From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4702E21767D for ; Fri, 28 Aug 2026 03:49:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787888994; cv=none; b=BldIZJ5XWw4gT+pJUQpTSwzpIEed7lmNJ8i7CtAx+Q6xpR7HO6lQgt3TysBGt9ote49ECmepeZ/xDWCR1cAqZAWCy88iYU+4a03IcLUaZm/mVDYwy5APTcvs0kxex4o8vFXksM11eAdn6PSfuR5wvobgJF7YIbn0QOQybT59/N8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787888994; c=relaxed/simple; bh=fwNhWA7/HhhWlyx6Eqpb2J7lCcvZ1hmAHxC2ESYEDK4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O/Y4iUklzOfrF8PPsbrydtNits2TcIe3wVRT9PHcx4XuoFY/IB/F/CsvVp6Ygi80a0mjoElRXpC3+0Ww6+czRcu4mzJJjmaRsOUy13T43SoUVv6IfVuXc83JaoH9lrv9XJg/FR5qT5xufAgHhfbr6FdVvbY4MzNsCN4KL2+MWbM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B7cyK1Rp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B7cyK1Rp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63D051F00A3A; Fri, 28 Aug 2026 03:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787888993; bh=EbtbHCsIuO1lhJC8yuDXVRCqhrT67dAhhQnq/7Fqubg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=B7cyK1Rp00M+B2C/YhHR4D/FDQl31A4Rwuny8OA81b9OsuAK801Bvuse2UpuBiS2w BfJn/os3Jz8doRX82qVWbq4Scw2yx8amr8PMQTGrdb61bVTNpU/hUCXslbJnewGqNe QBmoJ7Hc6ghbmU8K+aJd2Ywv5TlP9aMf+qv1fwSU/iQz1CKIlaFJ9jR4ETi209rhGl KFZt6K5kX/U38NQ5gFBHz0uWQDVB2H0ZMpbTMveClUt9bgNNyZsPfgxJpI3xu5DGQ2 UVdCoX/Xrnnmpk4AtPxXKYBGbwArSgjT1q5wNLZ3Yhhg2ZxQfLpZ/oxNViwY9NZp1f wuGNlIarJWFFA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Paolo Abeni , Geliang Tang Subject: [PATCH mptcp-next v10 1/9] mptcp: drop the mptcp_ooo_try_coalesce() helper Date: Fri, 28 Aug 2026 11:49:36 +0800 Message-ID: X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni It's used to save an additional comparison for in-order skbs, but is also a barrier to remove CB offset. Remove the helper, let __mptcp_try_coalesce() always perform the sequence check and remove duplicate checks from the callers. Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Paolo Abeni --- net/mptcp/protocol.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f22d64ab1c53..7421b44934f0 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -167,7 +167,8 @@ static bool __mptcp_try_coalesce(struct sock *sk, struc= t sk_buff *to, { int limit =3D READ_ONCE(sk->sk_rcvbuf); =20 - if (unlikely(MPTCP_SKB_CB(to)->cant_coalesce) || + if (MPTCP_SKB_CB(from)->map_seq !=3D MPTCP_SKB_CB(to)->end_seq || + unlikely(MPTCP_SKB_CB(to)->cant_coalesce) || MPTCP_SKB_CB(from)->offset || ((to->len + from->len) > (limit >> 3)) || !skb_try_coalesce(to, from, fragstolen, delta)) @@ -200,15 +201,6 @@ static bool mptcp_try_coalesce(struct sock *sk, struct= sk_buff *to, return true; } =20 -static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff = *to, - struct sk_buff *from) -{ - if (MPTCP_SKB_CB(from)->map_seq !=3D MPTCP_SKB_CB(to)->end_seq) - return false; - - return mptcp_try_coalesce((struct sock *)msk, to, from); -} - /* "inspired" by tcp_rcvbuf_grow(), main difference: * - mptcp does not maintain a msk-level window clamp * - returns true when the receive buffer is actually updated @@ -348,7 +340,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk= , struct sk_buff *skb) /* with 2 subflows, adding at end of ooo queue is quite likely * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. */ - if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { + if (mptcp_try_coalesce(sk, msk->ooo_last_skb, skb)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); return; @@ -394,7 +386,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk= , struct sk_buff *skb) MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); goto merge_right; } - } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { + } else if (mptcp_try_coalesce(sk, skb1, skb)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); return; } @@ -777,8 +769,7 @@ static void __mptcp_add_backlog(struct sock *sk, if (!list_empty(&msk->backlog_list)) tail =3D list_last_entry(&msk->backlog_list, struct sk_buff, list); =20 - if (tail && MPTCP_SKB_CB(skb)->map_seq =3D=3D MPTCP_SKB_CB(tail)->end_seq= && - ssk =3D=3D tail->sk && + if (tail && ssk =3D=3D tail->sk && __mptcp_try_coalesce(sk, tail, skb, &fragstolen, &delta)) { skb->truesize -=3D delta; kfree_skb_partial(skb, fragstolen); @@ -902,7 +893,7 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk) =20 end_seq =3D MPTCP_SKB_CB(skb)->end_seq; tail =3D skb_peek_tail(&sk->sk_receive_queue); - if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { + if (!tail || !mptcp_try_coalesce(sk, tail, skb)) { int delta =3D msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; =20 /* skip overlapping data, if any */ --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7773912CDA5 for ; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XuGkjckY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A27F41F000E9; Fri, 28 Aug 2026 03:49:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787888995; bh=n/axowd3sv3CFZsC0rn2lMldjyCvrZv6vqeLfCa/H4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XuGkjckYM/e8GObSenz0p/0CI4DHOhYvyjIz/68Z9qmGgU8O6iS8CH7xFGhX8KkfE aG15MHQdnCIk+w+PgLXW6qeArysoMYPVpqVMmGmlE7x8OG22AwZ6Mue095Dynr8lJs LBZP4w11C3prb8DQ7kpUou+jdwJfyzts1n7Ss3D2xrm6oLlAz9GTMS0g8G/xBZGUX5 kz6BTI4JUuE44Ij4v7CH0uOpVRpAnHke+etAgWBfUzL0P7goDE8Qh1pcu/RKAbimo8 BA7W0dVzCCyr9HwFB2TaUq6FnamhmfQvO2fErrsoc9moubNOuhUwCOPs5oR+TRR1JD 86XynlQ7JMKZA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Paolo Abeni , Geliang Tang Subject: [PATCH mptcp-next v10 2/9] mptcp: drop the cant_coalesce CB field Date: Fri, 28 Aug 2026 11:49:37 +0800 Message-ID: X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni Such field is used to ensure in-sequence processing in case of fastopen. Instead let's perform synchronization of the fastopen skb sequence when the IASN becomes available with the 3rd ack. When the `cant_coalesce` field has been introduced, commit f03afb3aeb9d ("mptcp: drop __mptcp_fastopen_gen_msk_ackseq()") noted that updating the already queued skb for passive fastopen socket at 3rd ack time would be difficult and race prone. The main point is that such update don't need to be synchronously performed at 3rd ack time, but is sufficient to perform it before the next segment is introduced into the msk. To such extent, add an explicit test in __mptcp_move_skb(). Performance wise this trades a conditional in the fast path - in __mptcp_try_coalesce() - with a similar one in __mptcp_move_skb() and a couple more in slow paths. After this change the user-space will always observe consistent sequence numbers in the receive queue, even in the TFO dummy mapping case. There is still a potential race in mptcp_inq_hint() that will be addressed by a later patch in the series. Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Paolo Abeni --- net/mptcp/fastopen.c | 6 ++++-- net/mptcp/protocol.c | 35 +++++++++++++++++++++++++++++++++-- net/mptcp/protocol.h | 4 +++- net/mptcp/subflow.c | 10 ++++++++++ 4 files changed, 50 insertions(+), 5 deletions(-) diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c index f717750906ff..e18b31028e7e 100644 --- a/net/mptcp/fastopen.c +++ b/net/mptcp/fastopen.c @@ -9,6 +9,7 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context= *subflow, struct request_sock *req) { + struct mptcp_sock *msk; struct sock *sk, *ssk; struct sk_buff *skb; struct tcp_sock *tp; @@ -49,15 +50,16 @@ void mptcp_fastopen_subflow_synack_set_params(struct mp= tcp_subflow_context *subf MPTCP_SKB_CB(skb)->end_seq =3D 0; MPTCP_SKB_CB(skb)->offset =3D 0; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; - MPTCP_SKB_CB(skb)->cant_coalesce =3D 1; =20 mptcp_data_lock(sk); DEBUG_NET_WARN_ON_ONCE(sock_owned_by_user_nocheck(sk)); =20 + msk =3D mptcp_sk(sk); + msk->rcvd_dummy_seq =3D true; mptcp_borrow_fwdmem(sk, skb); skb_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); - mptcp_sk(sk)->bytes_received +=3D skb->len; + msk->bytes_received +=3D skb->len; =20 sk->sk_data_ready(sk); =20 diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 7421b44934f0..0a90bed02b41 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -168,7 +168,6 @@ static bool __mptcp_try_coalesce(struct sock *sk, struc= t sk_buff *to, int limit =3D READ_ONCE(sk->sk_rcvbuf); =20 if (MPTCP_SKB_CB(from)->map_seq !=3D MPTCP_SKB_CB(to)->end_seq || - unlikely(MPTCP_SKB_CB(to)->cant_coalesce) || MPTCP_SKB_CB(from)->offset || ((to->len + from->len) > (limit >> 3)) || !skb_try_coalesce(to, from, fragstolen, delta)) @@ -430,7 +429,6 @@ static void mptcp_init_skb(struct sock *ssk, struct sk_= buff *skb, int offset, MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + copy_len; MPTCP_SKB_CB(skb)->offset =3D offset; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; - MPTCP_SKB_CB(skb)->cant_coalesce =3D 0; =20 __skb_unlink(skb, &ssk->sk_receive_queue); =20 @@ -438,6 +436,26 @@ static void mptcp_init_skb(struct sock *ssk, struct sk= _buff *skb, int offset, skb_dst_drop(skb); } =20 +void __mptcp_sync_rcv_sequence(struct sock *sk) +{ + struct mptcp_sock *msk =3D mptcp_sk(sk); + struct sk_buff *skb; + u32 offset; + + if (likely(!msk->rcvd_dummy_seq)) + return; + + /* User space can have already received the TFO skb. */ + msk->rcvd_dummy_seq =3D false; + skb =3D skb_peek_tail(&sk->sk_receive_queue); + if (!skb) + return; + + offset =3D MPTCP_SKB_CB(skb)->offset; + MPTCP_SKB_CB(skb)->map_seq =3D msk->ack_seq - skb->len + offset; + MPTCP_SKB_CB(skb)->end_seq =3D msk->ack_seq; +} + static bool __mptcp_move_skb(struct sock *sk, struct sk_buff *skb) { u64 copy_len =3D MPTCP_SKB_CB(skb)->end_seq - MPTCP_SKB_CB(skb)->map_seq; @@ -446,6 +464,12 @@ static bool __mptcp_move_skb(struct sock *sk, struct s= k_buff *skb) =20 mptcp_borrow_fwdmem(sk, skb); =20 + /* Be sure to sync the eventual fastopen dummy mapping before any other + * skb lands into the msk. + */ + if (unlikely(msk->rcvd_dummy_seq)) + __mptcp_sync_rcv_sequence(sk); + if (MPTCP_SKB_CB(skb)->map_seq =3D=3D msk->ack_seq) { /* in sequence */ insert: @@ -3895,6 +3919,13 @@ static void mptcp_release_cb(struct sock *sk) __mptcp_error_report(sk); if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags)) __mptcp_sync_sndbuf(sk); + if (test_and_clear_bit(MPTCP_SYNC_SEQ, &msk->cb_flags)) { + /* Ensure we see the updated ack_seq after seeing + * the flag + */ + smp_rmb(); + __mptcp_sync_rcv_sequence(sk); + } } } =20 diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 3d250e8204d5..0b20cacf56a8 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -126,13 +126,13 @@ #define MPTCP_FLUSH_JOIN_LIST 5 #define MPTCP_SYNC_STATE 6 #define MPTCP_SYNC_SNDBUF 7 +#define MPTCP_SYNC_SEQ 8 =20 struct mptcp_skb_cb { u64 map_seq; u64 end_seq; u32 offset; u8 has_rxtstamp; - u8 cant_coalesce; }; =20 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) @@ -313,6 +313,7 @@ struct mptcp_sock { u32 token; unsigned long flags; unsigned long cb_flags; + bool rcvd_dummy_seq; bool recovery; /* closing subflow write queue reinjected */ bool can_ack; bool fully_established; @@ -1172,6 +1173,7 @@ void mptcp_event_pm_listener(const struct sock *ssk, enum mptcp_event_type event); bool mptcp_userspace_pm_active(const struct mptcp_sock *msk); =20 +void __mptcp_sync_rcv_sequence(struct sock *sk); void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context= *subflow, struct request_sock *req); int mptcp_pm_genl_fill_addr(struct sk_buff *msg, diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 2d7ccb01d234..ed3a48cf9c97 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -476,6 +476,8 @@ static void subflow_set_remote_key(struct mptcp_sock *m= sk, struct mptcp_subflow_context *subflow, const struct mptcp_options_received *mp_opt) { + struct sock *sk =3D (struct sock *)msk; 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Fri, 28 Aug 2026 03:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787888996; bh=DU6uxdmXUAt3Qp5y0EhZKQIHiihbeFvjBjE8/51IeWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Vyc8wzjpN/vTDNIKZIQrbByPQU1FgYSRCHNXQdtTeGqLWSesQ8N5/ItJgly2pn2t9 RclTf8s109TkXsCzL0QYgRc6I5q+IGkMm/VvUfkvr5YWY7s1FqMsXyUO22kd6bsfo8 NnyKUh9zjcY6pN+1W2a4MfHUTZ8+nZFYJKjU0uad8jH1AhSPrC+rkm3lrqqYAmmjbh v36FR5NEoEroQsizJ646nJz9DrOQKH/CRnmkSsfkQMHoAU77p/PAKzzTD0Bj/oHJq1 ZJdusae5cr8j8glfHOcAfnT6+FCPKhdnwjn8xFZe9jiM5VM5lg3RNkl6COq6liEMBH KvuP8eLBoohDw== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Paolo Abeni , Geliang Tang Subject: [PATCH mptcp-next v10 3/9] mptcp: remove CB offset field Date: Fri, 28 Aug 2026 11:49:38 +0800 Message-ID: X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni Instead, use a new msk-level field to track the bytes already consumed inside each skb, carrying the amount of bytes already copied to user-space, alike what TCP is already doing. The newly introduce `copied_seq` field is always accessed under the msk socket lock, delegating the synchronization with IASN to the msk release CB, when the socket is owned by the user-space at remote key reception time. Such synchronization preserves any partial progress (copy) made on the TFO packet. Note that the explicit synchronization in __mptcp_move_skb() is needed to ensure that the TFO skb in the receive queue got its map_seq synched before the next skb lands into the receive queue when spooling the backlog at mptcp_release_cb() time, as the release CB synchronization will happen later. Prior to this patch, the TFO skb dummy mapping was always ignored, now it affects the `copied_seq` initial update: be sure to extends the sign correctly of such mapping initialization time. Overall this simplify a bit the __mptcp_recvmsg_mskq(), mptcp_inq_hint() and the __mptcp_move_skb() code and will also make possible the next patch. Initialize MPTCP sequence space to 0 in mptcp_propagate_state() when mp_opt is NULL, ensuring SKB's map_seq starts from 0 to match msk->copied_seq and prevent offset calculation underflow in fallback mode. Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Paolo Abeni --- net/mptcp/fastopen.c | 9 ++-- net/mptcp/protocol.c | 113 ++++++++++++++++++++++--------------------- net/mptcp/protocol.h | 8 ++- net/mptcp/subflow.c | 9 ++++ 4 files changed, 79 insertions(+), 60 deletions(-) diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c index e18b31028e7e..421a50a85547 100644 --- a/net/mptcp/fastopen.c +++ b/net/mptcp/fastopen.c @@ -45,10 +45,11 @@ void mptcp_fastopen_subflow_synack_set_params(struct mp= tcp_subflow_context *subf subflow->ssn_offset +=3D skb->len; has_rxtstamp =3D TCP_SKB_CB(skb)->has_rxtstamp; =20 - /* Only the sequence delta is relevant */ - MPTCP_SKB_CB(skb)->map_seq =3D -skb->len; + /* The TFO segment data sits before the IASN; before receiving + * the remote key, IASN is assumed being 0. + */ + MPTCP_SKB_CB(skb)->map_seq =3D -(u64)skb->len; MPTCP_SKB_CB(skb)->end_seq =3D 0; - MPTCP_SKB_CB(skb)->offset =3D 0; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; =20 mptcp_data_lock(sk); @@ -56,6 +57,8 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptc= p_subflow_context *subf =20 msk =3D mptcp_sk(sk); msk->rcvd_dummy_seq =3D true; + msk->copied_seq =3D MPTCP_SKB_CB(skb)->map_seq; + msk->tfo_skb_len =3D skb->len; mptcp_borrow_fwdmem(sk, skb); skb_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 0a90bed02b41..02fe7272d1d4 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -29,7 +29,7 @@ #include "protocol.h" #include "mib.h" =20 -static unsigned int mptcp_inq_hint(const struct sock *sk); +static unsigned int mptcp_inq_hint(struct sock *sk); =20 #define CREATE_TRACE_POINTS #include @@ -168,7 +168,6 @@ static bool __mptcp_try_coalesce(struct sock *sk, struc= t sk_buff *to, int limit =3D READ_ONCE(sk->sk_rcvbuf); =20 if (MPTCP_SKB_CB(from)->map_seq !=3D MPTCP_SKB_CB(to)->end_seq || - MPTCP_SKB_CB(from)->offset || ((to->len + from->len) > (limit >> 3)) || !skb_try_coalesce(to, from, fragstolen, delta)) return false; @@ -415,8 +414,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk= , struct sk_buff *skb) skb_set_owner_r(skb, sk); } =20 -static void mptcp_init_skb(struct sock *ssk, struct sk_buff *skb, int offs= et, - int copy_len) +static void mptcp_init_skb(struct sock *ssk, struct sk_buff *skb, int offs= et) { struct mptcp_subflow_context *subflow =3D mptcp_subflow_ctx(ssk); bool has_rxtstamp =3D TCP_SKB_CB(skb)->has_rxtstamp; @@ -425,9 +423,9 @@ static void mptcp_init_skb(struct sock *ssk, struct sk_= buff *skb, int offset, * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq * value */ - MPTCP_SKB_CB(skb)->map_seq =3D mptcp_subflow_get_mapped_dsn(subflow); - MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + copy_len; - MPTCP_SKB_CB(skb)->offset =3D offset; + MPTCP_SKB_CB(skb)->map_seq =3D mptcp_subflow_get_mapped_dsn(subflow) - + offset; + MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + skb->len; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; =20 __skb_unlink(skb, &ssk->sk_receive_queue); @@ -440,7 +438,6 @@ void __mptcp_sync_rcv_sequence(struct sock *sk) { struct mptcp_sock *msk =3D mptcp_sk(sk); struct sk_buff *skb; - u32 offset; =20 if (likely(!msk->rcvd_dummy_seq)) return; @@ -451,9 +448,8 @@ void __mptcp_sync_rcv_sequence(struct sock *sk) if (!skb) return; =20 - offset =3D MPTCP_SKB_CB(skb)->offset; - MPTCP_SKB_CB(skb)->map_seq =3D msk->ack_seq - skb->len + offset; - MPTCP_SKB_CB(skb)->end_seq =3D msk->ack_seq; + MPTCP_SKB_CB(skb)->map_seq =3D mptcp_iasn(msk) - skb->len; + MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + skb->len; } =20 static bool __mptcp_move_skb(struct sock *sk, struct sk_buff *skb) @@ -464,6 +460,12 @@ static bool __mptcp_move_skb(struct sock *sk, struct s= k_buff *skb) =20 mptcp_borrow_fwdmem(sk, skb); =20 + if (test_and_clear_bit(MPTCP_SYNC_SEQ, &msk->cb_flags)) { + /* Ensure we see the updated ack_seq after seeing the flag */ + smp_rmb(); + msk->copied_seq +=3D mptcp_iasn(msk); + } + /* Be sure to sync the eventual fastopen dummy mapping before any other * skb lands into the msk. */ @@ -496,10 +498,6 @@ static bool __mptcp_move_skb(struct sock *sk, struct s= k_buff *skb) /* Partial packet */ if (after64(MPTCP_SKB_CB(skb)->end_seq, msk->ack_seq)) { copy_len =3D MPTCP_SKB_CB(skb)->end_seq - msk->ack_seq; - MPTCP_SKB_CB(skb)->offset +=3D msk->ack_seq - - MPTCP_SKB_CB(skb)->map_seq; - MPTCP_SKB_CB(skb)->map_seq +=3D msk->ack_seq - - MPTCP_SKB_CB(skb)->map_seq; goto insert; } =20 @@ -857,7 +855,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp= _sock *msk, if (offset < skb->len) { size_t len =3D skb->len - offset; =20 - mptcp_init_skb(ssk, skb, offset, len); + mptcp_init_skb(ssk, skb, offset); =20 if (own_msk) { mptcp_subflow_lend_fwdmem(subflow, skb); @@ -924,8 +922,6 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk) pr_debug("uncoalesced seq=3D%llx ack seq=3D%llx delta=3D%d\n", MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, delta); - MPTCP_SKB_CB(skb)->offset +=3D delta; - MPTCP_SKB_CB(skb)->map_seq +=3D delta; __skb_queue_tail(&sk->sk_receive_queue, skb); } msk->bytes_received +=3D end_seq - msk->ack_seq; @@ -2199,33 +2195,24 @@ static void mptcp_eat_recv_skb(struct sock *sk, str= uct sk_buff *skb) } =20 static int __mptcp_recvmsg_mskq(struct sock *sk, struct msghdr *msg, - size_t len, int flags, int copied_total, + size_t len, int flags, u64 *seq, struct scm_timestamping_internal *tss, int *cmsg_flags, struct sk_buff **last) { struct mptcp_sock *msk =3D mptcp_sk(sk); struct sk_buff *skb, *tmp; - int total_data_len =3D 0; int copied =3D 0; =20 skb_queue_walk_safe(&sk->sk_receive_queue, skb, tmp) { - u32 delta, offset =3D MPTCP_SKB_CB(skb)->offset; + u64 offset =3D *seq - MPTCP_SKB_CB(skb)->map_seq; u32 data_len =3D skb->len - offset; u32 count; int err; =20 - if (flags & MSG_PEEK) { - /* skip already peeked skbs */ - if (total_data_len + data_len <=3D copied_total) { - total_data_len +=3D data_len; - *last =3D skb; - continue; - } - - /* skip the already peeked data in the current skb */ - delta =3D copied_total - total_data_len; - offset +=3D delta; - data_len -=3D delta; + /* Skip the already peeked data. */ + if (offset >=3D skb->len) { + *last =3D skb; + continue; } =20 count =3D min_t(size_t, len - copied, data_len); @@ -2244,14 +2231,12 @@ static int __mptcp_recvmsg_mskq(struct sock *sk, st= ruct msghdr *msg, } =20 copied +=3D count; + *seq +=3D count; =20 if (!