NVMe: Using PRACT bit to generate and verify PI by controller

This patch enables the PRCHK and reftag support when PRACT bit is set, and
block layer integrity is disabled.
Signed-off-by: Alok Pandey <pandey.alok@samsung.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/nvme-core.c

@@ -813,8 +813,7 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 	cmnd.rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
 	cmnd.rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
 
-	if (blk_integrity_rq(req)) {
-		cmnd.rw.metadata = cpu_to_le64(sg_dma_address(iod->meta_sg));
+	if (ns->ms) {
 		switch (ns->pi_type) {
 		case NVME_NS_DPS_PI_TYPE3:
 			control |= NVME_RW_PRINFO_PRCHK_GUARD;
@@ -827,8 +826,12 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 					nvme_block_nr(ns, blk_rq_pos(req)));
 			break;
 		}
-	} else if (ns->ms)
+		if (blk_integrity_rq(req))
+			cmnd.rw.metadata =
+				cpu_to_le64(sg_dma_address(iod->meta_sg));
+		else
 			control |= NVME_RW_PRINFO_PRACT;
+	}
 
 	cmnd.rw.control = cpu_to_le16(control);
 	cmnd.rw.dsmgmt = cpu_to_le32(dsmgmt);
@@ -2037,7 +2040,7 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 								!ns->ext)
 		nvme_init_integrity(ns);
 
-	if (ns->ms && !blk_get_integrity(disk))
+	if (ns->ms && !(ns->ms == 8 && ns->pi_type) && !blk_get_integrity(disk))
 		set_capacity(disk, 0);
 	else
 		set_capacity(disk, le64_to_cpup(&id->nsze) << (ns->lba_shift - 9));