scsi: lpfc: Fix infinite wait when driver unregisters a remote NVME port.

When unregistering a remote port the lpfc driver would eventually wait
for the remoteport_unreg done callback. But the driver never completed
the io aborts that would allow the connections to terminate thus the
unreg done callback was never issued.  Turns out the coding style of the
driver allowed for the wait to occur on the same cpu that the deferred
isr is called on. The blocking for the wait, blocked the isr, and as the
isr didn't run, the io aborts wouldn't finish.

Turns out there was never a good reason to block waiting for the unreg
done in the first place. The driver can continue execution and the ref
counting within the driver will do the right thing.

Resolve by removing the wait and patching up a few cases where the ref
counting didn't look right - mainly cases where the remote port comes
back before the aborts had completed and the unreg done had been
called. Additionally, a few places which used pointer values to guide
driver actions weren't protected by lock, so correct those.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_nvme.c

@@ -201,16 +201,19 @@ lpfc_nvme_remoteport_delete(struct nvme_fc_remote_port *remoteport)
 	 * calling state machine to remove the node.
 	 */
 	lpfc_printf_vlog(vport, KERN_INFO, LOG_NVME_DISC,
-			"6146 remoteport delete complete %p\n",
+			"6146 remoteport delete of remoteport %p\n",
 			remoteport);
+	spin_lock_irq(&vport->phba->hbalock);
 	ndlp->nrport = NULL;
+	spin_unlock_irq(&vport->phba->hbalock);
+
+	/* Remove original register reference. The host transport
+	 * won't reference this rport/remoteport any further.
+	 */
 	lpfc_nlp_put(ndlp);
 
  rport_err:
-	/* This call has to execute as long as the rport is valid.
-	 * Release any threads waiting for the unreg to complete.
-	 */
-	complete(&rport->rport_unreg_done);
+	return;
 }
 
 static void
@@ -966,16 +969,10 @@ lpfc_nvme_io_cmd_wqe_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pwqeIn,
 	/* NVME targets need completion held off until the abort exchange
 	 * completes unless the NVME Rport is getting unregistered.
 	 */
-	if (!(lpfc_ncmd->flags & LPFC_SBUF_XBUSY) ||
-	    ndlp->upcall_flags & NLP_WAIT_FOR_UNREG) {
-		/* Clear the XBUSY flag to prevent double completions.
-		 * The nvme rport is getting unregistered and there is
-		 * no need to defer the IO.
-		 */
-		if (lpfc_ncmd->flags & LPFC_SBUF_XBUSY)
-			lpfc_ncmd->flags &= ~LPFC_SBUF_XBUSY;
 
+	if (!(lpfc_ncmd->flags & LPFC_SBUF_XBUSY)) {
 		nCmd->done(nCmd);
+		lpfc_ncmd->nvmeCmd = NULL;
 	}
 
 	spin_lock_irqsave(&phba->hbalock, flags);
@@ -2494,6 +2491,9 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 
 	rpinfo.port_name = wwn_to_u64(ndlp->nlp_portname.u.wwn);
 	rpinfo.node_name = wwn_to_u64(ndlp->nlp_nodename.u.wwn);
+	if (!ndlp->nrport)
+		lpfc_nlp_get(ndlp);
+
 	ret = nvme_fc_register_remoteport(localport, &rpinfo, &remote_port);
 	if (!ret) {
 		/* If the ndlp already has an nrport, this is just
@@ -2502,23 +2502,33 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 		 */
 		rport = remote_port->private;
 		if (ndlp->nrport) {
-			lpfc_printf_vlog(ndlp->vport, KERN_INFO,
-					 LOG_NVME_DISC,
-					 "6014 Rebinding lport to "
-					 "rport wwpn 0x%llx, "
-					 "Data: x%x x%x x%x x%06x\n",
-					 remote_port->port_name,
-					 remote_port->port_id,
-					 remote_port->port_role,
-					 ndlp->nlp_type,
-					 ndlp->nlp_DID);
+			if (ndlp->nrport == remote_port->private) {
+				/* Same remoteport.  Just reuse. */
+				lpfc_printf_vlog(ndlp->vport, KERN_INFO,
+						 LOG_NVME_DISC,
+						 "6014 Rebinding lport to "
+						 "remoteport %p wwpn 0x%llx, "
+						 "Data: x%x x%x %p x%x x%06x\n",
+						 remote_port,
+						 remote_port->port_name,
+						 remote_port->port_id,
+						 remote_port->port_role,
+						 ndlp,
+						 ndlp->nlp_type,
+						 ndlp->nlp_DID);
+				return 0;
+			}
 			prev_ndlp = rport->ndlp;
 
