scsi: lpfc: Fix premature rpi release for unsolicited TPLS and LS_RJT

A test scenario has a target issuing a TPLS after accepting the driver's
PRLI.  TPLS is not supported by the driver so it rejects the ELS.  However,
the reject was only happening on the primary N_Port.  If the TPLS was to a
NPIV vport, not only would it reject the ELS, but it would act on the TPLS,
starting devloss, then unregister from the SCSI transport and release the
node. When devloss expired, it would access the node again and cause a page
faul.

Fix by altering the NPIV code to recognize that a correctly registered node
can reject unsolicited ELS I/O and to not unregister with the SCSI
transport and tear the node down.  Add a check of the fc4_xpt_flags so that
only a zero value allows the unreg and teardown.

Link: https://lore.kernel.org/r/20210910233159.115896-4-jsmart2021@gmail.comCo-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_els.c

@@ -5295,6 +5295,7 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 	 */
 	if (phba->sli_rev == LPFC_SLI_REV4 &&
 	    (vport && vport->port_type == LPFC_NPIV_PORT) &&
+	    !(ndlp->fc4_xpt_flags & SCSI_XPT_REGD) &&
 	    ndlp->nlp_flag & NLP_RELEASE_RPI) {
 		lpfc_sli4_free_rpi(phba, ndlp->nlp_rpi);
 		spin_lock_irq(&ndlp->lock);
@@ -5598,11 +5599,12 @@ lpfc_els_rsp_reject(struct lpfc_vport *vport, uint32_t rejectError,
 	}
 
 	/* The NPIV instance is rejecting this unsolicited ELS. Make sure the
-	 * node's assigned RPI needs to be released as this node will get
-	 * freed.
+	 * node's assigned RPI gets released provided this node is not already
+	 * registered with the transport.
 	 */
 	if (phba->sli_rev == LPFC_SLI_REV4 &&
-	    vport->port_type == LPFC_NPIV_PORT) {
+	    vport->port_type == LPFC_NPIV_PORT &&
+	    !(ndlp->fc4_xpt_flags & SCSI_XPT_REGD)) {
 		spin_lock_irq(&ndlp->lock);
 		ndlp->nlp_flag |= NLP_RELEASE_RPI;
 		spin_unlock_irq(&ndlp->lock);