virtio_balloon: warn on failed buffer add in stats_handle_request()

Like tell_host(), stats_handle_request() ignores the return value of
virtqueue_add_outbuf() and kicks the queue regardless. The same "we
should always be able to add one buffer to an empty queue" assumption
does not hold once the virtqueue has been broken (e.g. on device
shutdown), where the add fails with -EIO. Unlike tell_host() it does
not wait_event() afterwards so it cannot hang, but it still kicks a
queue with nothing queued.

Warn and bail out on failure, mirroring tell_host() and
virtballoon_free_page_report().

Suggested-by: David Hildenbrand <david@kernel.org>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260624154001.2733242-1-den@openvz.org>

0 files changed, 0 insertions, 0 deletions