[PATCH v4 5/7] scsi: pm8001: Use sas_task_find_rq() for tagging

[John Garry]

The request associated with a scsi command coming from the block layer
has a unique tag, so use that when possible for getting a CCB.

Unfortunately we don't support reserved commands in the SCSI midlayer yet,
so in the interim continue to manage those tags internally (along with
tags for private commands).

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
Reviewed-by: Jack Wang <jinpu.wang@xxxxxxxxx>
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
---
 drivers/scsi/pm8001/pm8001_init.c | 12 ++++--------
 drivers/scsi/pm8001/pm8001_sas.c  | 13 +++++++++----
 drivers/scsi/pm8001/pm8001_sas.h  | 11 ++++++++---
 drivers/scsi/pm8001/pm80xx_hwi.c  | 19 +++----------------
 4 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index 040a8280f23b..a1df61205b20 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -196,7 +196,7 @@ static void pm8001_free(struct pm8001_hba_info *pm8001_ha)
 	}
 	PM8001_CHIP_DISP->chip_iounmap(pm8001_ha);
 	flush_workqueue(pm8001_wq);
-	bitmap_free(pm8001_ha->tags);
+	bitmap_free(pm8001_ha->rsvd_tags);
 	kfree(pm8001_ha);
 }
 
@@ -1208,18 +1208,15 @@ static int pm8001_init_ccb_tag(struct pm8001_hba_info *pm8001_ha)
 	struct Scsi_Host *shost = pm8001_ha->shost;
 	struct device *dev = pm8001_ha->dev;
 	u32 max_out_io, ccb_count;
-	u32 can_queue;
 	int i;
 
 	max_out_io = pm8001_ha->main_cfg_tbl.pm80xx_tbl.max_out_io;
 	ccb_count = min_t(int, PM8001_MAX_CCB, max_out_io);
 
-	/* Update to the scsi host*/
-	can_queue = ccb_count - PM8001_RESERVE_SLOT;
-	shost->can_queue = can_queue;
+	shost->can_queue = ccb_count - PM8001_RESERVE_SLOT;
 
-	pm8001_ha->tags = bitmap_zalloc(ccb_count, GFP_KERNEL);
-	if (!pm8001_ha->tags)
+	pm8001_ha->rsvd_tags = bitmap_zalloc(PM8001_RESERVE_SLOT, GFP_KERNEL);
+	if (!pm8001_ha->rsvd_tags)
 		goto err_out;
 
 	/* Memory region for ccb_info*/
@@ -1244,7 +1241,6 @@ static int pm8001_init_ccb_tag(struct pm8001_hba_info *pm8001_ha)
 		pm8001_ha->ccb_info[i].task = NULL;
 		pm8001_ha->ccb_info[i].ccb_tag = PM8001_INVALID_TAG;
 		pm8001_ha->ccb_info[i].device = NULL;
-		++pm8001_ha->tags_num;
 	}
 
 	return 0;
diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
index c9fa3328f3fa..2359e827c9e6 100644
--- a/drivers/scsi/pm8001/pm8001_sas.c
+++ b/drivers/scsi/pm8001/pm8001_sas.c
@@ -65,9 +65,12 @@ static int pm8001_find_tag(struct sas_task *task, u32 *tag)
   */
 void pm8001_tag_free(struct pm8001_hba_info *pm8001_ha, u32 tag)
 {
-	void *bitmap = pm8001_ha->tags;
+	void *bitmap = pm8001_ha->rsvd_tags;
 	unsigned long flags;
 
+	if (tag >= PM8001_RESERVE_SLOT)
+		return;
+
 	spin_lock_irqsave(&pm8001_ha->bitmap_lock, flags);
 	__clear_bit(tag, bitmap);
 	spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
@@ -80,18 +83,20 @@ void pm8001_tag_free(struct pm8001_hba_info *pm8001_ha, u32 tag)
   */
 int pm8001_tag_alloc(struct pm8001_hba_info *pm8001_ha, u32 *tag_out)
 {
-	void *bitmap = pm8001_ha->tags;
+	void *bitmap = pm8001_ha->rsvd_tags;
 	unsigned long flags;
 	unsigned int tag;
 
 	spin_lock_irqsave(&pm8001_ha->bitmap_lock, flags);
-	tag = find_first_zero_bit(bitmap, pm8001_ha->tags_num);
-	if (tag >= pm8001_ha->tags_num) {
+	tag = find_first_zero_bit(bitmap, PM8001_RESERVE_SLOT);
+	if (tag >= PM8001_RESERVE_SLOT) {
 		spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
 		return -SAS_QUEUE_FULL;
 	}
 	__set_bit(tag, bitmap);
 	spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
+
+	/* reserved tags are in the lower region of the tagset */
 	*tag_out = tag;
 	return 0;
 }
diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
index ecb98bc5a8d0..cf5f1b091959 100644
--- a/drivers/scsi/pm8001/pm8001_sas.h
+++ b/drivers/scsi/pm8001/pm8001_sas.h
@@ -510,8 +510,7 @@ struct pm8001_hba_info {
 	u32			chip_id;
 	const struct pm8001_chip_info	*chip;
 	struct completion	*nvmd_completion;
-	int			tags_num;
-	unsigned long		*tags;
+	unsigned long		*rsvd_tags;
 	struct pm8001_phy	phy[PM8001_MAX_PHYS];
 	struct pm8001_port	port[PM8001_MAX_PHYS];
 	u32			id;
@@ -736,9 +735,15 @@ pm8001_ccb_alloc(struct pm8001_hba_info *pm8001_ha,
 		 struct pm8001_device *dev, struct sas_task *task)
 {
 	struct pm8001_ccb_info *ccb;
+	struct request *rq = NULL;
 	u32 tag;
 
-	if (pm8001_tag_alloc(pm8001_ha, &tag)) {
+	if (task)
+		rq = sas_task_find_rq(task);
+
+	if (rq) {
+		tag = rq->tag + PM8001_RESERVE_SLOT;
+	} else if (pm8001_tag_alloc(pm8001_ha, &tag)) {
 		pm8001_dbg(pm8001_ha, FAIL, "Failed to allocate a tag\n");
 		return NULL;
 	}
diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
index 4484c498bcb6..bc71db442dd9 100644
--- a/drivers/scsi/pm8001/pm80xx_hwi.c
+++ b/drivers/scsi/pm8001/pm80xx_hwi.c
@@ -4247,25 +4247,12 @@ static int check_enc_sat_cmd(struct sas_task *task)
 
 static u32 pm80xx_chip_get_q_index(struct sas_task *task)
 {
-	struct scsi_cmnd *scmd = NULL;
-	u32 blk_tag;
+	struct request *rq = sas_task_find_rq(task);
 
-	if (task->uldd_task) {
-		struct ata_queued_cmd *qc;
-
-		if (dev_is_sata(task->dev)) {
-			qc = task->uldd_task;
-			scmd = qc->scsicmd;
-		} else {
-			scmd = task->uldd_task;
-		}
-	}
-
-	if (!scmd)
+	if (!rq)
 		return 0;
 
-	blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
-	return blk_mq_unique_tag_to_hwq(blk_tag);
+	return blk_mq_unique_tag_to_hwq(blk_mq_unique_tag(rq));
 }
 
 /**
-- 
2.35.3