[170/244] [SCSI] libfc: Enhancement to RPORT state machine applicable only for VN2VN mode

[Greg KH]

3.0-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Kiran Patil <kiran.patil@xxxxxxxxx>

commit 480584818a4bb3655d8d0d875ed60b427fc61cc5 upstream.

Problem: Existing RPORT state machine continues witg FLOGI/PLOGI
process only after it receices beacon from other end. Once claiming
stage is over (either clain notify or clain repose), beacon is sent
and state machine enters into operational mode where it initiates the
rlogin process (FLOGI/PLOGI) to the peer but before this rlogin is
initiated, exitsing implementation checks if it received beacon from
other end, it beacon is not received yet, rlogin process is not
initiated. Other end initiates FLOGI but peer end keeps on rejecting
FLOGI, hence after 3 retries other end deletes associated rport, then
sends a beacon. Once the beacon is received, peer end now initiates
rlogin to the peer end but since associated rport is deleted FLOGI is
neither accepted nor the reject response send out because rport is
deleted. Hence unable to proceed withg FLOGI/PLOGI process and fails
to establish VN2VN connection.

Fix: VN2VN spec is not standard yet but based on exitsing collateral
on T11, it appears that, both end shall send beacon and enter into
'operational mode' without explictly waiting for beacon from other
end. Fix is to allow the RPORT login process as long as respective
RPORT is created (as part of claim notification / claim response) even
though state of RPORT is INIT. Means don't wait for beacon from peer
end, if peer end initiates FLOGI (means peer end exist and
responding).

Notes: This patch is preparing the FCoE stack for target wrt
offload. This is generic patch and harmless even if applied on storage
initiator because 'else if' condition of function 'fcoe_oem_found'
shall evaluate to TRUE only for targets.

Dependencies: None

Signed-off-by: Kiran Patil <kiran.patil@xxxxxxxxx>
Signed-off-by: Robert Love <robert.w.love@xxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/scsi/libfc/fc_rport.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -801,6 +801,20 @@ static void fc_rport_recv_flogi_req(stru
 
 	switch (rdata->rp_state) {
 	case RPORT_ST_INIT:
+		/*
+		 * If received the FLOGI request on RPORT which is INIT state
+		 * (means not transition to FLOGI either fc_rport timeout
+		 * function didn;t trigger or this end hasn;t received
+		 * beacon yet from other end. In that case only, allow RPORT
+		 * state machine to continue, otherwise fall through which
+		 * causes the code to send reject response.
+		 * NOTE; Not checking for FIP->state such as VNMP_UP or
+		 * VNMP_CLAIM because if FIP state is not one of those,
+		 * RPORT wouldn;t have created and 'rport_lookup' would have
+		 * failed anyway in that case.
+		 */
+		if (lport->point_to_multipoint)
+			break;
 	case RPORT_ST_DELETE:
 		mutex_unlock(&rdata->rp_mutex);
 		rjt_data.reason = ELS_RJT_FIP;


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