Commit d51bbff2 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
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bpf: net: Avoid do_tcp_getsockopt() taking sk lock when called from bpf 



Similar to the earlier commit that changed sk_setsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking
lock when called from bpf.  This patch also changes do_tcp_getsockopt()
to use sockopt_{lock,release}_sock() such that a latter patch can
make bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt().

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002821.2889765-1-kafai@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 34704ef0

net/ipv4/tcp.c

+9 −9
Original line number Diff line number Diff line
@@ -4265,30 +4265,30 @@ static int do_tcp_getsockopt(struct sock *sk, int level, 
		if (copy_from_sockptr(&len, optlen, sizeof(int)))

			return -EFAULT;



		lock_sock(sk);

		sockopt_lock_sock(sk);

		if (tp->saved_syn) {

			if (len < tcp_saved_syn_len(tp->saved_syn)) {

				len = tcp_saved_syn_len(tp->saved_syn);

				if (copy_to_sockptr(optlen, &len, sizeof(int))) {

					release_sock(sk);

					sockopt_release_sock(sk);

					return -EFAULT;

				}

				release_sock(sk);

				sockopt_release_sock(sk);

				return -EINVAL;

			}

			len = tcp_saved_syn_len(tp->saved_syn);

			if (copy_to_sockptr(optlen, &len, sizeof(int))) {

				release_sock(sk);

				sockopt_release_sock(sk);

				return -EFAULT;

			}

			if (copy_to_sockptr(optval, tp->saved_syn->data, len)) {

				release_sock(sk);

				sockopt_release_sock(sk);

				return -EFAULT;

			}

			tcp_saved_syn_free(tp);

			release_sock(sk);

			sockopt_release_sock(sk);

		} else {

			release_sock(sk);

			sockopt_release_sock(sk);

			len = 0;

			if (copy_to_sockptr(optlen, &len, sizeof(int)))

				return -EFAULT;
@@ -4321,11 +4321,11 @@ static int do_tcp_getsockopt(struct sock *sk, int level, 
			return -EINVAL;

		if (zc.msg_flags &  ~(TCP_VALID_ZC_MSG_FLAGS))

			return -EINVAL;

		lock_sock(sk);

		sockopt_lock_sock(sk);

		err = tcp_zerocopy_receive(sk, &zc, &tss);

		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,

							  &zc, &len, err);

		release_sock(sk);

		sockopt_release_sock(sk);

		if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))

			goto zerocopy_rcv_cmsg;

		switch (len) {