From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 4/4] block: add large command support Date: Mon, 14 Apr 2008 13:29:20 +0200 Message-ID: <20080414112919.GF12774@kernel.dk> References: <20080414010112W.tomof@acm.org> <1208170266-1676-1-git-send-email-fujita.tomonori@lab.ntt.co.jp> <1208170266-1676-2-git-send-email-fujita.tomonori@lab.ntt.co.jp> <1208170266-1676-3-git-send-email-fujita.tomonori@lab.ntt.co.jp> <1208170266-1676-4-git-send-email-fujita.tomonori@lab.ntt.co.jp> <1208170266-1676-5-git-send-email-fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([87.55.233.238]:21521 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752939AbYDNL31 (ORCPT ); Mon, 14 Apr 2008 07:29:27 -0400 Content-Disposition: inline In-Reply-To: <1208170266-1676-5-git-send-email-fujita.tomonori@lab.ntt.co.jp> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: FUJITA Tomonori Cc: linux-scsi@vger.kernel.org, bharrosh@panasas.com, linux-ide@vger.kernel.org On Mon, Apr 14 2008, FUJITA Tomonori wrote: > This patch changes rq->cmd from the static array to a pointer to > support large commands. > > We rarely handle large commands. So for optimization, a struct request > still has a static array for a command. rq_init sets rq->cmd pointer > to the static array. > > Signed-off-by: FUJITA Tomonori > Cc: Jens Axboe > --- > block/blk-core.c | 1 + > drivers/ide/ide-io.c | 1 + > include/linux/blkdev.h | 12 ++++++++++-- > 3 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 6669238..6f0968f 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -132,6 +132,7 @@ void rq_init(struct request_queue *q, struct request *rq) > rq->errors = 0; > rq->ref_count = 1; > rq->cmd_len = 0; > + rq->cmd = rq->__cmd; > memset(rq->cmd, 0, BLK_MAX_CDB); > rq->data_len = 0; > rq->extra_len = 0; > diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c > index 7153796..bac5ea1 100644 > --- a/drivers/ide/ide-io.c > +++ b/drivers/ide/ide-io.c > @@ -1595,6 +1595,7 @@ void ide_init_drive_cmd (struct request *rq) > { > memset(rq, 0, sizeof(*rq)); > rq->ref_count = 1; > + rq->cmd = rq->__cmd; > } > > EXPORT_SYMBOL(ide_init_drive_cmd); > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index b3a58ad..5710ae4 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -215,8 +215,9 @@ struct request { > /* > * when request is used as a packet command carrier > */ > - unsigned int cmd_len; > - unsigned char cmd[BLK_MAX_CDB]; > + unsigned short cmd_len; > + unsigned char __cmd[BLK_MAX_CDB]; > + unsigned char *cmd; > > unsigned int data_len; > unsigned int extra_len; /* length of alignment and padding */ > @@ -812,6 +813,13 @@ static inline void put_dev_sector(Sector p) > page_cache_release(p.v); > } > > +static inline void rq_set_cmd(struct request *rq, unsigned char *cmd, > + unsigned short cmd_len) > +{ > + rq->cmd = cmd; > + rq->cmd_len = cmd_len; > +} > + This is 100% identical to what I suggested be done instead, so of course I agree with this. -- Jens Axboe