From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 15/18] z2ram: dequeue in-flight request Date: Sat, 16 May 2009 16:54:56 +0400 Message-ID: <4A0EB7A0.10107@ru.mvista.com> References: <1241751256-17435-1-git-send-email-tj@kernel.org> <1241751256-17435-16-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1241751256-17435-16-git-send-email-tj@kernel.org> Sender: linux-scsi-owner@vger.kernel.org To: Tejun Heo Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, rusty@rustcorp.com.au, James.Bottomley@HansenPartnership.com, mike.miller@hp.com, donari75@gmail.com, paul.clements@steeleye.com, tim@cyberelk.net, Geert.Uytterhoeven@sonycom.com, davem@davemloft.net, Laurent@lvivier.info, jgarzik@pobox.com, jeremy@xensource.com, grant.likely@secretlab.ca, adrian@mcmen.demon.co.uk, sfr@canb.auug.org.au, bzolnier@gmail.com, petkovbb@googlemail.com, oakad@yahoo.com, drzeus@drzeus.cx, dwmw2@infradead.org, Markus.Lidel@shadowconnect.com, wein@de.ibm.com, schwidefsky@de.ibm.com, zaitcev@redhat.com, fujita.tomonori@lab.ntt.co.jp, axboe@kernel.dk List-Id: linux-ide@vger.kernel.org Hello. Tejun Heo wrote: > z2ram processes requests one-by-one synchronously and can be easily > converted to dequeueing model. Convert it. > > [ Impact: dequeue in-flight request ] > > Signed-off-by: Tejun Heo > --- > drivers/block/z2ram.c | 19 +++++++++++++++---- > 1 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c > index 6a13838..c909c1a 100644 > --- a/drivers/block/z2ram.c > +++ b/drivers/block/z2ram.c > @@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk; > static void do_z2_request(struct request_queue *q) > { > struct request *req; > - while ((req = elv_next_request(q)) != NULL) { > + > + req = elv_next_request(q); > + if (req) > + blkdev_dequeue_request(req); > + > + while (req) { > unsigned long start = blk_rq_pos(req) << 9; > unsigned long len = blk_rq_cur_bytes(req); > + int err = 0; > > if (start + len > z2ram_size) { > printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu, count=%u\n", > blk_rq_pos(req), blk_rq_cur_sectors(req)); > - __blk_end_request_cur(req, -EIO); > - continue; > + err = -EIO; > + goto done; > } > while (len) { > unsigned long addr = start & Z2RAM_CHUNKMASK; > @@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q) > start += size; > len -= size; > } > - __blk_end_request_cur(req, 0); > + done: > + if (!__blk_end_request_cur(req, err)) { > + req = elv_next_request(q); > + if (req) > + blkdev_dequeue_request(req); > + } > } > } > I'm sure this can be made more compact and without duplication (in many other cases as well): @@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk; static void do_z2_request(struct request_queue *q) { struct request *req; + while ((req = elv_next_request(q)) != NULL) { unsigned long start = blk_rq_pos(req) << 9; unsigned long len = blk_rq_cur_bytes(req); + blkdev_dequeue_request(req); + if (start + len > z2ram_size) { printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu, count=%u\n", blk_rq_pos(req), blk_rq_cur_sectors(req)); - __blk_end_request_cur(req, -EIO); - continue; + err = -EIO; + goto done; } while (len) { unsigned long addr = start & Z2RAM_CHUNKMASK; @@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q) start += size; len -= size; } - __blk_end_request_cur(req, 0); + done: + if (__blk_end_request_cur(req, err)); + break; } } MBR, Sergei