scsi: qla2xxx: Fix stale mem access on driver unload

On driver unload, 'remove_one' thread was allowed to advance, while session
cleanup still lag behind.  This patch ensures session deletion will finish
before remove_one can advance.

Link: https://lore.kernel.org/r/20190912180918.6436-4-hmadhani@marvell.comSigned-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_os.c

@@ -1118,6 +1118,7 @@ qla2x00_wait_for_sess_deletion(scsi_qla_host_t *vha)
 	qla2x00_mark_all_devices_lost(vha, 0);
 
 	wait_event_timeout(vha->fcport_waitQ, test_fcport_count(vha), 10*HZ);
+	flush_workqueue(vha->hw->wq);
 }
 
 /*

drivers/scsi/qla2xxx/qla_target.c

@@ -953,7 +953,7 @@ void qlt_free_session_done(struct work_struct *work)
 	struct qla_hw_data *ha = vha->hw;
 	unsigned long flags;
 	bool logout_started = false;
-	scsi_qla_host_t *base_vha;
+	scsi_qla_host_t *base_vha = pci_get_drvdata(ha->pdev);
 	struct qlt_plogi_ack_t *own =
 		sess->plogi_link[QLT_PLOGI_LINK_SAME_WWN];
 
@@ -1105,6 +1105,7 @@ void qlt_free_session_done(struct work_struct *work)
 	}
 
 	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
+	sess->free_pending = 0;
 
 	ql_dbg(ql_dbg_tgt_mgt, vha, 0xf001,
 	    "Unregistration of sess %p %8phC finished fcp_cnt %d\n",
@@ -1113,17 +1114,8 @@ void qlt_free_session_done(struct work_struct *work)
 	if (tgt && (tgt->sess_count == 0))
 		wake_up_all(&tgt->waitQ);
 
-	if (vha->fcport_count == 0)
-		wake_up_all(&vha->fcport_waitQ);
-
-	base_vha = pci_get_drvdata(ha->pdev);
-
-	sess->free_pending = 0;
-
-	if (test_bit(PFLG_DRIVER_REMOVING, &base_vha->pci_flags))
-		return;
-
-	if ((!tgt || !tgt->tgt_stop) && !LOOP_TRANSITION(vha)) {
+	if (!test_bit(PFLG_DRIVER_REMOVING, &base_vha->pci_flags) &&
+	    (!tgt || !tgt->tgt_stop) && !LOOP_TRANSITION(vha)) {
 		switch (vha->host->active_mode) {
 		case MODE_INITIATOR:
 		case MODE_DUAL:
@@ -1136,6 +1128,9 @@ void qlt_free_session_done(struct work_struct *work)
 			break;
 		}
 	}
+
+	if (vha->fcport_count == 0)
+		wake_up_all(&vha->fcport_waitQ);
 }
 
 /* ha->tgt.sess_lock supposed to be held on entry */
@@ -1165,7 +1160,7 @@ void qlt_unreg_sess(struct fc_port *sess)
 	sess->last_login_gen = sess->login_gen;
 
 	INIT_WORK(&sess->free_work, qlt_free_session_done);
-	schedule_work(&sess->free_work);
+	queue_work(sess->vha->hw->wq, &sess->free_work);
 }
 EXPORT_SYMBOL(qlt_unreg_sess);