mptcp: dismiss __mptcp_rmem()

After the RX path refactor, it become a wrapper for sk_rmem_alloc
access, with a slightly misleading name. Just drop it.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-6-4a47d90d7998@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/protocol.c

@@ -496,7 +496,7 @@ static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied)
 	bool cleanup, rx_empty;
 
 	cleanup = (space > 0) && (space >= (old_space << 1)) && copied;
-	rx_empty = !__mptcp_rmem(sk) && copied;
+	rx_empty = !sk_rmem_alloc_get(sk) && copied;
 
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
@@ -645,7 +645,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		WRITE_ONCE(tp->copied_seq, seq);
 		more_data_avail = mptcp_subflow_data_available(ssk);
 
-		if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) {
+		if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf) {
 			done = true;
 			break;
 		}
@@ -782,7 +782,7 @@ static void __mptcp_data_ready(struct sock *sk, struct sock *ssk)
 	__mptcp_rcvbuf_update(sk, ssk);
 
 	/* over limit? can't append more skbs to msk, Also, no need to wake-up*/
-	if (__mptcp_rmem(sk) > sk->sk_rcvbuf)
+	if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
 		return;
 
 	/* Wake-up the reader only for in-sequence data */
@@ -2049,7 +2049,7 @@ static bool __mptcp_move_skbs(struct sock *sk)
 		mptcp_for_each_subflow(msk, subflow)
 			__mptcp_rcvbuf_update(sk, subflow->tcp_sock);
 
-	if (__mptcp_rmem(sk) > sk->sk_rcvbuf)
+	if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
 		return false;
 
 	do {

net/mptcp/protocol.h

@@ -380,14 +380,6 @@ static inline void msk_owned_by_me(const struct mptcp_sock *msk)
 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
 #endif
 
-/* the msk socket don't use the backlog, also account for the bulk
- * free memory
- */
-static inline int __mptcp_rmem(const struct sock *sk)
-{
-	return atomic_read(&sk->sk_rmem_alloc);
-}
-
 static inline int mptcp_win_from_space(const struct sock *sk, int space)
 {
 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
@@ -400,7 +392,8 @@ static inline int mptcp_space_from_win(const struct sock *sk, int win)
 
 static inline int __mptcp_space(const struct sock *sk)
 {
-	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
+	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) -
+				    sk_rmem_alloc_get(sk));
 }
 
 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)