Char: virtio_console, fix memory leak

Stanse found that in init_vqs, memory is leaked under certain
circumstanses (the fail path order is incorrect). Fix that by checking
allocations in one turn and free all of them at once if some fails
(some may be NULL, but this is OK).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/char/virtio_console.c

@@ -1547,31 +1547,16 @@ static int init_vqs(struct ports_device *portdev)
 	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
 
 	vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
-	if (!vqs) {
-		err = -ENOMEM;
-		goto fail;
-	}
 	io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
-	if (!io_callbacks) {
-		err = -ENOMEM;
-		goto free_vqs;
-	}
 	io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
-	if (!io_names) {
-		err = -ENOMEM;
-		goto free_callbacks;
-	}
 	portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
 				  GFP_KERNEL);
-	if (!portdev->in_vqs) {
-		err = -ENOMEM;
-		goto free_names;
-	}
 	portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
 				   GFP_KERNEL);
-	if (!portdev->out_vqs) {
+	if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
+			!portdev->out_vqs) {
 		err = -ENOMEM;
-		goto free_invqs;
+		goto free;
 	}
 
 	/*
@@ -1605,7 +1590,7 @@ static int init_vqs(struct ports_device *portdev)
 					      io_callbacks,
 					      (const char **)io_names);
 	if (err)
-		goto free_outvqs;
+		goto free;
 
 	j = 0;
 	portdev->in_vqs[0] = vqs[0];
@@ -1621,23 +1606,19 @@ static int init_vqs(struct ports_device *portdev)
 			portdev->out_vqs[i] = vqs[j + 1];
 		}
 	}
-	kfree(io_callbacks);
 	kfree(io_names);
+	kfree(io_callbacks);
 	kfree(vqs);
 
 	return 0;
 
-free_names:
-	kfree(io_names);
-free_callbacks:
-	kfree(io_callbacks);
-free_outvqs:
+free:
 	kfree(portdev->out_vqs);
-free_invqs:
 	kfree(portdev->in_vqs);
-free_vqs:
+	kfree(io_names);
+	kfree(io_callbacks);
 	kfree(vqs);
-fail:
+
 	return err;
 }