(flags & MSG_PEEK)) { msk->bytes_consumed +=3D count; - if (count < data_len) { - MPTCP_SKB_CB(skb)->offset +=3D count; - MPTCP_SKB_CB(skb)->map_seq +=3D count; + if (count < data_len) break; - } =20 mptcp_eat_recv_skb(sk, skb); } else { @@ -2404,25 +2389,27 @@ static bool mptcp_move_skbs(struct sock *sk) return enqueued; } =20 -static unsigned int mptcp_inq_hint(const struct sock *sk) +static unsigned int mptcp_inq_hint(struct sock *sk) { const struct mptcp_sock *msk =3D mptcp_sk(sk); - const struct sk_buff *skb; - - skb =3D skb_peek(&sk->sk_receive_queue); - if (skb) { - u64 hint_val =3D READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq; + u64 hint_val; =20 - if (hint_val >=3D INT_MAX) - return INT_MAX; - - return (unsigned int)hint_val; + /* Avoid races vs ack_seq updates and MPTCP_SYNC_SEQ flag. */ + mptcp_data_lock(sk); + if (test_bit(MPTCP_SYNC_SEQ, &msk->cb_flags)) { + mptcp_data_unlock(sk); + return 0; } + hint_val =3D msk->ack_seq - msk->copied_seq; + mptcp_data_unlock(sk); + if (hint_val >=3D INT_MAX) + return INT_MAX; =20 - if (sk->sk_state =3D=3D TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) + if (!hint_val && + (sk->sk_state =3D=3D TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))) return 1; =20 - return 0; + return (unsigned int)hint_val; } =20 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, @@ -2431,6 +2418,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msgh= dr *msg, size_t len, struct mptcp_sock *msk =3D mptcp_sk(sk); struct scm_timestamping_internal tss; int copied =3D 0, cmsg_flags =3D 0; + u64 peek_seq, *seq; int target; long timeo; =20 @@ -2449,6 +2437,11 @@ static int mptcp_recvmsg(struct sock *sk, struct msg= hdr *msg, size_t len, =20 len =3D min_t(size_t, len, INT_MAX); target =3D sock_rcvlowat(sk, flags & MSG_WAITALL, len); + seq =3D &msk->copied_seq; + if (flags & MSG_PEEK) { + peek_seq =3D msk->copied_seq; + seq =3D &peek_seq; + } =20 if (unlikely(msk->recvmsg_inq)) cmsg_flags =3D MPTCP_CMSG_INQ; @@ -2458,7 +2451,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msgh= dr *msg, size_t len, int err, bytes_read; =20 bytes_read =3D __mptcp_recvmsg_mskq(sk, msg, len - copied, flags, - copied, &tss, &cmsg_flags, + seq, &tss, &cmsg_flags, &last); if (unlikely(bytes_read < 0)) { if (!copied) @@ -2468,8 +2461,11 @@ static int mptcp_recvmsg(struct sock *sk, struct msg= hdr *msg, size_t len, =20 copied +=3D bytes_read; =20 - if (!list_empty(&msk->backlog_list) && mptcp_move_skbs(sk)) + if (!list_empty(&msk->backlog_list) && mptcp_move_skbs(sk)) { + if (flags & MSG_PEEK) + peek_seq =3D msk->copied_seq + copied; continue; + } =20 /* only the MPTCP socket status is relevant here. The exit * conditions mirror closely tcp_recvmsg() @@ -2513,6 +2509,10 @@ static int mptcp_recvmsg(struct sock *sk, struct msg= hdr *msg, size_t len, err =3D copied ? : err; goto out_err; } + + /* Recompute peek offset after eventual seq resync. */ + if (flags & MSG_PEEK) + peek_seq =3D msk->copied_seq + copied; } =20 mptcp_cleanup_rbuf(msk, copied); @@ -3690,11 +3690,13 @@ static int mptcp_disconnect(struct sock *sk, int fl= ags) msk->bytes_retrans =3D 0; msk->rcvspace_init =3D 0; msk->fastclosing =3D 0; + msk->tfo_skb_len =3D 0; mptcp_init_rtt_est(msk); =20 /* for fallback's sake */ WRITE_ONCE(msk->ack_seq, 0); atomic64_set(&msk->rcv_wnd_sent, 0); + msk->copied_seq =3D 0; =20 WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); @@ -3924,6 +3926,7 @@ static void mptcp_release_cb(struct sock *sk) * the flag */ smp_rmb(); + msk->copied_seq +=3D mptcp_iasn(msk); __mptcp_sync_rcv_sequence(sk); } } @@ -4588,7 +4591,7 @@ static struct sk_buff *mptcp_recv_skb(struct sock *sk= , u32 *off) mptcp_move_skbs(sk); =20 while ((skb =3D skb_peek(&sk->sk_receive_queue)) !=3D NULL) { - offset =3D MPTCP_SKB_CB(skb)->offset; + offset =3D msk->copied_seq - MPTCP_SKB_CB(skb)->map_seq; if (offset < skb->len) { *off =3D offset; return skb; @@ -4630,11 +4633,9 @@ static int __mptcp_read_sock(struct sock *sk, read_d= escriptor_t *desc, copied +=3D count; =20 msk->bytes_consumed +=3D count; - if (count < data_len) { - MPTCP_SKB_CB(skb)->offset +=3D count; - MPTCP_SKB_CB(skb)->map_seq +=3D count; + msk->copied_seq +=3D count; + if (count < data_len) break; - } =20 mptcp_eat_recv_skb(sk, skb); if (!desc->count) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 0b20cacf56a8..72a357b11b0f 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -131,7 +131,6 @@ struct mptcp_skb_cb { u64 map_seq; u64 end_seq; - u32 offset; u8 has_rxtstamp; }; =20 @@ -292,6 +291,7 @@ struct mptcp_sock { u64 bytes_sent; u64 snd_nxt; u64 bytes_received; + u64 copied_seq; u64 ack_seq; atomic64_t rcv_wnd_sent; u64 rcv_data_fin_seq; @@ -311,6 +311,7 @@ struct mptcp_sock { u32 last_ack_recv; unsigned long timer_ival; u32 token; + u32 tfo_skb_len; unsigned long flags; unsigned long cb_flags; bool rcvd_dummy_seq; @@ -865,6 +866,11 @@ struct sock *mptcp_subflow_get_retrans(struct mptcp_so= ck *msk); int mptcp_sched_get_send(struct mptcp_sock *msk); int mptcp_sched_get_retrans(struct mptcp_sock *msk); =20 +static inline u64 mptcp_iasn(const struct mptcp_sock *msk) +{ + return msk->ack_seq - msk->bytes_received + msk->tfo_skb_len; +} + static inline u64 mptcp_data_avail(const struct mptcp_sock *msk) { return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed); diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index ed3a48cf9c97..6b7a45710758 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -498,6 +498,8 @@ static void subflow_set_remote_key(struct mptcp_sock *m= sk, atomic64_set(&msk->rcv_wnd_sent, subflow->iasn); =20 if (!sock_owned_by_user(sk)) { + /* User space could have already read partially the TFO skb */ + msk->copied_seq +=3D subflow->iasn; 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charset="utf-8" From: Paolo Abeni The MPTCP protocol uses a significantly different CB layout WRT TCP, as it includes different information and use 64 bits for the sequence numbers. As the msk-level rcvbuf buffer size is limited by the core socket code the INT_MAX; after validating the incoming skb vs the current receive window, we can safely use 32 bits for MPTCP-level sequence number. This allow updating the MPTCP CB layout so that fields with a corresponding TCP-level data use the same area inside the CB itself. Add build time check to ensure the latter invariant. Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Paolo Abeni --- net/mptcp/fastopen.c | 6 ++-- net/mptcp/protocol.c | 85 +++++++++++++++++++++++++++----------------- net/mptcp/protocol.h | 7 ++-- 3 files changed, 61 insertions(+), 37 deletions(-) diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c index 421a50a85547..0d339dd454f9 100644 --- a/net/mptcp/fastopen.c +++ b/net/mptcp/fastopen.c @@ -48,8 +48,10 @@ void mptcp_fastopen_subflow_synack_set_params(struct mpt= cp_subflow_context *subf /* The TFO segment data sits before the IASN; before receiving * the remote key, IASN is assumed being 0. */ - MPTCP_SKB_CB(skb)->map_seq =3D -(u64)skb->len; + MPTCP_SKB_CB(skb)->map_seq64 =3D -(u64)skb->len; + MPTCP_SKB_CB(skb)->map_seq =3D MPTCP_SKB_CB(skb)->map_seq64; MPTCP_SKB_CB(skb)->end_seq =3D 0; + MPTCP_SKB_CB(skb)->flags =3D 0; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; =20 mptcp_data_lock(sk); @@ -57,7 +59,7 @@ void mptcp_fastopen_subflow_synack_set_params(struct mptc= p_subflow_context *subf =20 msk =3D mptcp_sk(sk); msk->rcvd_dummy_seq =3D true; - msk->copied_seq =3D MPTCP_SKB_CB(skb)->map_seq; + msk->copied_seq =3D MPTCP_SKB_CB(skb)->map_seq64; msk->tfo_skb_len =3D skb->len; mptcp_borrow_fwdmem(sk, skb); skb_set_owner_r(skb, sk); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 02fe7272d1d4..76b8d7253e79 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -172,7 +172,7 @@ static bool __mptcp_try_coalesce(struct sock *sk, struc= t sk_buff *to, !skb_try_coalesce(to, from, fragstolen, delta)) return false; =20 - pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n", + pr_debug("colesced seq %x into %x new len %d new end seq %x\n", MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, to->len, MPTCP_SKB_CB(from)->end_seq); MPTCP_SKB_CB(to)->end_seq =3D MPTCP_SKB_CB(from)->end_seq; @@ -254,8 +254,8 @@ static void mptcp_prune_ofo_queue(struct sock *sk, struct sk_buff *skb =3D rb_to_skb(node); =20 /* Stop pruning if the incoming skb would land in OoO tail. */ - if (after64(MPTCP_SKB_CB(in_skb)->map_seq, - MPTCP_SKB_CB(skb)->map_seq)) + if (after(MPTCP_SKB_CB(in_skb)->map_seq, + MPTCP_SKB_CB(skb)->map_seq)) break; =20 pruned =3D true; @@ -301,15 +301,19 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *m= sk, struct sk_buff *skb) { struct sock *sk =3D (struct sock *)msk; struct rb_node **p, *parent; - u64 seq, end_seq, max_seq; + u64 end_seq, max_seq; struct sk_buff *skb1; + u32 seq; =20 seq =3D MPTCP_SKB_CB(skb)->map_seq; - end_seq =3D MPTCP_SKB_CB(skb)->end_seq; + end_seq =3D MPTCP_SKB_CB(skb)->map_seq64 + skb->len; max_seq =3D atomic64_read(&msk->rcv_wnd_sent); =20 - pr_debug("msk=3D%p seq=3D%llx limit=3D%llx empty=3D%d\n", msk, seq, max_s= eq, + pr_debug("msk=3D%p seq=3D%x limit=3D%llx empty=3D%d\n", msk, seq, max_seq, RB_EMPTY_ROOT(&msk->out_of_order_queue)); + /* Use the full sequence space to perform the admission checks, to + * protect vs possible wrap-arounds. + */ if (after64(end_seq, max_seq)) { /* out of window */ mptcp_drop(sk, skb); @@ -345,7 +349,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk= , struct sk_buff *skb) } =20 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ - if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { + if (!before(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); parent =3D &msk->ooo_last_skb->rbnode; p =3D &parent->rb_right; @@ -357,18 +361,18 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *m= sk, struct sk_buff *skb) while (*p) { parent =3D *p; skb1 =3D rb_to_skb(parent); - if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { + if (before(seq, MPTCP_SKB_CB(skb1)->map_seq)) { p =3D &parent->rb_left; continue; } - if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { - if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { + if (before(seq, MPTCP_SKB_CB(skb1)->end_seq)) { + if (!after(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { /* All the bits are present. Drop. */ mptcp_drop(sk, skb); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); return; } - if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { + if (after(seq, MPTCP_SKB_CB(skb1)->map_seq)) { /* partial overlap: * | skb | * | skb1 | @@ -399,7 +403,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk= , struct sk_buff *skb) merge_right: /* Remove other segments covered by skb. */ while ((skb1 =3D skb_rb_next(skb)) !=3D NULL) { - if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) + if (before((u32)end_seq, MPTCP_SKB_CB(skb1)->end_seq)) break; rb_erase(&skb1->rbnode, &msk->out_of_order_queue); mptcp_drop(sk, skb1); @@ -421,11 +425,13 @@ static void mptcp_init_skb(struct sock *ssk, struct s= k_buff *skb, int offset) =20 /* the skb map_seq accounts for the skb offset: * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq - * value + * value; note that end seq number is only available in 32bits format. */ - MPTCP_SKB_CB(skb)->map_seq =3D mptcp_subflow_get_mapped_dsn(subflow) - - offset; + MPTCP_SKB_CB(skb)->map_seq64 =3D mptcp_subflow_get_mapped_dsn(subflow) - + offset; + MPTCP_SKB_CB(skb)->map_seq =3D (u32)MPTCP_SKB_CB(skb)->map_seq64; MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + skb->len; + MPTCP_SKB_CB(skb)->flags =3D 0; MPTCP_SKB_CB(skb)->has_rxtstamp =3D has_rxtstamp; =20 __skb_unlink(skb, &ssk->sk_receive_queue); @@ -448,13 +454,14 @@ void __mptcp_sync_rcv_sequence(struct sock *sk) if (!skb) return; =20 - MPTCP_SKB_CB(skb)->map_seq =3D mptcp_iasn(msk) - skb->len; + MPTCP_SKB_CB(skb)->map_seq64 =3D mptcp_iasn(msk) - skb->len; + MPTCP_SKB_CB(skb)->map_seq =3D (u32)MPTCP_SKB_CB(skb)->map_seq64; MPTCP_SKB_CB(skb)->end_seq =3D MPTCP_SKB_CB(skb)->map_seq + skb->len; } =20 static bool __mptcp_move_skb(struct sock *sk, struct sk_buff *skb) { - u64 copy_len =3D MPTCP_SKB_CB(skb)->end_seq - MPTCP_SKB_CB(skb)->map_seq; + u32 copy_len =3D MPTCP_SKB_CB(skb)->end_seq - MPTCP_SKB_CB(skb)->map_seq; struct mptcp_sock *msk =3D mptcp_sk(sk); struct sk_buff *tail; =20 @@ -472,7 +479,7 @@ static bool __mptcp_move_skb(struct sock *sk, struct sk= _buff *skb) if (unlikely(msk->rcvd_dummy_seq)) __mptcp_sync_rcv_sequence(sk); =20 - if (MPTCP_SKB_CB(skb)->map_seq =3D=3D msk->ack_seq) { + if (MPTCP_SKB_CB(skb)->map_seq64 =3D=3D msk->ack_seq) { /* in sequence */ insert: if (!mptcp_try_rmem_schedule(sk, skb)) { @@ -490,14 +497,14 @@ static bool __mptcp_move_skb(struct sock *sk, struct = sk_buff *skb) skb_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); return true; - } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { + } else if (after64(MPTCP_SKB_CB(skb)->map_seq64, msk->ack_seq)) { mptcp_data_queue_ofo(msk, skb); return false; } =20 /* Partial packet */ - if (after64(MPTCP_SKB_CB(skb)->end_seq, msk->ack_seq)) { - copy_len =3D MPTCP_SKB_CB(skb)->end_seq - msk->ack_seq; + if (after64(MPTCP_SKB_CB(skb)->map_seq64 + skb->len, msk->ack_seq)) { + copy_len =3D MPTCP_SKB_CB(skb)->end_seq - (u32)msk->ack_seq; goto insert; } =20 @@ -892,40 +899,40 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk) { struct sock *sk =3D (struct sock *)msk; struct sk_buff *skb, *tail; + u32 seq_delta, ack_seq; bool moved =3D false; struct rb_node *p; - u64 end_seq; =20 p =3D rb_first(&msk->out_of_order_queue); pr_debug("msk=3D%p empty=3D%d\n", msk, RB_EMPTY_ROOT(&msk->out_of_order_q= ueue)); while (p) { + ack_seq =3D msk->ack_seq; skb =3D rb_to_skb(p); - if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) + if (after(MPTCP_SKB_CB(skb)->map_seq, ack_seq)) break; =20 p =3D rb_next(p); rb_erase(&skb->rbnode, &msk->out_of_order_queue); =20 - if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, - msk->ack_seq))) { + if (unlikely(!after(MPTCP_SKB_CB(skb)->end_seq, ack_seq))) { mptcp_drop(sk, skb); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); continue; } =20 - end_seq =3D MPTCP_SKB_CB(skb)->end_seq; + seq_delta =3D MPTCP_SKB_CB(skb)->end_seq - ack_seq; tail =3D skb_peek_tail(&sk->sk_receive_queue); if (!tail || !mptcp_try_coalesce(sk, tail, skb)) { - int delta =3D msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; + int delta =3D ack_seq - MPTCP_SKB_CB(skb)->map_seq; =20 /* skip overlapping data, if any */ - pr_debug("uncoalesced seq=3D%llx ack seq=3D%llx delta=3D%d\n", - MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, + pr_debug("uncoalesced seq=3D%x ack seq=3D%x delta=3D%d\n", + MPTCP_SKB_CB(skb)->map_seq, ack_seq, delta); __skb_queue_tail(&sk->sk_receive_queue, skb); } - msk->bytes_received +=3D end_seq - msk->ack_seq; - WRITE_ONCE(msk->ack_seq, end_seq); + msk->bytes_received +=3D seq_delta; + WRITE_ONCE(msk->ack_seq, msk->ack_seq + seq_delta); moved =3D true; } return moved; @@ -2204,7 +2211,7 @@ static int __mptcp_recvmsg_mskq(struct sock *sk, stru= ct msghdr *msg, int copied =3D 0; =20 skb_queue_walk_safe(&sk->sk_receive_queue, skb, tmp) { - u64 offset =3D *seq - MPTCP_SKB_CB(skb)->map_seq; + u32 offset =3D (u32)(*seq) - MPTCP_SKB_CB(skb)->map_seq; u32 data_len =3D skb->len - offset; u32 count; int err; @@ -4591,7 +4598,7 @@ static struct sk_buff *mptcp_recv_skb(struct sock *sk= , u32 *off) mptcp_move_skbs(sk); =20 while ((skb =3D skb_peek(&sk->sk_receive_queue)) !=3D NULL) { - offset =3D msk->copied_seq - MPTCP_SKB_CB(skb)->map_seq; + offset =3D (u32)msk->copied_seq - MPTCP_SKB_CB(skb)->map_seq; if (offset < skb->len) { *off =3D offset; return skb; @@ -4842,11 +4849,23 @@ static int mptcp_napi_poll(struct napi_struct *napi= , int budget) return work_done; } =20 +#define CHK_CB_FIELD(mptcp_field, tcp_field) \ + ({ \ + BUILD_BUG_ON(offsetof(struct mptcp_skb_cb, mptcp_field) !=3D \ + offsetof(struct tcp_skb_cb, tcp_field)); \ + BUILD_BUG_ON(offsetofend(struct mptcp_skb_cb, mptcp_field) !=3D \ + offsetofend(struct tcp_skb_cb, tcp_field)); \ + }) + void __init mptcp_proto_init(void) { struct mptcp_delegated_action *delegated; int cpu; =20 + CHK_CB_FIELD(map_seq, seq); + CHK_CB_FIELD(end_seq, end_seq); + CHK_CB_FIELD(flags, tcp_flags); + mptcp_prot.h.hashinfo =3D tcp_prot.h.hashinfo; =20 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 72a357b11b0f..3a677a88ee4c 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -129,9 +129,12 @@ #define MPTCP_SYNC_SEQ 8 =20 struct mptcp_skb_cb { - u64 map_seq; - u64 end_seq; + u32 map_seq; + u32 end_seq; + u32 unused; + u16 flags; u8 has_rxtstamp; + u64 map_seq64; }; =20 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7123A12CDA5 for ; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U5rHmV/9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9342A1F00A3A; Fri, 28 Aug 2026 03:49:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787889001; bh=WuzxPKujeTvC2ZmggqKQHmqzH8iGfS9ynaZ34rMJRRs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=U5rHmV/9ZYposNwIZSvx9bDYmFFz72KxG6IoLk4+ffz95bu9PKDrAhKGIB77nDqyb yYoxGQyz18kspnyTc4mv6SRMAeiYwhYJlmuEkO6lqxsDQnOrOvFVwUC2eqyneMrYzk StUQlVPJos9auI2nq7uupPJBeo6lxfZ8mJxWdBywP9ztNZqwe5hiZi/V3NtfkPVgGh 5vxsDtWzxi++cS+6Oec38oCLy4LvWdtA2zw6XBI4XnQxqOnvcf5PqVVboUwGX8cvhS z3y0Kpo8HSd7eHVs2HX4kZdL7DEYFf6xY5hOJiUi2aC49SK3p3k07x0thvIuZMAU0h 1du3xKFzmKa5g== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Paolo Abeni , Geliang Tang Subject: [PATCH mptcp-next v10 5/9] mptcp: defer read_sock cleanup to mptcp_worker Date: Fri, 28 Aug 2026 11:49:40 +0800 Message-ID: <7e4395d627eb370b40c4ee4ebda25af44a302c87.1787888115.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni When MPTCP carries TLS, the data path runs under mptcp_data_lock(). Reaching sk->sk_data_ready(sk) synchronously ends up at tls_strp_check_rcv() -> mptcp_recv_skb() -> mptcp_move_skbs(), which calls mptcp_data_lock() on the same sk and recurses on sk_lock.slock. The TLS path is not the only constraint: before the mptcp_recv_skb() calls, the TLS code would also reach __mptcp_read_sock(), which calls mptcp_rcv_space_adjust() and mptcp_cleanup_rbuf(). Both require holding the msk socket lock in process context, while the mptcp/TLS caller is in BH scope. Fix this by deferring sk->sk_data_ready(sk) to mptcp_worker() via a new MPTCP_WORK_READ_COMPLETE bit, reusing the existing mptcp_schedule_work()/ mptcp_cancel_work() infrastructure. The wakeup bit is consumed after the SOCK_DEAD && TCP_CLOSE destroy branch, so a socket that reaches the destroy path drops the pending wakeup rather than running it post-free. Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Paolo Abeni --- net/mptcp/protocol.c | 32 ++++++++++++++++++++++++-------- net/mptcp/protocol.h | 2 ++ 2 files changed, 26 insertions(+), 8 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 76b8d7253e79..fce85967b90e 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3140,6 +3140,20 @@ static void mptcp_backlog_purge(struct sock *sk) sk_mem_reclaim(sk); } =20 +static void mptcp_read_complete(struct sock *sk) +{ + struct mptcp_sock *msk =3D mptcp_sk(sk); + int read_copied; + + mptcp_data_lock(sk); + read_copied =3D msk->read_copied; + msk->read_copied =3D 0; + mptcp_data_unlock(sk); + + mptcp_rcv_space_adjust(msk, read_copied); + mptcp_cleanup_rbuf(msk, read_copied); +} + static void mptcp_do_fastclose(struct sock *sk) { struct mptcp_subflow_context *subflow, *tmp; @@ -3216,6 +3230,9 @@ static void mptcp_worker(struct work_struct *work) if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) __mptcp_retrans(sk); =20 + if (test_and_clear_bit(MPTCP_WORK_READ_COMPLETE, &msk->flags)) + mptcp_read_complete(sk); + fail_tout =3D msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_= tout) : 0; if (fail_tout && time_after(jiffies, fail_tout)) mptcp_mp_fail_no_response(msk); @@ -4594,9 +4611,6 @@ static struct sk_buff *mptcp_recv_skb(struct sock *sk= , u32 *off) struct sk_buff *skb; u32 offset; =20 - if (!list_empty(&msk->backlog_list)) - mptcp_move_skbs(sk); - while ((skb =3D skb_peek(&sk->sk_receive_queue)) !=3D NULL) { offset =3D (u32)msk->copied_seq - MPTCP_SKB_CB(skb)->map_seq; if (offset < skb->len) { @@ -4611,6 +4625,7 @@ static struct sk_buff *mptcp_recv_skb(struct sock *sk= , u32 *off) /* * Note: * - It is assumed that the socket was locked by the caller. + * - Can be invoked in BH scope. */ static int __mptcp_read_sock(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor, bool noack) @@ -4620,8 +4635,6 @@ static int __mptcp_read_sock(struct sock *sk, read_de= scriptor_t *desc, int copied =3D 0; u32 offset; =20 - msk_owned_by_me(msk); - if (sk->sk_state =3D=3D TCP_LISTEN) return -ENOTCONN; while ((skb =3D mptcp_recv_skb(sk, &offset)) !=3D NULL) { @@ -4652,11 +4665,14 @@ static int __mptcp_read_sock(struct sock *sk, read_= descriptor_t *desc, if (noack) goto out; =20 - mptcp_rcv_space_adjust(msk, copied); - + /* The backlog flushing is only needed when some data is actually + * moved and will take place in the workers's release callback. + */ if (copied > 0) { mptcp_recv_skb(sk, &offset); - mptcp_cleanup_rbuf(msk, copied); + msk->read_copied +=3D copied; + set_bit(MPTCP_WORK_READ_COMPLETE, &msk->flags); + mptcp_schedule_work(sk); } out: return copied; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 3a677a88ee4c..f08803593d66 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -117,6 +117,7 @@ #define MPTCP_FALLBACK_DONE 2 #define MPTCP_WORK_CLOSE_SUBFLOW 3 #define MPTCP_RTX_DISABLED 4 +#define MPTCP_WORK_READ_COMPLETE 5 =20 /* MPTCP socket release cb flags */ #define MPTCP_PUSH_PENDING 1 @@ -312,6 +313,7 @@ struct mptcp_sock { u32 last_data_sent; u32 last_data_recv; u32 last_ack_recv; + int read_copied; unsigned long timer_ival; u32 token; u32 tfo_skb_len; --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C19FF12CDA5 for ; Fri, 28 Aug 2026 03:50:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889004; cv=none; b=VZyy8BHXo7ZvsPjkKWZB/cKeh+RXKmIKuka083BQZvDxDeB/XHe+qPT3gMvMnERukmRHd2WKLyOnFHh5UER12PCUhJPKI5Ezc98lA1HY6JT2Jr4EdocWH7HU5QAmQu18iy20XlNgf7eyZOvV9Rp7qLrFEcVdo2CSvcZ8f17hBYM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889004; c=relaxed/simple; bh=Yr2rvvCPOEbX8lnjYcZWjShkrHHyeeRNOKtYSYi7eOc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=djbobuAgDxR6iBD68QbIRSrJBgugi7kTBqfqza/9q4lYGy8+OLW90YmSuUXTwCpCFxmmNRasVEt7fmSuSMttzb61ZUdAhQ8prs84iTyM6gLkXkw+4iKWqnLA3sFc+wRuZ0vNizHsr2PGfdMPyZ5kPdTXhlMm32dN07l2BBr1zrQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UULEZ85F; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UULEZ85F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B77541F000E9; Fri, 28 Aug 2026 03:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787889002; bh=vfE3RsbAv2c1Fr+CsaC79TsKvMlVA2REfohMpi3zKik=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UULEZ85FEEBZg/Rk0AYl/+QrJVB+KPQQB5OGhrWSpABphBeReAfrkQzX+iLeCHNGc RkjefebujE+uGXS4g/6T5KZQ/0nEAi2ZWCP7CaW00+qftE37bj3+qY6X4v1BHoV34S qXcJ6gPg7Iu2wUFZjCXwVYtgxGkpBFpOQKkLkpWbkgtoBNVlzq8p2CCAieToDnYZI0 Hbzs9Nw/fv6DS5tS1ljzf5FX65cPU9B41MBu0ie2sM7sztE98PSx4M5Wv+Scs6rFba z3HVg+TujQDRVG713/FHCi8+nbn+02PKs9eZ+DL5L2QQ+jFctW7MudSKqTPiYFqpt1 MbPotgBUctVKg== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v10 6/9] mptcp: implement peek_len for proto_ops Date: Fri, 28 Aug 2026 11:49:41 +0800 Message-ID: <7b1fabcac57f36b0723d6ec1cac7b20dab1bbf86.1787888115.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang Add mptcp_inq() to compute the number of readable bytes at the MPTCP level. It derives the count from ack_seq - copied_seq, returns 0 while the connection is still handshaking (TCP_SYN_SENT/TCP_SYN_RECV), and subtracts 1 once a FIN has been received, mirroring tcp_inq(). The subtraction is needed because MPTCP's ack_seq is incremented by 1 in mptcp_check_data_fin() when the DATA_FIN is processed, consuming a sequence number without carrying any payload data. Without subtracting 1, peek_len would over-report by one byte, causing upper layers to wait for data that will never arrive. READ_ONCE() is used instead of mptcp_data_lock() for the u64 reads of ack_seq and copied_seq because mptcp_inq() will be called from TLS contexts with the socket lock held - taking the spinlock would deadlock. On 32-bit systems a torn read can produce a wrapped subtraction (close to 2^64), which is caught by the INT_MAX clamp. TLS callers use mptcp_inq() conservatively: over-reporting defers work to the next iteration, where recvmsg() provides the actual byte count. Wire mptcp_inq() into mptcp_peek_len() and assign .peek_len in both mptcp_stream_ops and mptcp_v6_stream_ops, so upper layers get the correct in-queue byte count for MPTCP connections. Signed-off-by: Geliang Tang --- net/mptcp/protocol.