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[SCSI] sd: Permit merged discard requests 

Support requests with more than one bio payload for discards. The total
number of bytes to be discarded is stored in req->__data_len and used in
sd_done() to complete the I/O.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Martin K. Petersen 2012-09-18 12:19:31 -04:00 committed by James Bottomley
parent 3c6bdaeab4
commit 26e85fcd15
1 changed files with 19 additions and 13 deletions
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32
drivers/scsi/sd.c
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@ -583,29 +583,26 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
}
/**
* scsi_setup_discard_cmnd - unmap blocks on thinly provisioned device
* sd_setup_discard_cmnd - unmap blocks on thinly provisioned device
* @sdp: scsi device to operate one
* @rq: Request to prepare
*
* Will issue either UNMAP or WRITE SAME(16) depending on preference
* indicated by target device.
**/
static int scsi_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
{
struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
struct bio *bio = rq->bio;
sector_t sector = bio->bi_sector;
unsigned int nr_sectors = bio_sectors(bio);
sector_t sector = blk_rq_pos(rq);
unsigned int nr_sectors = blk_rq_sectors(rq);
unsigned int nr_bytes = blk_rq_bytes(rq);
unsigned int len;
int ret;
char *buf;
struct page *page;
if (sdkp->device->sector_size == 4096) {
sector >>= 3;
nr_sectors >>= 3;
}
sector >>= ilog2(sdp->sector_size) - 9;
nr_sectors >>= ilog2(sdp->sector_size) - 9;
rq->timeout = SD_TIMEOUT;
memset(rq->cmd, 0, rq->cmd_len);
@ -660,6 +657,7 @@ static int scsi_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
blk_add_request_payload(rq, page, len);
ret = scsi_setup_blk_pc_cmnd(sdp, rq);
rq->buffer = page_address(page);
rq->__data_len = nr_bytes;
out:
if (ret != BLKPREP_OK) {
@ -712,7 +710,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
* block PC requests to make life easier.
*/
if (rq->cmd_flags & REQ_DISCARD) {
ret = scsi_setup_discard_cmnd(sdp, rq);
ret = sd_setup_discard_cmnd(sdp, rq);
goto out;
} else if (rq->cmd_flags & REQ_FLUSH) {
ret = scsi_setup_flush_cmnd(sdp, rq);
@ -1482,12 +1480,20 @@ static int sd_done(struct scsi_cmnd *SCpnt)
unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
struct scsi_sense_hdr sshdr;
struct scsi_disk *sdkp = scsi_disk(SCpnt->request->rq_disk);
struct request *req = SCpnt->request;
int sense_valid = 0;
int sense_deferred = 0;
unsigned char op = SCpnt->cmnd[0];
if ((SCpnt->request->cmd_flags & REQ_DISCARD) && !result)
scsi_set_resid(SCpnt, 0);
if (req->cmd_flags & REQ_DISCARD) {
if (!result) {
good_bytes = blk_rq_bytes(req);
scsi_set_resid(SCpnt, 0);
} else {
good_bytes = 0;
scsi_set_resid(SCpnt, blk_rq_bytes(req));
}
}
if (result) {
sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);