virtio_ring: Fix error reporting in virtqueue_resize

JIRA: https://issues.redhat.com/browse/RHEL-84409

commit 45ebc7e
Author: Laurent Vivier <lvivier@redhat.com>
Date:   Wed May 21 11:22:34 2025 +0200

    virtio_ring: Fix error reporting in virtqueue_resize

    The virtqueue_resize() function was not correctly propagating error codes
    from its internal resize helper functions, specifically
    virtqueue_resize_packet() and virtqueue_resize_split(). If these helpers
    returned an error, but the subsequent call to virtqueue_enable_after_reset()
    succeeded, the original error from the resize operation would be masked.
    Consequently, virtqueue_resize() could incorrectly report success to its
    caller despite an underlying resize failure.

    This change restores the original code behavior:

           if (vdev->config->enable_vq_after_reset(_vq))
                   return -EBUSY;

           return err;

    Fix: commit ad48d53 ("virtio_ring: separate the logic of reset/enable from virtqueue_resize")
    Cc: xuanzhuo@linux.alibaba.com
    Signed-off-by: Laurent Vivier <lvivier@redhat.com>
    Acked-by: Jason Wang <jasowang@redhat.com>
    Link: https://patch.msgid.link/20250521092236.661410-2-lvivier@redhat.com
    Tested-by: Lei Yang <leiyang@redhat.com>
    Acked-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Author: vivier

drivers/virtio/virtio_ring.c

@@ -2741,7 +2741,7 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 		     void (*recycle_done)(struct virtqueue *vq))
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
-	int err;
+	int err, err_reset;
 
 	if (num > vq->vq.num_max)
 		return -E2BIG;
@@ -2763,7 +2763,11 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 	else
 		err = virtqueue_resize_split(_vq, num);
 
-	return virtqueue_enable_after_reset(_vq);
+	err_reset = virtqueue_enable_after_reset(_vq);
+	if (err_reset)
+		return err_reset;
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(virtqueue_resize);