From 7754f53e944122fa95ef36039d3a5009910ce6fc Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Mon, 12 Jan 2015 16:23:37 +0200
Subject: virtio/9p: verify device has config space

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/9p 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>
---
 net/9p/trans_virtio.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'net/9p')

diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index daa749c8b3fb..d8e376a5f0f1 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -524,6 +524,12 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 	int err;
 	struct virtio_chan *chan;
 
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
 	chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
 	if (!chan) {
 		pr_err("Failed to allocate virtio 9P channel\n");
-- 
cgit