rtnetlink: do not use RTNL in rtnl_af_register() and rtnl_af_unregister()

rtnl_af_lookup() does not rely on RTNL anymoe, remove the stale
ASSERT_RTNL().

Add a private spinlock (rtnl_af_ops_lock) to protect rtnl_af_ops
list instead of using RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260521174038.204481-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 3d40ebe035b37ae0f38fb81f918eb76742371ef1..5e461c752df122e1afed8fdc82206a8d7e8f90c7 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -750,13 +750,12 @@ static size_t rtnl_link_get_size(const struct net_device *dev)
 }
 
 static LIST_HEAD(rtnl_af_ops);
+static DEFINE_SPINLOCK(rtnl_af_ops_lock);
 
 static struct rtnl_af_ops *rtnl_af_lookup(const int family, int *srcu_index)
 {
        struct rtnl_af_ops *ops;
 
-       ASSERT_RTNL();
-
        rcu_read_lock();
 
        list_for_each_entry_rcu(ops, &rtnl_af_ops, list) {
@@ -791,9 +790,9 @@ int rtnl_af_register(struct rtnl_af_ops *ops)
        if (err)
                return err;
 
-       rtnl_lock();
+       spin_lock(&rtnl_af_ops_lock);
        list_add_tail_rcu(&ops->list, &rtnl_af_ops);
-       rtnl_unlock();
+       spin_unlock(&rtnl_af_ops_lock);
 
        return 0;
 }
@@ -805,9 +804,9 @@ EXPORT_SYMBOL_GPL(rtnl_af_register);
  */
 void rtnl_af_unregister(struct rtnl_af_ops *ops)
 {
-       rtnl_lock();
+       spin_lock(&rtnl_af_ops_lock);
        list_del_rcu(&ops->list);
-       rtnl_unlock();
+       spin_unlock(&rtnl_af_ops_lock);
 
        synchronize_rcu();
        synchronize_srcu(&ops->srcu);