amt does not need to access struct socket itself in the fast path;
it only reads struct sock, and struct socket is only used for tunnel
setup and teardown.
Let's store struct sock directly in struct amt.
amt_dev_stop() is called as dev->netdev_ops->ndo_stop().
synchronize_net() in unregister_netdevice_many_notify() ensures
that inflight amt RX fast paths finish before amt_dev is freed.
amt no longer needs synchronize_rcu() in udp_tunnel_sock_release().
Note that amt_dev_stop() looks buggy; cancel_delayed_work_sync()
should be called after udp_tunnel_sock_release().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260502031401.3557229-13-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
65c6e06d5a