scsi: megaraid_sas: Replace sdev_busy with local counter

Use local tracking of per-sdev outstanding command since sdev_busy in SCSI
mid layer is improved for performance reason using sbitmap (earlier it was
atomic variable).

Link: https://lore.kernel.org/r/20210122023317.687987-11-ming.lei@redhat.com
Cc: Omar Sandoval <osandov@fb.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Cc: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/megaraid/megaraid_sas.h

@@ -2019,10 +2019,12 @@ union megasas_frame {
  * struct MR_PRIV_DEVICE - sdev private hostdata
  * @is_tm_capable: firmware managed tm_capable flag
  * @tm_busy: TM request is in progress
+ * @sdev_priv_busy: pending command per sdev
  */
 struct MR_PRIV_DEVICE {
 	bool is_tm_capable;
 	bool tm_busy;
+	atomic_t sdev_priv_busy;
 	atomic_t r1_ldio_hint;
 	u8 interface_type;
 	u8 task_abort_tmo;

drivers/scsi/megaraid/megaraid_sas_fusion.c

@@ -220,6 +220,40 @@ megasas_clear_intr_fusion(struct megasas_instance *instance)
 	return 1;
 }
 
+static inline void
+megasas_sdev_busy_inc(struct megasas_instance *instance,
+		      struct scsi_cmnd *scmd)
+{
+	if (instance->perf_mode == MR_BALANCED_PERF_MODE) {
+		struct MR_PRIV_DEVICE *mr_device_priv_data =
+			scmd->device->hostdata;
+		atomic_inc(&mr_device_priv_data->sdev_priv_busy);
+	}
+}
+
+static inline void
+megasas_sdev_busy_dec(struct megasas_instance *instance,
+		      struct scsi_cmnd *scmd)
+{
+	if (instance->perf_mode == MR_BALANCED_PERF_MODE) {
+		struct MR_PRIV_DEVICE *mr_device_priv_data =
+			scmd->device->hostdata;
+		atomic_dec(&mr_device_priv_data->sdev_priv_busy);
+	}
+}
+
+static inline int
+megasas_sdev_busy_read(struct megasas_instance *instance,
+		       struct scsi_cmnd *scmd)
+{
+	if (instance->perf_mode == MR_BALANCED_PERF_MODE) {
+		struct MR_PRIV_DEVICE *mr_device_priv_data =
+			scmd->device->hostdata;
+		return atomic_read(&mr_device_priv_data->sdev_priv_busy);
+	}
+	return 0;
+}
+
 /**
  * megasas_get_cmd_fusion -	Get a command from the free pool
  * @instance:		Adapter soft state
@@ -357,15 +391,9 @@ megasas_get_msix_index(struct megasas_instance *instance,
 		       struct megasas_cmd_fusion *cmd,
 		       u8 data_arms)
 {
-	int sdev_busy;
-
-	/* TBD - if sml remove device_busy in future, driver
-	 * should track counter in internal structure.
-	 */
-	sdev_busy = atomic_read(&scmd->device->device_busy);
-
 	if (instance->perf_mode == MR_BALANCED_PERF_MODE &&
-	    sdev_busy > (data_arms * MR_DEVICE_HIGH_IOPS_DEPTH)) {
+	    (megasas_sdev_busy_read(instance, scmd) >
+	     (data_arms * MR_DEVICE_HIGH_IOPS_DEPTH))) {
 		cmd->request_desc->SCSIIO.MSIxIndex =
 			mega_mod64((atomic64_add_return(1, &instance->high_iops_outstanding) /
 					MR_HIGH_IOPS_BATCH_COUNT), instance->low_latency_index_start);
@@ -3390,6 +3418,7 @@ megasas_build_and_issue_cmd_fusion(struct megasas_instance *instance,
 	 * Issue the command to the FW
 	 */
 
+	megasas_sdev_busy_inc(instance, scmd);
 	megasas_fire_cmd_fusion(instance, req_desc);
 
 	if (r1_cmd)
@@ -3450,6 +3479,7 @@ megasas_complete_r1_command(struct megasas_instance *instance,
 		scmd_local->SCp.ptr = NULL;
 		megasas_return_cmd_fusion(instance, cmd);
 		scsi_dma_unmap(scmd_local);
+		megasas_sdev_busy_dec(instance, scmd_local);
 		scmd_local->scsi_done(scmd_local);
 	}
 }
@@ -3550,6 +3580,7 @@ complete_cmd_fusion(struct megasas_instance *instance, u32 MSIxIndex,
 				scmd_local->SCp.ptr = NULL;
 				megasas_return_cmd_fusion(instance, cmd_fusion);
 				scsi_dma_unmap(scmd_local);
+				megasas_sdev_busy_dec(instance, scmd_local);
 				scmd_local->scsi_done(scmd_local);
 			} else	/* Optimal VD - R1 FP command completion. */
 				megasas_complete_r1_command(instance, cmd_fusion);