Messages in this thread | | | Date | Sat, 29 Aug 2009 20:43:27 -0400 | From | Douglas Gilbert <> | Subject | Re: [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit |
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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 <hch@lst.de> > > 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", > + bio->bi_sector, bio_sectors(bio)); > + > + bio->bi_size = 0; > + if (bio_add_pc_page(q, bio, page, sdp->sector_size, 0) < > + sdp->sector_size) > + return -EIO; > + > + return 0; > +} > + > static void sd_rescan(struct device *dev) > { > struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev); > @@ -1369,6 +1413,9 @@ static int read_capacity_16(struct scsi_ > sd_printk(KERN_NOTICE, sdkp, > "physical block alignment offset: %u\n", alignment); > > + if (buffer[14] & 0x80) > + sdkp->thin_provisioning = 1; > +
So you are checking the TPE bit (Thin Provisioning Enabled) but not the TPRZ bit (Thin Provisioning Read Zeros). Shouldn't there also be a sdkp->thin_provisioning_read_zeros bit defined in struct scsi_disk?
Is your application well defined when TPRZ==0 ?
Doug Gilbert
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