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

net/ipv4/tcp.c

@@ -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) {