[PATCH 6.1.y] virtio: reenable config if freezing device failed

[David Hildenbrand <david@redhat.com>]

Currently, we don't reenable the config if freezing the device failed.

For example, virtio-mem currently doesn't support suspend+resume, and
trying to freeze the device will always fail. Afterwards, the device
will no longer respond to resize requests, because it won't get notified
about config changes.

Let's fix this by re-enabling the config if freezing fails.

Fixes: 22b7050a024d ("virtio: defer config changed notifications")
Cc: <stable@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240213135425.795001-1-david@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 310227f42882c52356b523e2f4e11690eebcd2ab)
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/virtio/virtio.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 828ced060742..1ef094427f29 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -489,13 +489,19 @@ EXPORT_SYMBOL_GPL(unregister_virtio_device);
 int virtio_device_freeze(struct virtio_device *dev)
 {
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+	int ret;
 
 	virtio_config_disable(dev);
 
 	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
 
-	if (drv && drv->freeze)
-		return drv->freeze(dev);
+	if (drv && drv->freeze) {
+		ret = drv->freeze(dev);
+		if (ret) {
+			virtio_config_enable(dev);
+			return ret;
+		}
+	}
 
 	return 0;
 }
-- 
2.44.0