[PATCH V2 15/25] smartpqi: fix host qdepth limit

[Don Brace <don.brace@xxxxxxxxxxxxx>]

From: Mahesh Rajashekhara <mahesh.rajashekhara@xxxxxxxxxxxxx>

* Correct scsi-mid-layer sending more requests than
  exposed host Q depth causing firmware ASSERT issue.
  * Add host Qdepth counter.

Reviewed-by: Scott Benesh <scott.benesh@xxxxxxxxxxxxx>
Reviewed-by: Scott Teel <scott.teel@xxxxxxxxxxxxx>
Reviewed-by: Kevin Barnett <kevin.barnett@xxxxxxxxxxxxx>
Signed-off-by: Mahesh Rajashekhara <mahesh.rajashekhara@xxxxxxxxxxxxx>
Signed-off-by: Don Brace <don.brace@xxxxxxxxxxxxx>
---
 drivers/scsi/smartpqi/smartpqi.h      |    2 ++
 drivers/scsi/smartpqi/smartpqi_init.c |   19 ++++++++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/smartpqi/smartpqi.h b/drivers/scsi/smartpqi/smartpqi.h
index 0b94c755a74c..c3b103b15924 100644
--- a/drivers/scsi/smartpqi/smartpqi.h
+++ b/drivers/scsi/smartpqi/smartpqi.h
@@ -1345,6 +1345,8 @@ struct pqi_ctrl_info {
 	struct work_struct ofa_quiesce_work;
 	u32		ofa_bytes_requested;
 	u16		ofa_cancel_reason;
+
+	atomic_t	total_scmds_outstanding;
 };
 
 enum pqi_ctrl_mode {
diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index af2ef5b5d019..b9c50411a4e2 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -5572,6 +5572,8 @@ static inline bool pqi_is_bypass_eligible_request(struct scsi_cmnd *scmd)
 void pqi_prep_for_scsi_done(struct scsi_cmnd *scmd)
 {
 	struct pqi_scsi_dev *device;
+	struct pqi_ctrl_info *ctrl_info;
+	struct Scsi_Host *shost;
 
 	if (!scmd->device) {
 		set_host_byte(scmd, DID_NO_CONNECT);
@@ -5584,7 +5586,11 @@ void pqi_prep_for_scsi_done(struct scsi_cmnd *scmd)
 		return;
 	}
 
+	shost = scmd->device->host;
+	ctrl_info = shost_to_hba(shost);
+
 	atomic_dec(&device->scsi_cmds_outstanding);
+	atomic_dec(&ctrl_info->total_scmds_outstanding);
 }
 
 static bool pqi_is_parity_write_stream(struct pqi_ctrl_info *ctrl_info,
@@ -5672,6 +5678,7 @@ static int pqi_scsi_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scm
 	bool raid_bypassed;
 
 	device = scmd->device->hostdata;
+	ctrl_info = shost_to_hba(shost);
 
 	if (!device) {
 		set_host_byte(scmd, DID_NO_CONNECT);
@@ -5680,8 +5687,11 @@ static int pqi_scsi_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scm
 	}
 
 	atomic_inc(&device->scsi_cmds_outstanding);
-
-	ctrl_info = shost_to_hba(shost);
+	if (atomic_inc_return(&ctrl_info->total_scmds_outstanding) >
+		ctrl_info->scsi_ml_can_queue) {
+		rc = SCSI_MLQUEUE_HOST_BUSY;
+		goto out;
+	}
 
 	if (pqi_ctrl_offline(ctrl_info) || pqi_device_in_remove(device)) {
 		set_host_byte(scmd, DID_NO_CONNECT);
@@ -5724,8 +5734,10 @@ static int pqi_scsi_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scm
 	}
 
 out:
-	if (rc)
+	if (rc) {
 		atomic_dec(&device->scsi_cmds_outstanding);
+		atomic_dec(&ctrl_info->total_scmds_outstanding);
+	}
 
 	return rc;
 }
@@ -8048,6 +8060,7 @@ static struct pqi_ctrl_info *pqi_alloc_ctrl_info(int numa_node)
 
 	INIT_WORK(&ctrl_info->event_work, pqi_event_worker);
 	atomic_set(&ctrl_info->num_interrupts, 0);
+	atomic_set(&ctrl_info->total_scmds_outstanding, 0);
 
 	INIT_DELAYED_WORK(&ctrl_info->rescan_work, pqi_rescan_worker);
 	INIT_DELAYED_WORK(&ctrl_info->update_time_work, pqi_update_time_worker);