genetlink: Build a generic netlink family module alias

Generic netlink searches for -type- formatted aliases when requesting a module to
fulfill a protocol request (i.e. net-pf-16-proto-16-type-<x>, where x is a type
value).  However generic netlink protocols have no well defined type numbers,
they have string names.  Modify genl_ctrl_getfamily to request an alias in the
format net-pf-16-proto-16-family-<x> instead, where x is a generic string, and
add a macro that builds on the previously added MODULE_ALIAS_NET_PF_PROTO_NAME
macro to allow modules to specifify those generic strings.

Note, l2tp previously hacked together an net-pf-16-proto-16-type-l2tp alias
using the MODULE_ALIAS macro, with these updates we can convert that to use the
PROTO_NAME macro.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: James Chapman <jchapman@katalix.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 8577264378fe..ddc553e76671 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -923,5 +923,4 @@ MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 MODULE_DESCRIPTION("L2TP netlink");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.0");
-MODULE_ALIAS("net-pf-" __stringify(PF_NETLINK) "-proto-" \
-             __stringify(NETLINK_GENERIC) "-type-" "l2tp");
+MODULE_ALIAS_GENL_FAMILY("l2tp");