scsi: ufs: core: Use a host-wide tagset in SDB mode

In single-doorbell (SDB) mode there is only a single request queue. Hence,
it doesn't matter whether or not the SCSI host tagset is configured as
host-wide. Configure the host tagset as host-wide in SDB mode because this
enables a simplification of the hot path.

Signed-off-by: Bart Van Assche <[email protected]>
Reviewed-by: Peter Wang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

Author: bvanassche

drivers/ufs/core/ufs-mcq.c

@@ -444,7 +444,6 @@ EXPORT_SYMBOL_GPL(ufshcd_mcq_config_esi);
 
 int ufshcd_mcq_init(struct ufs_hba *hba)
 {
-	struct Scsi_Host *host = hba->host;
 	struct ufs_hw_queue *hwq;
 	int ret, i;
 
@@ -478,7 +477,6 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 		mutex_init(&hwq->sq_mutex);
 	}
 
-	host->host_tagset = 1;
 	return 0;
 }
 

drivers/ufs/core/ufshcd-priv.h

@@ -374,12 +374,7 @@ static inline bool ufs_is_valid_unit_desc_lun(struct ufs_dev_info *dev_info, u8
  */
 static inline struct scsi_cmnd *ufshcd_tag_to_cmd(struct ufs_hba *hba, u32 tag)
 {
-	/*
-	 * Host-wide tags are enabled in MCQ mode only. See also the
-	 * host->host_tagset assignment in ufs-mcq.c.
-	 */
-	struct blk_mq_tags *tags = hba->host->tag_set.shared_tags ?:
-					   hba->host->tag_set.tags[0];
+	struct blk_mq_tags *tags = hba->host->tag_set.shared_tags;
 	struct request *rq = blk_mq_tag_to_rq(tags, tag);
 
 	if (WARN_ON_ONCE(!rq))

drivers/ufs/core/ufshcd.c

@@ -9321,6 +9321,7 @@ static const struct scsi_host_template ufshcd_driver_template = {
 	.max_segment_size	= PRDT_DATA_BYTE_COUNT_MAX,
 	.max_sectors		= SZ_1M / SECTOR_SIZE,
 	.max_host_blocked	= 1,
+	.host_tagset		= true,
 	.track_queue_depth	= 1,
 	.skip_settle_delay	= 1,
 	.sdev_groups		= ufshcd_driver_groups,