mptcp: change the mpc check helper to return a sk

After the previous patch the __mptcp_nmpc_socket helper is used
only to ensure that the MPTCP socket is a suitable status - that
is, the mptcp capable handshake is not started yet.

Change the return value to the relevant subflow sock, to finally
remove the last references to first subflow socket in the MPTCP stack.

As a bonus, we can get rid of a few local variables in different
functions.

No functional change intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 24 deletions

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 6661852f8d97..21bc46acbe38 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -292,7 +292,6 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
 				       sockptr_t optval, unsigned int optlen)
 {
 	struct sock *sk = (struct sock *)msk;
-	struct socket *ssock;
 	struct sock *ssk;
 	int ret;
 
@@ -302,13 +301,12 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
 	case SO_BINDTODEVICE:
 	case SO_BINDTOIFINDEX:
 		lock_sock(sk);
-		ssock = __mptcp_nmpc_socket(msk);
-		if (IS_ERR(ssock)) {
+		ssk = __mptcp_nmpc_sk(msk);
+		if (IS_ERR(ssk)) {
 			release_sock(sk);
-			return PTR_ERR(ssock);
+			return PTR_ERR(ssk);
 		}
 
-		ssk = msk->first;
 		ret = sk_setsockopt(ssk, SOL_SOCKET, optname, optval, optlen);
 		if (ret == 0) {
 			if (optname == SO_REUSEPORT)
@@ -392,7 +390,6 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
 {
 	struct sock *sk = (struct sock *)msk;
 	int ret = -EOPNOTSUPP;
-	struct socket *ssock;
 	struct sock *ssk;
 
 	switch (optname) {
@@ -400,13 +397,12 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
 	case IPV6_TRANSPARENT:
 	case IPV6_FREEBIND:
 		lock_sock(sk);
-		ssock = __mptcp_nmpc_socket(msk);
-		if (IS_ERR(ssock)) {
+		ssk = __mptcp_nmpc_sk(msk);
+		if (IS_ERR(ssk)) {
 			release_sock(sk);
-			return PTR_ERR(ssock);
+			return PTR_ERR(ssk);
 		}
 
-		ssk = msk->first;
 		ret = tcp_setsockopt(ssk, SOL_IPV6, optname, optval, optlen);
 		if (ret != 0) {
 			release_sock(sk);
@@ -689,7 +685,7 @@ static int mptcp_setsockopt_sol_ip_set_transparent(struct mptcp_sock *msk, int o
 {
 	struct sock *sk = (struct sock *)msk;
 	struct inet_sock *issk;
-	struct socket *ssock;
+	struct sock *ssk;
 	int err;
 
 	err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
@@ -698,13 +694,13 @@ static int mptcp_setsockopt_sol_ip_set_transparent(struct mptcp_sock *msk, int o
 
 	lock_sock(sk);
 
-	ssock = __mptcp_nmpc_socket(msk);
-	if (IS_ERR(ssock)) {
+	ssk = __mptcp_nmpc_sk(msk);
+	if (IS_ERR(ssk)) {
 		release_sock(sk);
-		return PTR_ERR(ssock);
+		return PTR_ERR(ssk);
 	}
 
-	issk = inet_sk(msk->first);
+	issk = inet_sk(ssk);
 
 	switch (optname) {
 	case IP_FREEBIND:
@@ -767,18 +763,18 @@ static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int
 					  sockptr_t optval, unsigned int optlen)
 {
 	struct sock *sk = (struct sock *)msk;
-	struct socket *sock;
+	struct sock *ssk;
 	int ret;
 
 	/* Limit to first subflow, before the connection establishment */
 	lock_sock(sk);
-	sock = __mptcp_nmpc_socket(msk);
-	if (IS_ERR(sock)) {
-		ret = PTR_ERR(sock);
+	ssk = __mptcp_nmpc_sk(msk);
+	if (IS_ERR(ssk)) {
+		ret = PTR_ERR(ssk);
 		goto unlock;
 	}
 
-	ret = tcp_setsockopt(sock->sk, level, optname, optval, optlen);
+	ret = tcp_setsockopt(ssk, level, optname, optval, optlen);
 
 unlock:
 	release_sock(sk);
@@ -868,7 +864,6 @@ static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int
 					  char __user *optval, int __user *optlen)
 {
 	struct sock *sk = (struct sock *)msk;
-	struct socket *ssock;
 	struct sock *ssk;
 	int ret;
 
@@ -879,9 +874,9 @@ static int mptcp_getsockopt_first_sf_only(struct mptcp_sock *msk, int level, int
 		goto out;
 	}
 
-	ssock = __mptcp_nmpc_socket(msk);
-	if (IS_ERR(ssock)) {
-		ret = PTR_ERR(ssock);
+	ssk = __mptcp_nmpc_sk(msk);
+	if (IS_ERR(ssk)) {
+		ret = PTR_ERR(ssk);
 		goto out;
 	}