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scsi-mq: init sg in scsi_init_io.

PATCH Applied majianpeng 2 participants 2 messages Nov 29, 2013 – Dec 23, 2013 SCSI

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majianpeng

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#0 lore raw

PATCH 4/6 scsi-mq: init sg in scsi_init_io.

Make scsi-mq support blk-pc-command.

---
 drivers/scsi/scsi_lib.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/scsi/scsi_lib.c +3 -1
index bed596e..679e840 100644
@@ -1059,9 +1059,11 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 	/*
 	 * Use pre-allocation of cmd->sdb scatterlists with scsi-mq..
 	 */
-//FIXME: scsi-mq dif descriptor init within scsi_init_io
 	if (rq->mq_ctx) {
 		BUG_ON(rq->nr_phys_segments > SCSI_MAX_SG_SEGMENTS);
+		cmd->sdb.table.sgl = cmd->mq_sgl;
+		cmd->sdb.table.nents = rq->nr_phys_segments;
+		sg_init_table(cmd->sdb.table.sgl, rq->nr_phys_segments);
 		scsi_init_sgtable(rq, &cmd->sdb);
 		return BLKPREP_OK;
 	}
Signature · 1 line
1.7.10.4
#1 lore raw
Quoted 14 lines · majianpeng

Make scsi-mq support blk-pc-command.

---
 drivers/scsi/scsi_lib.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/scsi/scsi_lib.c +0 -0
index bed596e..679e840 100644
@@ -1059,9 +1059,11 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 	/*
 	 * Use pre-allocation of cmd->sdb scatterlists with scsi-mq..

drivers/scsi/scsi_lib.c int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) · line 1069

Quoted 10 lines
drivers/scsi/scsi_lib.c +3 -1
 	 */
-//FIXME: scsi-mq dif descriptor init within scsi_init_io
 	if (rq->mq_ctx) {
 		BUG_ON(rq->nr_phys_segments > SCSI_MAX_SG_SEGMENTS);
+		cmd->sdb.table.sgl = cmd->mq_sgl;
+		cmd->sdb.table.nents = rq->nr_phys_segments;
+		sg_init_table(cmd->sdb.table.sgl, rq->nr_phys_segments);
 		scsi_init_sgtable(rq, &cmd->sdb);
 		return BLKPREP_OK;
 	}

Doesn't seem to be necessary for TYPE_ROM either..?

So requests of REQ_TYPE_BLOCK_PC for TYPE_ROM with scsi-mq are having their sc->sdb.table setup from pre-allocated SGLs at the start of scsi_mq_queue_rq(), before q->prep_rq_fn() -> sr_prep_fn() -> scsi_setup_blk_pc_cmnd() is called.

--nab