In commit f360d88a2efd, we advertise blocking multicast loopback to both kernel and userspace consumers, but don't allow kernel consumers (e.g IPoIB) to use it with their UD QPs. Fix that. Fixes: f360d88a2efd ("IB/mlx5: Add block multicast loopback support") Reported-by: Haggai Eran <haggaie@mellanox.com> Signed-off-by: Eli Cohen <eli@mellanox.com> Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>