-			/* Sever the ndlp<->rport connection before dropping
-			 * the ndlp ref from register.
+			/* Sever the ndlp<->rport association
+			 * before dropping the ndlp ref from
+			 * register.
 			 */
+			spin_lock_irq(&vport->phba->hbalock);
 			ndlp->nrport = NULL;
+			spin_unlock_irq(&vport->phba->hbalock);
 			rport->ndlp = NULL;
+			rport->remoteport = NULL;
 			if (prev_ndlp)
 				lpfc_nlp_put(ndlp);
 		}
@@ -2526,19 +2536,20 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 		/* Clean bind the rport to the ndlp. */
 		rport->remoteport = remote_port;
 		rport->lport = lport;
-		rport->ndlp = lpfc_nlp_get(ndlp);
-		if (!rport->ndlp)
-			return -1;
+		rport->ndlp = ndlp;
+		spin_lock_irq(&vport->phba->hbalock);
 		ndlp->nrport = rport;
+		spin_unlock_irq(&vport->phba->hbalock);
 		lpfc_printf_vlog(vport, KERN_INFO,
 				 LOG_NVME_DISC | LOG_NODE,
 				 "6022 Binding new rport to "
-				 "lport %p Rport WWNN 0x%llx, "
+				 "lport %p Remoteport %p  WWNN 0x%llx, "
 				 "Rport WWPN 0x%llx DID "
-				 "x%06x Role x%x\n",
-				 lport,
+				 "x%06x Role x%x, ndlp %p\n",
+				 lport, remote_port,
 				 rpinfo.node_name, rpinfo.port_name,
-				 rpinfo.port_id, rpinfo.port_role);
+				 rpinfo.port_id, rpinfo.port_role,
+				 ndlp);
 	} else {
 		lpfc_printf_vlog(vport, KERN_ERR,
 				 LOG_NVME_DISC | LOG_NODE,
@@ -2553,47 +2564,6 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 #endif
 }
 
-/* lpfc_nvme_rport_unreg_wait - Wait for the host to complete an rport unreg.
- *
- * The driver has to wait for the host nvme transport to callback
- * indicating the remoteport has successfully unregistered all
- * resources.  Since this is an uninterruptible wait, loop every ten
- * seconds and print a message indicating no progress.
- *
- * An uninterruptible wait is used because of the risk of transport-to-
- * driver state mismatch.
- */
-void
-lpfc_nvme_rport_unreg_wait(struct lpfc_vport *vport,
-			   struct lpfc_nvme_rport *rport)
-{
-#if (IS_ENABLED(CONFIG_NVME_FC))
-	u32 wait_tmo;
-	int ret;
-
-	/* Host transport has to clean up and confirm requiring an indefinite
-	 * wait. Print a message if a 10 second wait expires and renew the
-	 * wait. This is unexpected.
-	 */
-	wait_tmo = msecs_to_jiffies(LPFC_NVME_WAIT_TMO * 1000);
-	while (true) {
-		ret = wait_for_completion_timeout(&rport->rport_unreg_done,
-						  wait_tmo);
-		if (unlikely(!ret)) {
-			lpfc_printf_vlog(vport, KERN_ERR, LOG_NVME_IOERR,
-					 "6174 Rport %p Remoteport %p wait "
-					 "timed out. Renewing.\n",
-					 rport, rport->remoteport);
-			continue;
-		}
-		break;
-	}
-	lpfc_printf_vlog(vport, KERN_INFO, LOG_NVME_IOERR,
-			 "6175 Rport %p Remoteport %p Complete Success\n",
-			 rport, rport->remoteport);
-#endif
-}
-
 /* lpfc_nvme_unregister_port - unbind the DID and port_role from this rport.
  *
  * There is no notion of Devloss or rport recovery from the current
@@ -2645,24 +2615,18 @@ lpfc_nvme_unregister_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 	 */
 
 	if (ndlp->nlp_type & NLP_NVME_TARGET) {
-		init_completion(&rport->rport_unreg_done);
-
 		/* No concern about the role change on the nvme remoteport.
 		 * The transport will update it.
 		 */
 		ndlp->upcall_flags |= NLP_WAIT_FOR_UNREG;
 		ret = nvme_fc_unregister_remoteport(remoteport);
-		if (ret != 0)
+		if (ret != 0) {
+			lpfc_nlp_put(ndlp);
 			lpfc_printf_vlog(vport, KERN_ERR, LOG_NVME_DISC,
 					 "6167 NVME unregister failed %d "
 					 "port_state x%x\n",
 					 ret, remoteport->port_state);
-		else
-			/* Wait for completion.  This either blocks
-			 * indefinitely or succeeds
-			 */
-			lpfc_nvme_rport_unreg_wait(vport, rport);
-		ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
+		}
 	}
 	return;
 
@@ -2721,8 +2685,11 @@ lpfc_sli4_nvme_xri_aborted(struct lpfc_hba *phba,
 			 * before the abort exchange command fully completes.
 			 * Once completed, it is available via the put list.
 			 */
-			nvme_cmd = lpfc_ncmd->nvmeCmd;
-			nvme_cmd->done(nvme_cmd);
+			if (lpfc_ncmd->nvmeCmd) {
+				nvme_cmd = lpfc_ncmd->nvmeCmd;
+				nvme_cmd->done(nvme_cmd);
+				lpfc_ncmd->nvmeCmd = NULL;
+			}
 			lpfc_release_nvme_buf(phba, lpfc_ncmd);
 			return;
 		}