[PATCH v2 04/15] lpfc: Fix crash when a fabric node is released prematurely.

[James Smart <jsmart2021@gmail.com>]

The driver's management of the fabric controller (aka pseudo-scsi
initiator) node in SLI3 mode is causing this crash. The crash occurs
because of a node reference imbalance that frees the fabric controller
node while devloss is outstanding from the SCSI transport.  This is
triggered by an odd behavior where the switch reacts to a rejected RDP
request with a PLOGI and nothing else, not even a LOGO.  The driver
ACKS the PLOGI and after successfully registering the RPI, incorrectly
registers the fabric controller node because it has the NLP_FC4_FCP
flag still set from the fabric controller PRLI.  If a LIP is issued,
the driver attempts to cleanup on Link Up and ends up executing too
many puts.

Fix by detecting the fabric node type and clearing out the nodes internal
flags that triggered a SCSI transport registration and subsequence
dev_loss event.  The driver cannot count on any persistence from
fabric controller nodes.

Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
---
 drivers/scsi/lpfc/lpfc_hbadisc.c   | 18 +++++++++++++-----
 drivers/scsi/lpfc/lpfc_nportdisc.c |  8 +++++++-
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index 2b6b5fc671fe..bcb5bf7e19dc 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -73,6 +73,16 @@ static void lpfc_unregister_fcfi_cmpl(struct lpfc_hba *, LPFC_MBOXQ_t *);
 static int lpfc_fcf_inuse(struct lpfc_hba *);
 static void lpfc_mbx_cmpl_read_sparam(struct lpfc_hba *, LPFC_MBOXQ_t *);
 
+static int
+lpfc_valid_xpt_node(struct lpfc_nodelist *ndlp)
+{
+	if (ndlp->nlp_fc4_type ||
+	    ndlp->nlp_DID == Fabric_DID ||
+	    ndlp->nlp_DID == NameServer_DID ||
+	    ndlp->nlp_DID == FDMI_DID)
+		return 1;
+	return 0;
+}
 /* The source of a terminate rport I/O is either a dev_loss_tmo
  * event or a call to fc_remove_host.  While the rport should be
  * valid during these downcalls, the transport can call twice
@@ -4318,7 +4328,8 @@ lpfc_nlp_state_cleanup(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	/* FCP and NVME Transport interface */
 	if ((old_state == NLP_STE_MAPPED_NODE ||
 	     old_state == NLP_STE_UNMAPPED_NODE)) {
-		if (ndlp->rport) {
+		if (ndlp->rport &&
+		    lpfc_valid_xpt_node(ndlp)) {
 			vport->phba->nport_event_cnt++;
 			lpfc_unregister_remote_port(ndlp);
 		}
@@ -4340,10 +4351,7 @@ lpfc_nlp_state_cleanup(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 
 	if (new_state ==  NLP_STE_MAPPED_NODE ||
 	    new_state == NLP_STE_UNMAPPED_NODE) {
-		if (ndlp->nlp_fc4_type ||
-		    ndlp->nlp_DID == Fabric_DID ||
-		    ndlp->nlp_DID == NameServer_DID ||
-		    ndlp->nlp_DID == FDMI_DID) {
+		if (lpfc_valid_xpt_node(ndlp)) {
 			vport->phba->nport_event_cnt++;
 			/*
 			 * Tell the fc transport about the port, if we haven't
diff --git a/drivers/scsi/lpfc/lpfc_nportdisc.c b/drivers/scsi/lpfc/lpfc_nportdisc.c
index 4961a8a55844..0d0d2ca1a5d8 100644
--- a/drivers/scsi/lpfc/lpfc_nportdisc.c
+++ b/drivers/scsi/lpfc/lpfc_nportdisc.c
@@ -1021,7 +1021,12 @@ lpfc_rcv_prli(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 			ndlp->nlp_fc4_type |= NLP_FC4_NVME;
 			lpfc_nlp_set_state(vport, ndlp, NLP_STE_UNMAPPED_NODE);
 		}
-		if (npr->prliType == PRLI_FCP_TYPE)
+
+		/* Fabric Controllers send FCP PRLI as an initiator but should
+		 * not get recognized as FCP type and registered with transport.
+		 */
+		if (npr->prliType == PRLI_FCP_TYPE &&
+		    !(ndlp->nlp_type & NLP_FABRIC))
 			ndlp->nlp_fc4_type |= NLP_FC4_FCP;
 	}
 	if (rport) {
@@ -2044,6 +2049,7 @@ lpfc_cmpl_reglogin_reglogin_issue(struct lpfc_vport *vport,
 		 * must complete PRLI.
 		 */
 		if (ndlp->nlp_type & NLP_FABRIC) {
+			ndlp->nlp_fc4_type &= ~NLP_FC4_FCP;
 			ndlp->nlp_prev_state = NLP_STE_REG_LOGIN_ISSUE;
 			lpfc_nlp_set_state(vport, ndlp, NLP_STE_UNMAPPED_NODE);
 		}
-- 
2.26.2