mptcp: decouple mptcp fastclose from tcp close

commit fff0c87996672816a84c3386797a5e69751c5888 upstream.

With the current fastclose implementation, the mptcp_do_fastclose()
helper is in charge of two distinct actions: send the fastclose reset
and cleanup the subflows.

Formally decouple the two steps, ensuring that mptcp explicitly closes
all the subflows after the mentioned helper.

This will make the upcoming fix simpler, and allows dropping the 2nd
argument from mptcp_destroy_common(). The Fixes tag is then the same as
in the next commit to help with the backports.

Fixes: d21f83485518 ("mptcp: use fastclose on more edge scenarios")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-5-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1adb5790a0821e871c9045a0bc55da96635c7e13..6c1f96f6ae392e972cfb5cc6d2426817956746d3 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2869,7 +2869,11 @@ static void mptcp_worker(struct work_struct *work)
                __mptcp_close_subflow(sk);
 
        if (mptcp_close_tout_expired(sk)) {
+               struct mptcp_subflow_context *subflow, *tmp;
+
                mptcp_do_fastclose(sk);
+               mptcp_for_each_subflow_safe(msk, subflow, tmp)
+                       __mptcp_close_ssk(sk, subflow->tcp_sock, subflow, 0);
                mptcp_close_wake_up(sk);
        }
 
@@ -3301,7 +3305,8 @@ static int mptcp_disconnect(struct sock *sk, int flags)
        /* msk->subflow is still intact, the following will not free the first
         * subflow
         */
-       mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
+       mptcp_do_fastclose(sk);
+       mptcp_destroy_common(msk);
 
        /* The first subflow is already in TCP_CLOSE status, the following
         * can't overlap with a fallback anymore
@@ -3483,7 +3488,7 @@ void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
                msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
 }
 
-void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
+void mptcp_destroy_common(struct mptcp_sock *msk)
 {
        struct mptcp_subflow_context *subflow, *tmp;
        struct sock *sk = (struct sock *)msk;
@@ -3492,7 +3497,7 @@ void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
 
        /* join list will be eventually flushed (with rst) at sock lock release time */
        mptcp_for_each_subflow_safe(msk, subflow, tmp)
-               __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
+               __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, 0);
 
        /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
        mptcp_data_lock(sk);
@@ -3517,7 +3522,7 @@ static void mptcp_destroy(struct sock *sk)
 
        /* allow the following to close even the initial subflow */
        msk->free_first = 1;
-       mptcp_destroy_common(msk, 0);
+       mptcp_destroy_common(msk);
        sk_sockets_allocated_dec(sk);
 }
 

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 0239bb19203e206e9a69c9c13a533ec687d0dc65..73b8423506779db56ffbe1d1de1b5a54e303a1db 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -968,7 +968,7 @@ static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
        local_bh_enable();
 }
 
-void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
+void mptcp_destroy_common(struct mptcp_sock *msk);
 
 #define MPTCP_TOKEN_MAX_RETRIES        4