mpls: Drop RTNL for RTM_NEWROUTE, RTM_DELROUTE, and RTM_GETROUTE.

RTM_NEWROUTE looks up dev under RCU (ip_route_output(),
ipv6_stub->ipv6_dst_lookup_flow(), netdev_get_by_index()),
and each neighbour holds the refcnt of its dev.

Also, net->mpls.platform_label is protected by a dedicated
per-netns mutex.

Now, no MPLS code depends on RTNL.

Let's drop RTNL for RTM_NEWROUTE, RTM_DELROUTE, and RTM_GETROUTE.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20251029173344.2934622-14-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index d0d047dd2245f6ab7dccd8907b6b1c1a431c03ad..580aac112dd219d0cc08961ed802b713da40f115 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -2803,10 +2803,12 @@ static struct rtnl_af_ops mpls_af_ops __read_mostly = {
 };
 
 static const struct rtnl_msg_handler mpls_rtnl_msg_handlers[] __initdata_or_module = {
-       {THIS_MODULE, PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, 0},
-       {THIS_MODULE, PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, 0},
+       {THIS_MODULE, PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL,
+        RTNL_FLAG_DOIT_UNLOCKED},
+       {THIS_MODULE, PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL,
+        RTNL_FLAG_DOIT_UNLOCKED},
        {THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes,
-        RTNL_FLAG_DUMP_UNLOCKED},
+        RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
        {THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
         mpls_netconf_get_devconf, mpls_netconf_dump_devconf,
         RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},