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sd: don't use scsi_setup_blk_pc_cmnd for discard requests 

Simplify handling of discard requests by setting up the command directly
instead of initializing request fields and then calling
scsi_setup_blk_pc_cmnd to propagate the information into the command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
This commit is contained in:
Christoph Hellwig 2014-06-28 12:35:13 +02:00
parent 59b1134c5a
commit 6a7b43985d
1 changed files with 31 additions and 19 deletions
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50
drivers/scsi/sd.c
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@ -691,8 +691,10 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
* Will issue either UNMAP or WRITE SAME(16) depending on preference
* indicated by target device.
**/
static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
static int sd_setup_discard_cmnd(struct scsi_cmnd *cmd)
{
struct request *rq = cmd->request;
struct scsi_device *sdp = cmd->device;
struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
sector_t sector = blk_rq_pos(rq);
unsigned int nr_sectors = blk_rq_sectors(rq);
@ -704,9 +706,6 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
sector >>= ilog2(sdp->sector_size) - 9;
nr_sectors >>= ilog2(sdp->sector_size) - 9;
rq->timeout = SD_TIMEOUT;
memset(rq->cmd, 0, rq->cmd_len);
page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
if (!page)
@ -716,9 +715,9 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
case SD_LBP_UNMAP:
buf = page_address(page);
rq->cmd_len = 10;
rq->cmd[0] = UNMAP;
rq->cmd[8] = 24;
cmd->cmd_len = 10;
cmd->cmnd[0] = UNMAP;
cmd->cmnd[8] = 24;
put_unaligned_be16(6 + 16, &buf[0]);
put_unaligned_be16(16, &buf[2]);
@ -729,23 +728,23 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
break;
case SD_LBP_WS16:
rq->cmd_len = 16;
rq->cmd[0] = WRITE_SAME_16;
rq->cmd[1] = 0x8; /* UNMAP */
put_unaligned_be64(sector, &rq->cmd[2]);
put_unaligned_be32(nr_sectors, &rq->cmd[10]);
cmd->cmd_len = 16;
cmd->cmnd[0] = WRITE_SAME_16;
cmd->cmnd[1] = 0x8; /* UNMAP */
put_unaligned_be64(sector, &cmd->cmnd[2]);
put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);
len = sdkp->device->sector_size;
break;
case SD_LBP_WS10:
case SD_LBP_ZERO:
rq->cmd_len = 10;
rq->cmd[0] = WRITE_SAME;
cmd->cmd_len = 10;
cmd->cmnd[0] = WRITE_SAME;
if (sdkp->provisioning_mode == SD_LBP_WS10)
rq->cmd[1] = 0x8; /* UNMAP */
put_unaligned_be32(sector, &rq->cmd[2]);
put_unaligned_be16(nr_sectors, &rq->cmd[7]);
cmd->cmnd[1] = 0x8; /* UNMAP */
put_unaligned_be32(sector, &cmd->cmnd[2]);
put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);
len = sdkp->device->sector_size;
break;
@ -756,8 +755,21 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
}
rq->completion_data = page;
rq->timeout = SD_TIMEOUT;
cmd->transfersize = len;
cmd->allowed = rq->retries;
/*
* Initially __data_len is set to the amount of data that needs to be
* transferred to the target. This amount depends on whether WRITE SAME
* or UNMAP is being used. After the scatterlist has been mapped by
* scsi_init_io() we set __data_len to the size of the area to be
* discarded on disk. This allows us to report completion on the full
* amount of blocks described by the request.
*/
blk_add_request_payload(rq, page, len);
ret = scsi_setup_blk_pc_cmnd(sdp, rq);
ret = scsi_init_io(cmd, GFP_ATOMIC);
rq->__data_len = nr_bytes;
out:
@ -903,7 +915,7 @@ static int sd_init_command(struct scsi_cmnd *SCpnt)
* block PC requests to make life easier.
*/
if (rq->cmd_flags & REQ_DISCARD) {
ret = sd_setup_discard_cmnd(sdp, rq);
ret = sd_setup_discard_cmnd(SCpnt);
goto out;
} else if (rq->cmd_flags & REQ_WRITE_SAME) {
ret = sd_setup_write_same_cmnd(SCpnt);