From: Michael S. Tsirkin <mst@redhat.com>
Date: Mon, 12 Jan 2015 14:23:37 +0000 (+0200)
Subject: virtio/blk: verify device has config space
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=a4379fd841cc1af60ef495b8e5598b1f7327ec0c;p=deliverable%2Flinux.git

virtio/blk: verify device has config space

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/blk 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/block/virtio_blk.c b/drivers/block/virtio_blk.c
index cdfbd21e3597..b72c11a10f40 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -575,6 +575,12 @@ static int virtblk_probe(struct virtio_device *vdev)
 	u16 min_io_size;
 	u8 physical_block_exp, alignment_offset;
 
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
 	err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
 			     GFP_KERNEL);
 	if (err < 0)