block/scsi: Provide a limit on the number of integrity segments

Some controllers have a hardware limit on the number of protection
information scatter-gather list segments they can handle.

Introduce a max_integrity_segments limit in the block layer and provide
a new scsi_host_template setting that allows HBA drivers to provide a
value suitable for the hardware.

Add support for honoring the integrity segment limit when merging both
bios and requests.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
This commit is contained in:
Martin K. Petersen
2010-09-10 20:50:10 +02:00
committed by Jens Axboe
parent c8bf133682
commit 13f05c8d8e
12 changed files with 167 additions and 50 deletions
+18 -8
View File
@@ -968,11 +968,13 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
*/
int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
struct request *rq = cmd->request;
int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
if (error)
goto err_exit;
if (blk_bidi_rq(cmd->request)) {
if (blk_bidi_rq(rq)) {
struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
scsi_sdb_cache, GFP_ATOMIC);
if (!bidi_sdb) {
@@ -980,28 +982,28 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
goto err_exit;
}
cmd->request->next_rq->special = bidi_sdb;
error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
GFP_ATOMIC);
rq->next_rq->special = bidi_sdb;
error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
if (error)
goto err_exit;
}
if (blk_integrity_rq(cmd->request)) {
if (blk_integrity_rq(rq)) {
struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
int ivecs, count;
BUG_ON(prot_sdb == NULL);
ivecs = blk_rq_count_integrity_sg(cmd->request);
ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
error = BLKPREP_DEFER;
goto err_exit;
}
count = blk_rq_map_integrity_sg(cmd->request,
count = blk_rq_map_integrity_sg(rq->q, rq->bio,
prot_sdb->table.sgl);
BUG_ON(unlikely(count > ivecs));
BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
cmd->prot_sdb = prot_sdb;
cmd->prot_sdb->table.nents = count;
@@ -1625,6 +1627,14 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
SCSI_MAX_SG_CHAIN_SEGMENTS));
if (scsi_host_prot_dma(shost)) {
shost->sg_prot_tablesize =
min_not_zero(shost->sg_prot_tablesize,
(unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
}
blk_queue_max_hw_sectors(q, shost->max_sectors);
blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
blk_queue_segment_boundary(q, shost->dma_boundary);