scsi: rdac: Fix sshdr use

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when we get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20231004210013.5601-6-michael.christie@oracle.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: mikechristie

drivers/scsi/device_handler/scsi_dh_rdac.c

@@ -530,7 +530,7 @@ static void send_mode_select(struct work_struct *work)
 		container_of(work, struct rdac_controller, ms_work);
 	struct scsi_device *sdev = ctlr->ms_sdev;
 	struct rdac_dh_data *h = sdev->handler_data;
-	int err, retry_cnt = RDAC_RETRY_COUNT;
+	int rc, err, retry_cnt = RDAC_RETRY_COUNT;
 	struct rdac_queue_data *tmp, *qdata;
 	LIST_HEAD(list);
 	unsigned char cdb[MAX_COMMAND_SIZE];
@@ -558,13 +558,16 @@ static void send_mode_select(struct work_struct *work)
 		(char *) h->ctlr->array_name, h->ctlr->index,
 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
 
-	if (!scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
-			      RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args)) {
+	rc = scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
+			      RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args);
+	if (!rc) {
 		h->state = RDAC_STATE_ACTIVE;
 		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
 				"MODE_SELECT completed",
 				(char *) h->ctlr->array_name, h->ctlr->index);
 		err = SCSI_DH_OK;
+	} else if (rc < 0) {
+		err = SCSI_DH_IO;
 	} else {
 		err = mode_select_handle_sense(sdev, &sshdr);
 		if (err == SCSI_DH_RETRY && retry_cnt--)