From: Geliang Tang <tanggeliang@kylinos.cn>

bpf_core_cast() can be used in mptcp_subflow bpf_iter selftests to get the
msk, instead of using bpf_skc_to_mptcp_sock(). No need to add this patch
anymore, revert it.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h |  4 ++--
 net/core/filter.c   |  2 +-
 net/mptcp/bpf.c     | 10 ++--------
 3 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 72d6e6597add..2c85ca92bb1c 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -323,9 +323,9 @@ static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
 #endif
 
 #if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
-struct mptcp_sock *bpf_mptcp_sock_from_sock(struct sock *sk);
+struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
 #else
-static inline struct mptcp_sock *bpf_mptcp_sock_from_sock(struct sock *sk) { return NULL; }
+static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
 #endif
 
 #if !IS_ENABLED(CONFIG_MPTCP)
diff --git a/net/core/filter.c b/net/core/filter.c
index fc094e8d53d3..2ec162dd83c4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -11843,7 +11843,7 @@ const struct bpf_func_proto bpf_skc_to_unix_sock_proto = {
 BPF_CALL_1(bpf_skc_to_mptcp_sock, struct sock *, sk)
 {
 	BTF_TYPE_EMIT(struct mptcp_sock);
-	return (unsigned long)bpf_mptcp_sock_from_sock(sk);
+	return (unsigned long)bpf_mptcp_sock_from_subflow(sk);
 }
 
 const struct bpf_func_proto bpf_skc_to_mptcp_sock_proto = {
diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
index be222fa5f308..7e9d9c9a04cf 100644
--- a/net/mptcp/bpf.c
+++ b/net/mptcp/bpf.c
@@ -195,15 +195,9 @@ static struct bpf_struct_ops bpf_mptcp_sched_ops = {
 };
 #endif /* CONFIG_BPF_JIT */
 
-struct mptcp_sock *bpf_mptcp_sock_from_sock(struct sock *sk)
+struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk)
 {
-	if (unlikely(!sk || !sk_fullsock(sk)))
-		return NULL;
-
-	if (sk->sk_protocol == IPPROTO_MPTCP)
-		return mptcp_sk(sk);
-
-	if (sk->sk_protocol == IPPROTO_TCP && sk_is_mptcp(sk))
+	if (sk && sk_fullsock(sk) && sk->sk_protocol == IPPROTO_TCP && sk_is_mptcp(sk))
 		return mptcp_sk(mptcp_subflow_ctx(sk)->conn);
 
 	return NULL;
-- 
2.43.0