IB/iser: Add asynchronous event handler

Add handler to handle events such as port up and down.  This is useful
when testing high-availability schemes such as multi-pathing.
Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/iser/iscsi_iser.h

@@ -232,6 +232,7 @@ struct iser_device {
 	struct ib_cq	             *tx_cq;
 	struct ib_mr	             *mr;
 	struct tasklet_struct	     cq_tasklet;
+	struct ib_event_handler      event_handler;
 	struct list_head             ig_list; /* entry in ig devices list */
 	int                          refcount;
 };

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -54,6 +54,13 @@ static void iser_qp_event_callback(struct ib_event *cause, void *context)
 	iser_err("got qp event %d\n",cause->event);
 }
 
+static void iser_event_handler(struct ib_event_handler *handler,
+				struct ib_event *event)
+{
+	iser_err("async event %d on device %s port %d\n", event->event,
+		event->device->name, event->element.port_num);
+}
+
 /**
  * iser_create_device_ib_res - creates Protection Domain (PD), Completion
  * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
@@ -96,8 +103,15 @@ static int iser_create_device_ib_res(struct iser_device *device)
 	if (IS_ERR(device->mr))
 		goto dma_mr_err;
 
+	INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
+				iser_event_handler);
+	if (ib_register_event_handler(&device->event_handler))
+		goto handler_err;
+
 	return 0;
 
+handler_err:
+	ib_dereg_mr(device->mr);
 dma_mr_err:
 	tasklet_kill(&device->cq_tasklet);
 cq_arm_err:
@@ -120,7 +134,7 @@ static void iser_free_device_ib_res(struct iser_device *device)
 	BUG_ON(device->mr == NULL);
 
 	tasklet_kill(&device->cq_tasklet);
-
+	(void)ib_unregister_event_handler(&device->event_handler);
 	(void)ib_dereg_mr(device->mr);
 	(void)ib_destroy_cq(device->tx_cq);
 	(void)ib_destroy_cq(device->rx_cq);