From: Michael S. Tsirkin <mst@redhat.com>
Date: Mon, 12 Jan 2015 14:23:37 +0000 (+0200)
Subject: virtio/balloon: verify device has config space
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=2d9becc1e0c6f86e222e1955e39302d304ad274b;p=openwrt%2Fstaging%2Fblogic.git

virtio/balloon: verify device has config space

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/balloon needs config space access so make it
fail gracefully if not there.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 50c5f42d7a9f..3176ea4028a8 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -466,6 +466,12 @@ static int virtballoon_probe(struct virtio_device *vdev)
 	struct virtio_balloon *vb;
 	int err;
 
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
 	vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL);
 	if (!vb) {
 		err = -ENOMEM;