[PATCH] vhost-user: fix shared object lookup handler logic

[Albert Esteve <aesteve@redhat.com>]

Fix vhost_user_backend_handle_shared_object_lookup() logic to handle
the error path the same way as other handlers do. The main
difference between them is that shared_object_lookup handler
sends the reply from within the handler itself.

What vhost_user_backend_handle_shared_object_lookup() returns, depends
on whether vhost_user_backend_send_dmabuf_fd() succeded or not to send
a reply. Any check that results in an error before that only
determines the return value in the response. However, when an error
in sending the response within the handler occurs, we want to jump
to err and close the backend channel to be consistent with other message
types. On the other hand, when the response succeds then the
VHOST_USER_NEED_REPLY_MASK flag is unset and the reply in backend_read
is skipped, going directly to the fdcleanup.

Fixes: 160947666276c5b7f6bca4d746bcac2966635d79
Signed-off-by: Albert Esteve <aesteve@redhat.com>
---
 hw/virtio/vhost-user.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 36c9c2e04d..163c3d8ca5 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1833,8 +1833,11 @@ static gboolean backend_read(QIOChannel *ioc, GIOCondition condition,
                                                              &payload.object);
         break;
     case VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP:
-        ret = vhost_user_backend_handle_shared_object_lookup(dev->opaque, ioc,
-                                                             &hdr, &payload);
+        /* Handler manages its own response, check error and close connection */
+        if (vhost_user_backend_handle_shared_object_lookup(dev->opaque, ioc,
+                                                           &hdr, &payload) < 0) {
+            goto err;
+        }
         break;
     default:
         error_report("Received unexpected msg type: %d.", hdr.request);
-- 
2.49.0