Commit a4725d0d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

inet: lockless getsockopt(IP_OPTIONS) 



inet->inet_opt being RCU protected, we can use RCU instead
of locking the socket.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e08d0b3d

net/ipv4/ip_sockglue.c

+10 −10
Original line number Diff line number Diff line
@@ -1591,27 +1591,20 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname, 
	case IP_TOS:

		val = READ_ONCE(inet->tos);

		goto copyval;

	}



	if (needs_rtnl)

		rtnl_lock();

	sockopt_lock_sock(sk);



	switch (optname) {

	case IP_OPTIONS:

	{

		unsigned char optbuf[sizeof(struct ip_options)+40];

		struct ip_options *opt = (struct ip_options *)optbuf;

		struct ip_options_rcu *inet_opt;



		inet_opt = rcu_dereference_protected(inet->inet_opt,

						     lockdep_sock_is_held(sk));

		rcu_read_lock();

		inet_opt = rcu_dereference(inet->inet_opt);

		opt->optlen = 0;

		if (inet_opt)

			memcpy(optbuf, &inet_opt->opt,

			       sizeof(struct ip_options) +

			       inet_opt->opt.optlen);

		sockopt_release_sock(sk);

		rcu_read_unlock();



		if (opt->optlen == 0) {

			len = 0;
@@ -1627,6 +1620,13 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname, 
			return -EFAULT;

		return 0;

	}

	}



	if (needs_rtnl)

		rtnl_lock();

	sockopt_lock_sock(sk);



	switch (optname) {

	case IP_MTU:

	{

		struct dst_entry *dst;