scsi: lpfc: Correct irq handling via locks when taking adapter offline

When taking the board offline while performing i/o, unsafe locking errors
occurred and irq level isn't properly managed.

In lpfc_sli_hba_down, spin_lock_irqsave(&phba->hbalock, flags) does not
disable softirqs raised from timer expiry.  It is possible that a softirq is
raised from the lpfc_els_retry_delay routine and recursively requests the same
phba->hbalock spinlock causing deadlock.

Address the deadlocks by creating a new port_list lock. The softirq behavior
can then be managed a level deeper into the calling sequences.
Signed-off-by: NDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc.h

@@ -964,6 +964,7 @@ struct lpfc_hba {
 	uint32_t intr_mode;
 #define LPFC_INTR_ERROR	0xFFFFFFFF
 	struct list_head port_list;
+	spinlock_t port_list_lock;	/* lock for port_list mutations */
 	struct lpfc_vport *pport;	/* physical lpfc_vport pointer */
 	uint16_t max_vpi;		/* Maximum virtual nports */
 #define LPFC_MAX_VPI 0xFFFF		/* Max number of VPI supported */

drivers/scsi/lpfc/lpfc_ct.c

@@ -445,14 +445,14 @@ lpfc_find_vport_by_did(struct lpfc_hba *phba, uint32_t did) {
 	struct lpfc_vport *vport_curr;
 	unsigned long flags;
 
-	spin_lock_irqsave(&phba->hbalock, flags);
+	spin_lock_irqsave(&phba->port_list_lock, flags);
 	list_for_each_entry(vport_curr, &phba->port_list, listentry) {
 		if ((vport_curr->fc_myDID) && (vport_curr->fc_myDID == did)) {
-			spin_unlock_irqrestore(&phba->hbalock, flags);
+			spin_unlock_irqrestore(&phba->port_list_lock, flags);
 			return vport_curr;
 		}
 	}
-	spin_unlock_irqrestore(&phba->hbalock, flags);
+	spin_unlock_irqrestore(&phba->port_list_lock, flags);
 	return NULL;
 }
 

drivers/scsi/lpfc/lpfc_els.c

@@ -7673,8 +7673,11 @@ void
 lpfc_els_flush_all_cmd(struct lpfc_hba  *phba)
 {
 	struct lpfc_vport *vport;
+
+	spin_lock_irq(&phba->port_list_lock);
 	list_for_each_entry(vport, &phba->port_list, listentry)
 		lpfc_els_flush_cmd(vport);
+	spin_unlock_irq(&phba->port_list_lock);
 
 	return;
 }

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -5938,14 +5938,14 @@ lpfc_find_vport_by_vpid(struct lpfc_hba *phba, uint16_t vpi)
 		}
 	}
 
-	spin_lock_irqsave(&phba->hbalock, flags);
+	spin_lock_irqsave(&phba->port_list_lock, flags);
 	list_for_each_entry(vport, &phba->port_list, listentry) {
 		if (vport->vpi == i) {
-			spin_unlock_irqrestore(&phba->hbalock, flags);
+			spin_unlock_irqrestore(&phba->port_list_lock, flags);
 			return vport;
 		}
 	}
-	spin_unlock_irqrestore(&phba->hbalock, flags);
+	spin_unlock_irqrestore(&phba->port_list_lock, flags);
 	return NULL;
 }
 

drivers/scsi/lpfc/lpfc_init.c

@@ -3988,9 +3988,9 @@ lpfc_create_port(struct lpfc_hba *phba, int instance, struct device *dev)
 	if (error)
 		goto out_put_shost;
 
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_add_tail(&vport->listentry, &phba->port_list);
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 	return vport;
 
 out_put_shost:
@@ -4016,9 +4016,9 @@ destroy_port(struct lpfc_vport *vport)
 	fc_remove_host(shost);
 	scsi_remove_host(shost);
 
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_del_init(&vport->listentry);
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 
 	lpfc_cleanup(vport);
 	return;
@@ -5621,7 +5621,10 @@ lpfc_setup_driver_resource_phase1(struct lpfc_hba *phba)
 	/* Initialize ndlp management spinlock */
 	spin_lock_init(&phba->ndlp_lock);
 
+	/* Initialize port_list spinlock */
+	spin_lock_init(&phba->port_list_lock);
 	INIT_LIST_HEAD(&phba->port_list);
+
 	INIT_LIST_HEAD(&phba->work_list);
 	init_waitqueue_head(&phba->wait_4_mlo_m_q);
 
@@ -10985,9 +10988,9 @@ lpfc_pci_remove_one_s3(struct pci_dev *pdev)
 	kfree(phba->vpi_ids);
 
 	lpfc_stop_hba_timers(phba);
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_del_init(&vport->listentry);
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 
 	lpfc_debugfs_terminate(vport);
 
@@ -11797,9 +11800,9 @@ lpfc_pci_remove_one_s4(struct pci_dev *pdev)
 	lpfc_sli4_hba_unset(phba);
 
 	lpfc_stop_hba_timers(phba);
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_del_init(&vport->listentry);
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 
 	/* Perform scsi free before driver resource_unset since scsi
 	 * buffers are released to their corresponding pools here.

drivers/scsi/lpfc/lpfc_sli.c

@@ -10273,8 +10273,12 @@ lpfc_sli_mbox_sys_flush(struct lpfc_hba *phba)
 	LPFC_MBOXQ_t *pmb;
 	unsigned long iflag;
 
