scsi: ibmvfc: Store return code of H_FREE_SUB_CRQ during cleanup

The H_FREE_SUB_CRQ hypercall can return a retry delay return code that
indicates the call needs to be retried after a specific amount of time
delay. The error path to free a sub-CRQ in case of a failure during channel
registration fails to capture the return code of H_FREE_SUB_CRQ which will
result in the delay loop being skipped in the case of a retry delay return
code.

Store the return code result of the H_FREE_SUB_CRQ call such that the
return code check in the delay loop evaluates a meaningful value. Also, use
the rtas_busy_delay() to check the rc value and delay for the appropriate
amount of time.

Link: https://lore.kernel.org/r/20210302230543.9905-5-tyreld@linux.ibm.com
Fixes: 39e461fd ("scsi: ibmvfc: Map/request irq and register Sub-CRQ interrupt handler")
Reviewed-by: Brian King <brking@linux.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

@@ -21,6 +21,7 @@
 #include <linux/bsg-lib.h>
 #include <asm/firmware.h>
 #include <asm/irq.h>
+#include <asm/rtas.h>
 #include <asm/vio.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -5672,8 +5673,8 @@ static int ibmvfc_register_scsi_channel(struct ibmvfc_host *vhost,
 
 irq_failed:
 	do {
-		plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address, scrq->cookie);
-	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
+		rc = plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address, scrq->cookie);
+	} while (rtas_busy_delay(rc));
 reg_failed:
 	ibmvfc_free_queue(vhost, scrq);
 	LEAVE;