IB/iser: Fix list iteration bug

The iteration through the list of "iser_device"s during device
lookup/creation is broken -- it might result in an infinite loop if
more than one HCA is used with iSER.  Fix this by using
list_for_each_entry() instead of the open-coded flawed list iteration
code.
Signed-off-by: Arne Redlich <arne.redlich@xiranet.com>
Signed-off-by: Erez Zilber <erezz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -237,23 +237,19 @@ static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
 static
 struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
 {
-	struct list_head    *p_list;
-	struct iser_device  *device = NULL;
+	struct iser_device *device;
 
 	mutex_lock(&ig.device_list_mutex);
 
-	p_list = ig.device_list.next;
-	while (p_list != &ig.device_list) {
-		device = list_entry(p_list, struct iser_device, ig_list);
+	list_for_each_entry(device, &ig.device_list, ig_list)
 		/* find if there's a match using the node GUID */
 		if (device->ib_device->node_guid == cma_id->device->node_guid)
-			break;
-	}
+			goto out;
 
-	if (device == NULL) {
 	device = kzalloc(sizeof *device, GFP_KERNEL);
 	if (device == NULL)
 		goto out;
+
 	/* assign this device to the device */
 	device->ib_device = cma_id->device;
 	/* init the device and link it into ig device list */
@@ -263,7 +259,7 @@ struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
 		goto out;
 	}
 	list_add(&device->ig_list, &ig.device_list);
-	}
+
 out:
 	BUG_ON(device == NULL);
 	device->refcount++;