[PATCH v3] virtio: reject shm region if length is zero

[Sami Uddin sami.md.ko@gmail.com]

From: Sami Uddin <sami.md.ko@gmail.com>

Prevent usage of shared memory regions where the length is zero,
as such configurations are not valid and may lead to unexpected behavior.

Signed-off-by: Sami Uddin <sami.md.ko@gmail.com>
---
v3:
- Use idiomatic 'if (!region->len)' as suggested by reviewer
v2:
- Fixed coding style issue: added space after 'if' statement

 include/linux/virtio_config.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 169c7d367fac..b3e1d30c765b 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -329,6 +329,8 @@ static inline
 bool virtio_get_shm_region(struct virtio_device *vdev,
 			   struct virtio_shm_region *region, u8 id)
 {
+	if (!region->len)
+		return false;
 	if (!vdev->config->get_shm_region)
 		return false;
 	return vdev->config->get_shm_region(vdev, region, id);
-- 
2.34.1