From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit Date: Sun, 30 Aug 2009 15:12:09 +0400 Message-ID: <4A9A5E89.7070204@ru.mvista.com> References: <20090829230332.017137693@bombadil.infradead.org> <20090829231121.713422216@bombadil.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090829231121.713422216@bombadil.infradead.org> Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig Cc: linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, liml@rtr.ca, jens.axboe@oracle.com, matthew@wil.cx, dwmw2@infradead.org List-Id: linux-scsi@vger.kernel.org Hello. Christoph Hellwig wrote: > Add a prepare_discard function to sd that sends a WRITE SAME request with > the unmap bit set to the device if it advertises thin provisioning support. > > > Signed-off-by: Christoph Hellwig > > Index: linux-2.6/drivers/scsi/sd.c > =================================================================== > --- linux-2.6.orig/drivers/scsi/sd.c 2009-08-29 19:19:36.067371669 -0300 > +++ linux-2.6/drivers/scsi/sd.c 2009-08-29 19:26:20.723754241 -0300 > @@ -911,6 +911,50 @@ static void sd_prepare_flush(struct requ > rq->cmd_len = 10; > } > > +static int sd_prepare_discard(struct request_queue *q, struct request *rq, > + struct bio *bio) > +{ > + struct scsi_device *sdp = q->queuedata; > + struct page *page = alloc_page(GFP_KERNEL); > + > + if (!page) > + return -ENOMEM; > + > + rq->cmd_type = REQ_TYPE_BLOCK_PC; > + rq->timeout = SD_TIMEOUT; > + rq->cmd[0] = WRITE_SAME_16; > + rq->cmd[1] = 0x8; /* UNMAP bit */ > + rq->cmd[2] = sizeof(bio->bi_sector) > 4 ? > + (unsigned char) (bio->bi_sector >> 56) & 0xff : 0; > + rq->cmd[3] = sizeof(bio->bi_sector) > 4 ? > + (unsigned char) (bio->bi_sector >> 48) & 0xff : 0; > + rq->cmd[4] = sizeof(bio->bi_sector) > 4 ? > + (unsigned char) (bio->bi_sector >> 40) & 0xff : 0; > + rq->cmd[5] = sizeof(bio->bi_sector) > 4 ? > + (unsigned char) (bio->bi_sector >> 32) & 0xff : 0; > + rq->cmd[6] = (unsigned char) (bio->bi_sector >> 24) & 0xff; > + rq->cmd[7] = (unsigned char) (bio->bi_sector >> 16) & 0xff; > + rq->cmd[8] = (unsigned char) (bio->bi_sector >> 8) & 0xff; > + rq->cmd[9] = (unsigned char) bio->bi_sector & 0xff; > + rq->cmd[10] = (unsigned char) (bio_sectors(bio) >> 24) & 0xff; > + rq->cmd[11] = (unsigned char) (bio_sectors(bio) >> 16) & 0xff; > + rq->cmd[12] = (unsigned char) (bio_sectors(bio) >> 8) & 0xff; > + rq->cmd[13] = (unsigned char) bio_sectors(bio) & 0xff; > + rq->cmd[14] = 0; > + rq->cmd[15] = 0; > + rq->cmd_len = 16; > + > + printk(KERN_INFO "umap, lba = 0x%lld, len = %d\n", > So, is it hex or decimal? :-) > + bio->bi_sector, bio_sectors(bio)); > Since bio->bi_sector can either be 4 or 8 bytes, you need a cast to unsigned long long here. MBR, Sergei