scsi: lpfc: Fix kernel Oops due to null pring pointers

Driver is hitting null pring pointers in lpfc_do_work().

Pointer assignment occurs based on SLI-revision. If recovering after an
error, its possible the sli revision for the port was cleared, making the
lpfc_phba_elsring() not return a ring pointer, thus the null pointer.

Add SLI revision checking to lpfc_phba_elsring() and status checking to all
callers.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc.h

@@ -1277,6 +1277,12 @@ lpfc_sli_read_hs(struct lpfc_hba *phba)
 static inline struct lpfc_sli_ring *
 lpfc_phba_elsring(struct lpfc_hba *phba)
 {
+	/* Return NULL if sli_rev has become invalid due to bad fw */
+	if (phba->sli_rev != LPFC_SLI_REV4  &&
+	    phba->sli_rev != LPFC_SLI_REV3  &&
+	    phba->sli_rev != LPFC_SLI_REV2)
+		return NULL;
+
 	if (phba->sli_rev == LPFC_SLI_REV4) {
 		if (phba->sli4_hba.els_wq)
 			return phba->sli4_hba.els_wq->pring;

drivers/scsi/lpfc/lpfc_els.c

@@ -1343,6 +1343,8 @@ lpfc_els_abort_flogi(struct lpfc_hba *phba)
 			Fabric_DID);
 
 	pring = lpfc_phba_elsring(phba);
+	if (unlikely(!pring))
+		return -EIO;
 
 	/*
 	 * Check the txcmplq for an iocb that matches the nport the driver is

drivers/scsi/lpfc/lpfc_init.c

@@ -1797,7 +1797,12 @@ lpfc_sli4_port_sta_fn_reset(struct lpfc_hba *phba, int mbx_action,
 	lpfc_offline(phba);
 	/* release interrupt for possible resource change */
 	lpfc_sli4_disable_intr(phba);
-	lpfc_sli_brdrestart(phba);
+	rc = lpfc_sli_brdrestart(phba);
+	if (rc) {
+		lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
+				"6309 Failed to restart board\n");
+		return rc;
+	}
 	/* request and enable interrupt */
 	intr_mode = lpfc_sli4_enable_intr(phba, phba->intr_mode);
 	if (intr_mode == LPFC_INTR_ERROR) {

drivers/scsi/lpfc/lpfc_sli.c

@@ -4687,6 +4687,8 @@ lpfc_sli_brdrestart_s4(struct lpfc_hba *phba)
 	hba_aer_enabled = phba->hba_flag & HBA_AER_ENABLED;
 
 	rc = lpfc_sli4_brdreset(phba);
+	if (rc)
+		return rc;
 
 	spin_lock_irq(&phba->hbalock);
 	phba->pport->stopped = 0;