[SCSI] fc-transport: Close state transition-window during rport deletion.

Andrew Vasquez wrote:
> fc-transport: Close state transition-window during rport deletion.
>
> After an rport's state has transitioned to FC_PORTSTATE_BLOCKED,
> but, prior to making the upcall to 'block' the scsi-target
> associated with an rport, queued commands can recycle and
> ultimately run out of retries causing failures to propagate to
> upper-level drivers.  Close this transition-window by returning
> the non-'retries' modifying DID_IMM_RETRY status for submitted
> I/Os.

The same can happen for iscsi when transitioning from logged in
to failed and blocking the sdevs.

This patch converts iscsi and fc's transitions back to use DID_IMM_RETRY
instead of DID_TRANSPORT_DISRUPTED which has a limited number of retries
that we do not want to use for handling this race.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
[Addition of iscsi and fc port online devloss case conversion by Mike Christie]
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/scsi_transport_iscsi.c

@@ -357,7 +357,7 @@ int iscsi_session_chkready(struct iscsi_cls_session *session)
 		err = 0;
 		break;
 	case ISCSI_SESSION_FAILED:
-		err = DID_TRANSPORT_DISRUPTED << 16;
+		err = DID_IMM_RETRY << 16;
 		break;
 	case ISCSI_SESSION_FREE:
 		err = DID_TRANSPORT_FAILFAST << 16;

include/scsi/scsi_transport_fc.h

@@ -680,7 +680,7 @@ fc_remote_port_chkready(struct fc_rport *rport)
 		if (rport->roles & FC_PORT_ROLE_FCP_TARGET)
 			result = 0;
 		else if (rport->flags & FC_RPORT_DEVLOSS_PENDING)
-			result = DID_TRANSPORT_DISRUPTED << 16;
+			result = DID_IMM_RETRY << 16;
 		else
 			result = DID_NO_CONNECT << 16;
 		break;
@@ -688,7 +688,7 @@ fc_remote_port_chkready(struct fc_rport *rport)
 		if (rport->flags & FC_RPORT_FAST_FAIL_TIMEDOUT)
 			result = DID_TRANSPORT_FAILFAST << 16;
 		else
-			result = DID_TRANSPORT_DISRUPTED << 16;
+			result = DID_IMM_RETRY << 16;
 		break;
 	default:
 		result = DID_NO_CONNECT << 16;