 > > --- > > 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? I poked around and it should be safe to not check for ioprio valid at this point. ioprio_valid only checks to see if the ioprio is not IOPRIO_CLASS_NONE. The request by default has a ioprio of none so if the ioc has ioprio of none we are not changing anything. The locations in the code that I found where the ioc prio is set are either filtered through the syscall handler, which checks for invalid priority combinations, or have valid priority values. Take care, Adam > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke Teamlead Storage & Networking > hare@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)