The RDMA CM will select a source device and address by consulting
the routing table if no source address is passed into
rdma_resolve_address(). Userspace will ask for this by passing an
all-zero source address in the RESOLVE_IP command. Unfortunately
the new check for non-zero address size rejects this with EINVAL,
which breaks valid userspace applications.
Fix this by explicitly allowing a zero address family for the source.
Fixes: 2975d5de6428 ("RDMA/ucma: Check AF family prior resolving address") Cc: <stable@vger.kernel.org> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Doug Ledford <dledford@redhat.com>