lkml.org 
[lkml]   [2009]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit
    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





    \
     
     \ /
      Last update: 2009-08-30 02:45    [W:0.028 / U:60.804 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site