mptcp: factor out __mptcp_close() without socket lock

Factor out __mptcp_close() from mptcp_close(). The caller of
__mptcp_close() should hold the socket lock, and cancel mptcp work when
__mptcp_close() returns true.

This function will be used in the next commit.

Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests")
Fixes: 6aeed9045071 ("mptcp: fix race on unaccepted mptcp sockets")
Cc: stable@vger.kernel.org
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Mengen Sun <mengensun@tencent.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 969b33a..f769041 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2802,13 +2802,12 @@ static void __mptcp_destroy_sock(struct sock *sk)
        sock_put(sk);
 }
 
-static void mptcp_close(struct sock *sk, long timeout)
+bool __mptcp_close(struct sock *sk, long timeout)
 {
        struct mptcp_subflow_context *subflow;
        struct mptcp_sock *msk = mptcp_sk(sk);
        bool do_cancel_work = false;
 
-       lock_sock(sk);
        sk->sk_shutdown = SHUTDOWN_MASK;
 
        if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
@@ -2850,6 +2849,17 @@ cleanup:
        } else {
                mptcp_reset_timeout(msk, 0);
        }
+
+       return do_cancel_work;
+}
+
+static void mptcp_close(struct sock *sk, long timeout)
+{
+       bool do_cancel_work;
+
+       lock_sock(sk);
+
+       do_cancel_work = __mptcp_close(sk, timeout);
        release_sock(sk);
        if (do_cancel_work)
                mptcp_cancel_work(sk);

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 132d508..8f123d4 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -612,6 +612,7 @@ void mptcp_subflow_reset(struct sock *ssk);
 void mptcp_subflow_queue_clean(struct sock *ssk);
 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);
+bool __mptcp_close(struct sock *sk, long timeout);
 
 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
                           const struct mptcp_addr_info *b, bool use_port);