[SCSI] ibmvfc: Handle Virtual I/O Server reboot

If a Virtual I/O server is rebooted, the client fibre channel sees a
transport event on its CRQ, which causes it to attempt to reconnect
to the CRQ. For a period of time during the VIOS reboot, the client's
attempts to register the CRQ will return H_CLOSED, indicating the server
side is not currently registered. The ibmvfc driver was not handling
this well and was taking the virtual adapter offline. Fix this by
re-enabling our interrupt and waiting for the event on our CRQ
indicating the server is back, at which point we can reconnect.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/ibmvscsi/ibmvfc.c

@@ -4302,8 +4302,10 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
 		spin_unlock_irqrestore(vhost->host->host_lock, flags);
 		rc = ibmvfc_reset_crq(vhost);
 		spin_lock_irqsave(vhost->host->host_lock, flags);
-		if (rc || (rc = ibmvfc_send_crq_init(vhost)) ||
-		    (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {
+		if (rc == H_CLOSED)
+			vio_enable_interrupts(to_vio_dev(vhost->dev));
+		else if (rc || (rc = ibmvfc_send_crq_init(vhost)) ||
+			 (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {
 			ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
 			dev_err(vhost->dev, "Error after reset (rc=%d)\n", rc);
 		}