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authorChristoph Hellwig <hch@lst.de>2014-06-28 14:22:22 +0400
committerChristoph Hellwig <hch@lst.de>2014-07-18 00:12:47 +0400
commit59b1134c5a2aab2c70725af83d2e2d1c71c509ca (patch)
treeda9f4546991926e00f7215cfe058c1e3e7aeeabd /drivers/scsi/sd.c
parenta118c6c1d907e52286df25ee1e8b217f25d6f73d (diff)
downloadlinux-59b1134c5a2aab2c70725af83d2e2d1c71c509ca.tar.xz
sd: don't use scsi_setup_blk_pc_cmnd for write same requests
Simplify handling of write same 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: Webb Scales <webbnh@hp.com>
Diffstat (limited to 'drivers/scsi/sd.c')
-rw-r--r--drivers/scsi/sd.c44
1 files changed, 28 insertions, 16 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 18ca21fd7559..aefedf4fbb2b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -799,14 +799,15 @@ out:
/**
* sd_setup_write_same_cmnd - write the same data to multiple blocks
- * @sdp: scsi device to operate one
- * @rq: Request to prepare
+ * @cmd: command to prepare
*
* Will issue either WRITE SAME(10) or WRITE SAME(16) depending on
* preference indicated by target device.
**/
-static int sd_setup_write_same_cmnd(struct scsi_device *sdp, struct request *rq)
+static int sd_setup_write_same_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);
struct bio *bio = rq->bio;
sector_t sector = blk_rq_pos(rq);
@@ -822,25 +823,36 @@ static int sd_setup_write_same_cmnd(struct scsi_device *sdp, struct request *rq)
sector >>= ilog2(sdp->sector_size) - 9;
nr_sectors >>= ilog2(sdp->sector_size) - 9;
- rq->__data_len = sdp->sector_size;
rq->timeout = SD_WRITE_SAME_TIMEOUT;
- memset(rq->cmd, 0, rq->cmd_len);
if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff) {
- rq->cmd_len = 16;
- rq->cmd[0] = WRITE_SAME_16;
- 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;
+ put_unaligned_be64(sector, &cmd->cmnd[2]);
+ put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);
} else {
- rq->cmd_len = 10;
- rq->cmd[0] = WRITE_SAME;
- put_unaligned_be32(sector, &rq->cmd[2]);
- put_unaligned_be16(nr_sectors, &rq->cmd[7]);
+ cmd->cmd_len = 10;
+ cmd->cmnd[0] = WRITE_SAME;
+ put_unaligned_be32(sector, &cmd->cmnd[2]);
+ put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);
}
- ret = scsi_setup_blk_pc_cmnd(sdp, rq);
- rq->__data_len = nr_bytes;
+ cmd->transfersize = sdp->sector_size;
+ cmd->allowed = rq->retries;
+ /*
+ * For WRITE_SAME the data transferred in the DATA IN buffer is
+ * different from the amount of data actually written to the target.
+ *
+ * We set up __data_len to the amount of data transferred from the
+ * DATA IN buffer so that blk_rq_map_sg set up the proper S/G list
+ * to transfer a single sector of data first, but then reset it to
+ * the amount of data to be written right after so that the I/O path
+ * knows how much to actually write.
+ */
+ rq->__data_len = sdp->sector_size;
+ ret = scsi_init_io(cmd, GFP_ATOMIC);
+ rq->__data_len = nr_bytes;
return ret;
}
@@ -894,7 +906,7 @@ static int sd_init_command(struct scsi_cmnd *SCpnt)
ret = sd_setup_discard_cmnd(sdp, rq);
goto out;
} else if (rq->cmd_flags & REQ_WRITE_SAME) {
- ret = sd_setup_write_same_cmnd(sdp, rq);
+ ret = sd_setup_write_same_cmnd(SCpnt);
goto out;
} else if (rq->cmd_flags & REQ_FLUSH) {
ret = sd_setup_flush_cmnd(SCpnt);