From e60ea67bb60459b95a50a156296041a13e0e380e Mon Sep 17 00:00:00 2001
From: weiping zhang <zwp10758@gmail.com>
Date: Wed, 29 Nov 2017 09:23:01 +0800
Subject: [PATCH] virtio: release virtio index when fail to device_register
Git-commit: e60ea67bb60459b95a50a156296041a13e0e380e
Patch-mainline: v4.15-rc3
References: bsc#1051510

index can be reused by other virtio device.

Cc: stable@vger.kernel.org
Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/virtio/virtio.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -333,6 +333,8 @@ int register_virtio_device(struct virtio
 	/* device_register() causes the bus infrastructure to look for a
 	 * matching driver. */
 	err = device_register(&dev->dev);
+	if (err)
+		ida_simple_remove(&virtio_index_ida, dev->index);
 out:
 	if (err)
 		virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);