scsi: ibmvfc: Set and track hw queue in ibmvfc_event struct

Extract the hwq id from a SCSI command and store it in the ibmvfc_event
structure to identify which Sub-CRQ to send the command down when channels
are being utilized.

Link: https://lore.kernel.org/r/20210114203148.246656-15-tyreld@linux.ibm.comReviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ibmvscsi/ibmvfc.c

@@ -1483,6 +1483,7 @@ static void ibmvfc_init_event(struct ibmvfc_event *evt,
 		evt->_done = done;
 		evt->done = ibmvfc_locked_done;
 	}
+	evt->hwq = 0;
 }
 
 /**
@@ -1839,6 +1840,8 @@ static int ibmvfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 	struct ibmvfc_cmd *vfc_cmd;
 	struct ibmvfc_fcp_cmd_iu *iu;
 	struct ibmvfc_event *evt;
+	u32 tag_and_hwq = blk_mq_unique_tag(cmnd->request);
+	u16 hwq = blk_mq_unique_tag_to_hwq(tag_and_hwq);
 	int rc;
 
 	if (unlikely((rc = fc_remote_port_chkready(rport))) ||
@@ -1865,6 +1868,8 @@ static int ibmvfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 	}
 
 	vfc_cmd->correlation = cpu_to_be64(evt);
+	if (vhost->using_channels)
+		evt->hwq = hwq % vhost->scsi_scrqs.active_queues;
 
 	if (likely(!(rc = ibmvfc_map_sg_data(cmnd, evt, vfc_cmd, vhost->dev))))
 		return ibmvfc_send_event(evt, vhost, 0);

drivers/scsi/ibmvscsi/ibmvfc.h

@@ -753,6 +753,7 @@ struct ibmvfc_event {
 	struct completion comp;
 	struct completion *eh_comp;
 	struct timer_list timer;
+	u16 hwq;
 };
 
 /* a pool of event structs for use */