+	/* Disable softirqs, including timers from obtaining phba->hbalock */
+	local_bh_disable();
+
 	/* Flush all the mailbox commands in the mbox system */
 	spin_lock_irqsave(&phba->hbalock, iflag);
+
 	/* The pending mailbox command queue */
 	list_splice_init(&phba->sli.mboxq, &completions);
 	/* The outstanding active mailbox command */
@@ -10287,6 +10291,9 @@ lpfc_sli_mbox_sys_flush(struct lpfc_hba *phba)
 	list_splice_init(&phba->sli.mboxq_cmpl, &completions);
 	spin_unlock_irqrestore(&phba->hbalock, iflag);
 
+	/* Enable softirqs again, done with phba->hbalock */
+	local_bh_enable();
+
 	/* Return all flushed mailbox commands with MBX_NOT_FINISHED status */
 	while (!list_empty(&completions)) {
 		list_remove_head(&completions, pmb, LPFC_MBOXQ_t, list);
@@ -10426,6 +10433,9 @@ lpfc_sli_hba_down(struct lpfc_hba *phba)
 
 	lpfc_hba_down_prep(phba);
 
+	/* Disable softirqs, including timers from obtaining phba->hbalock */
+	local_bh_disable();
+
 	lpfc_fabric_abort_hba(phba);
 
 	spin_lock_irqsave(&phba->hbalock, flags);
@@ -10479,6 +10489,9 @@ lpfc_sli_hba_down(struct lpfc_hba *phba)
 		kfree(buf_ptr);
 	}
 
+	/* Enable softirqs again, done with phba->hbalock */
+	local_bh_enable();
+
 	/* Return any active mbox cmds */
 	del_timer_sync(&psli->mbox_tmo);
 
@@ -11782,6 +11795,9 @@ lpfc_sli_mbox_sys_shutdown(struct lpfc_hba *phba, int mbx_action)
 	}
 	timeout = msecs_to_jiffies(LPFC_MBOX_TMO * 1000) + jiffies;
 
+	/* Disable softirqs, including timers from obtaining phba->hbalock */
+	local_bh_disable();
+
 	spin_lock_irq(&phba->hbalock);
 	psli->sli_flag |= LPFC_SLI_ASYNC_MBX_BLK;
 
@@ -11795,6 +11811,9 @@ lpfc_sli_mbox_sys_shutdown(struct lpfc_hba *phba, int mbx_action)
 						1000) + jiffies;
 		spin_unlock_irq(&phba->hbalock);
 
+		/* Enable softirqs again, done with phba->hbalock */
+		local_bh_enable();
+
 		while (phba->sli.mbox_active) {
 			/* Check active mailbox complete status every 2ms */
 			msleep(2);
@@ -11804,9 +11823,13 @@ lpfc_sli_mbox_sys_shutdown(struct lpfc_hba *phba, int mbx_action)
 				 */
 				break;
 		}
-	} else
+	} else {
 		spin_unlock_irq(&phba->hbalock);
 
+		/* Enable softirqs again, done with phba->hbalock */
+		local_bh_enable();
+	}
+
 	lpfc_sli_mbox_sys_flush(phba);
 }
 

drivers/scsi/lpfc/lpfc_vport.c

@@ -207,7 +207,7 @@ lpfc_unique_wwpn(struct lpfc_hba *phba, struct lpfc_vport *new_vport)
 	struct lpfc_vport *vport;
 	unsigned long flags;
 
-	spin_lock_irqsave(&phba->hbalock, flags);
+	spin_lock_irqsave(&phba->port_list_lock, flags);
 	list_for_each_entry(vport, &phba->port_list, listentry) {
 		if (vport == new_vport)
 			continue;
@@ -215,11 +215,11 @@ lpfc_unique_wwpn(struct lpfc_hba *phba, struct lpfc_vport *new_vport)
 		if (memcmp(&vport->fc_sparam.portName,
 			   &new_vport->fc_sparam.portName,
 			   sizeof(struct lpfc_name)) == 0) {
-			spin_unlock_irqrestore(&phba->hbalock, flags);
+			spin_unlock_irqrestore(&phba->port_list_lock, flags);
 			return 0;
 		}
 	}
-	spin_unlock_irqrestore(&phba->hbalock, flags);
+	spin_unlock_irqrestore(&phba->port_list_lock, flags);
 	return 1;
 }
 
@@ -825,9 +825,9 @@ lpfc_vport_delete(struct fc_vport *fc_vport)
 
 	lpfc_free_vpi(phba, vport->vpi);
 	vport->work_port_events = 0;
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_del_init(&vport->listentry);
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 	lpfc_printf_vlog(vport, KERN_ERR, LOG_VPORT,
 			 "1828 Vport Deleted.\n");
 	scsi_host_put(shost);
@@ -844,7 +844,7 @@ lpfc_create_vport_work_array(struct lpfc_hba *phba)
 			 GFP_KERNEL);
 	if (vports == NULL)
 		return NULL;
-	spin_lock_irq(&phba->hbalock);
+	spin_lock_irq(&phba->port_list_lock);
 	list_for_each_entry(port_iterator, &phba->port_list, listentry) {
 		if (port_iterator->load_flag & FC_UNLOADING)
 			continue;
@@ -856,7 +856,7 @@ lpfc_create_vport_work_array(struct lpfc_hba *phba)
 		}
 		vports[index++] = port_iterator;
 	}
-	spin_unlock_irq(&phba->hbalock);
+	spin_unlock_irq(&phba->port_list_lock);
 	return vports;
 }