[PATCH net 2/2] mptcp: revert "mptcp: provide subflow aware release function"

[Paolo Abeni]

This change reverts commit ad98dd37051e ("mptcp: provide subflow aware
release function"). The latter introduced a deadlock spotted by
syzkaller and is not needed anymore after the previous commit.

Fixes: ad98dd37051e ("mptcp: provide subflow aware release function")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
 net/mptcp/protocol.c | 55 ++------------------------------------------
 1 file changed, 2 insertions(+), 53 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e06cea0a3c54..4bde960e19dc 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -11,7 +11,6 @@
 #include <linux/netdevice.h>
 #include <linux/sched/signal.h>
 #include <linux/atomic.h>
-#include <linux/igmp.h>
 #include <net/sock.h>
 #include <net/inet_common.h>
 #include <net/inet_hashtables.h>
@@ -20,7 +19,6 @@
 #include <net/tcp_states.h>
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 #include <net/transp_v6.h>
-#include <net/addrconf.h>
 #endif
 #include <net/mptcp.h>
 #include <net/xfrm.h>
@@ -3464,34 +3462,10 @@ static __poll_t mptcp_poll(struct file *file, struct 
socket *sock,
        return mask;
 }
 
-static int mptcp_release(struct socket *sock)
-{
-       struct mptcp_subflow_context *subflow;
-       struct sock *sk = sock->sk;
-       struct mptcp_sock *msk;
-
-       if (!sk)
-               return 0;
-
-       lock_sock(sk);
-
-       msk = mptcp_sk(sk);
-
-       mptcp_for_each_subflow(msk, subflow) {
-               struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-
-               ip_mc_drop_socket(ssk);
-       }
-
-       release_sock(sk);
-
-       return inet_release(sock);
-}
-
 static const struct proto_ops mptcp_stream_ops = {
        .family            = PF_INET,
        .owner             = THIS_MODULE,
-       .release           = mptcp_release,
+       .release           = inet_release,
        .bind              = mptcp_bind,
        .connect           = mptcp_stream_connect,
        .socketpair        = sock_no_socketpair,
@@ -3583,35 +3557,10 @@ void __init mptcp_proto_init(void)
 }
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
-static int mptcp6_release(struct socket *sock)
-{
-       struct mptcp_subflow_context *subflow;
-       struct mptcp_sock *msk;
-       struct sock *sk = sock->sk;
-
-       if (!sk)
-               return 0;
-
-       lock_sock(sk);
-
-       msk = mptcp_sk(sk);
-
-       mptcp_for_each_subflow(msk, subflow) {
-               struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-
-               ip_mc_drop_socket(ssk);
-               ipv6_sock_mc_close(ssk);
-               ipv6_sock_ac_close(ssk);
-       }
-
-       release_sock(sk);
-       return inet6_release(sock);
-}
-
 static const struct proto_ops mptcp_v6_stream_ops = {
        .family            = PF_INET6,
        .owner             = THIS_MODULE,
-       .release           = mptcp6_release,
+       .release           = inet6_release,
        .bind              = mptcp_bind,
        .connect           = mptcp_stream_connect,
        .socketpair        = sock_no_socketpair,
-- 
2.26.2