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index fce85967b90e..639122b7845a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -4797,6 +4797,39 @@ static ssize_t mptcp_splice_read(struct socket *sock= , loff_t *ppos, return ret; } =20 +static int mptcp_inq(struct sock *sk) +{ + const struct mptcp_sock *msk =3D mptcp_sk(sk); + int answ; + + if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { + answ =3D 0; + } else if (test_bit(MPTCP_SYNC_SEQ, &msk->cb_flags)) { + answ =3D 0; + } else { + u64 hint_val; + + hint_val =3D READ_ONCE(msk->ack_seq) - READ_ONCE(msk->copied_seq); + if (hint_val >=3D INT_MAX) + hint_val =3D INT_MAX; + + answ =3D (unsigned int)hint_val; + + /* Subtract 1, if FIN was received. Mirror tcp_inq() */ + if (answ && + (sk->sk_state =3D=3D TCP_CLOSE || + (sk->sk_shutdown & RCV_SHUTDOWN))) + answ--; + } + + return answ; +} + +static int mptcp_peek_len(struct socket *sock) +{ + return mptcp_inq(sock->sk); +} + static const struct proto_ops mptcp_stream_ops =3D { .family =3D PF_INET, .owner =3D THIS_MODULE, @@ -4819,6 +4852,7 @@ static const struct proto_ops mptcp_stream_ops =3D { .set_rcvlowat =3D mptcp_set_rcvlowat, .read_sock =3D mptcp_read_sock, .splice_read =3D mptcp_splice_read, + .peek_len =3D mptcp_peek_len, }; =20 static struct inet_protosw mptcp_protosw =3D { @@ -4943,6 +4977,7 @@ static const struct proto_ops mptcp_v6_stream_ops =3D= { .set_rcvlowat =3D mptcp_set_rcvlowat, .read_sock =3D mptcp_read_sock, .splice_read =3D mptcp_splice_read, + .peek_len =3D mptcp_peek_len, }; =20 static struct proto mptcp_v6_prot; --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE9751684B0 for ; Fri, 28 Aug 2026 03:50:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889005; cv=none; b=iWo7QIHgFs0c+4yOZ0dRfPB3G68wd4tUaS9+rDsiuYR2JbQVGP9FxUmqaNCEjcSAYWs/Y3SQtLrtImDAIPDX4KT31PcQ2AA87sDMAgxdtgy/7XKIKNHTY0/MTlkYSZ4MmtNdRf/2efJdg713/fukZUu8T+JjMkDaHHuFctaWx2Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889005; c=relaxed/simple; bh=XV3NRNgxDUKvOh+JPK9Ru0w+4PS+cCR/nPEQnWlCq44=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ksziq7ZaMjhoBafh9nubV+QNaN0fGaBQTJ9y7KZDRDyuBclT004Z3omaLWzCQCkhu/VeYf/fPMesiTXYA4panIu7U/WijS26qi1Jz/tRUBxjuHZUkUeMxkDui+Hwl/iDkkkHiKWiOsqfymS4r0EQmlI7JTp/0CQ02k+enHwFQnI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KS60eIee; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KS60eIee" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A8A1F00A3A; Fri, 28 Aug 2026 03:50:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787889004; bh=D/MlYChVtIFbsKJYwRAxuXWWNybUK4TwW00jCHIRzAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KS60eIeeo4d9NS05PTjkAazMYCqWpgeuUpVI7HH/XPXzNpetoft9CozyApbLoxaaB 7p2iSm93VPLNbGcTHT8w49zEL+c12Hd0PwDcmbZ6hUA/luRIhtL51i64Yku6PdXKOW trUcuJjesrOwwcRyfG5pS1mtiZePADGvDV5FvahNbKIueE5pK6q/zCcYs5MFQaJVC6 EhHqVBSFjbbhjG1dem0zSv1wQDxw9oz2NPkhtwoz1oUe79Yz8tQMjyNBDy2Jwj8PRs lyUeHONN0/UfK+JIEwZoZCrdSVvMZOYR41sp78GWvEpx3QJVxbCvKRN+qAcq4CU3KU PYDjm/EDTRREg== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v10 7/9] mptcp: add sendmsg_locked to proto_ops Date: Fri, 28 Aug 2026 11:49:42 +0800 Message-ID: <818d871690900ca5558a86bcff23adae5de280b3.1787888115.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang MPTCP currently provides a standard sendmsg() implementation which acquires and releases the socket lock internally. However, certain upper layers need to call the sendmsg method while the socket lock is already held. Split the existing mptcp_sendmsg() into mptcp_sendmsg_locked() which assumes the caller holds the socket lock, and a tiny wrapper mptcp_sendmsg() that acquires the lock and calls the locked version. Expose .sendmsg_locked in both mptcp_stream_ops and mptcp_v6_stream_ops. Signed-off-by: Geliang Tang --- net/mptcp/protocol.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 639122b7845a..141d905e4921 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2048,7 +2048,7 @@ static void mptcp_rps_record_subflows(const struct mp= tcp_sock *msk) } } =20 -static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) +static int mptcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_= t len) { struct mptcp_sock *msk =3D mptcp_sk(sk); struct page_frag *pfrag; @@ -2060,8 +2060,6 @@ static int mptcp_sendmsg(struct sock *sk, struct msgh= dr *msg, size_t len) msg->msg_flags &=3D MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN | MSG_EOR; =20 - lock_sock(sk); - mptcp_rps_record_subflows(msk); =20 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) || @@ -2177,7 +2175,6 @@ static int mptcp_sendmsg(struct sock *sk, struct msgh= dr *msg, size_t len) } =20 out: - release_sock(sk); return copied; =20 do_error: @@ -2188,6 +2185,17 @@ static int mptcp_sendmsg(struct sock *sk, struct msg= hdr *msg, size_t len) goto out; } =20 +static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) +{ + int ret; + + lock_sock(sk); + ret =3D mptcp_sendmsg_locked(sk, msg, len); + release_sock(sk); + + return ret; +} + static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied); =20 static void mptcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb) @@ -4853,6 +4861,7 @@ static const struct proto_ops mptcp_stream_ops =3D { .read_sock =3D mptcp_read_sock, .splice_read =3D mptcp_splice_read, .peek_len =3D mptcp_peek_len, + .sendmsg_locked =3D mptcp_sendmsg_locked, }; =20 static struct inet_protosw mptcp_protosw =3D { @@ -4978,6 +4987,7 @@ static const struct proto_ops mptcp_v6_stream_ops =3D= { .read_sock =3D mptcp_read_sock, .splice_read =3D mptcp_splice_read, .peek_len =3D mptcp_peek_len, + .sendmsg_locked =3D mptcp_sendmsg_locked, }; =20 static struct proto mptcp_v6_prot; --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10E921684B0 for ; Fri, 28 Aug 2026 03:50:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889008; cv=none; b=TwpkIj7DAxnvV+uDZGza0GMDbfkdNDII4aacuyCJzbaqpdLlGUN9UH/eSdNIvKV7Xvr2DRcEdROev6A1ayY7pyQ25X3YIloboSqRaBMquBwz4lecVvVroKVz61Iv9+xboV6WA8rgljtrPHA61fbgS3WmjbBnOkf6QgsbpcdhJcY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889008; c=relaxed/simple; bh=PMsTK8o3q/WDu5iJNM0pq9G0FBQwIIpXUscAkbWzRK0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HNulVCMF/5gObyee6wigSGUyNrQe6Y1Z0Mgl6NG+NYk9FS/knHjE50pNELIsB6x/KgJBKHkeSeXlpdhpvAynD66b/r45PcwBNDz3EgFhIadZtkq3Etf1PzctFasT7b3H2p9cOlvo1k5nMhtR8osQQZxwIB+/rTMFW2vlcr/GKK4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kAFV7Qq8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kAFV7Qq8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B36F1F000E9; Fri, 28 Aug 2026 03:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787889006; bh=qQ657pJJXWGksM+Kj68wSpSlAt0lLDwrVsNLvPnfkis=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kAFV7Qq83XNxabOJ06G0fJNEJ0dWgUo3PjGjHbXaJMMjlgxVt3Dq0LJYlgkCwDmTS cRoL1fIRVw03YEqpdBeX8ioprN2D4F2sN0Ys8M4Yg+/VOwmAPxjjPLgjnxDnHsoFWJ J5cdAMNOjalkHtT6rb1afpUuUw+M3gy2x+2Gff268SHPxhujcO8NyER14+7HaKc8YS hpabrPwDEf2VcaUCzPJrhkMJYXL4PzH8grTRTqelGY2AOfLDzZqCnmlWP1hwVTxJNT ah5jG9o0G1gN9NvUqi8RlLq9+hpPqGPjof8MkdkjN0A7pd0GoPdIMhdVNOsGH1pvUa 5NhXY/7yskaKg== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v10 8/9] mptcp: track app-limited state in mptcp_sendmsg Date: Fri, 28 Aug 2026 11:49:43 +0800 Message-ID: <0d2bee1bd2baa7ccc03026cc89d23aa77b019cc1.1787888115.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang The application-limited accounting in TCP is updated by tcp_rate_check_app_limited(), which currently takes a struct sock * and internally calls tcp_sk(). MPTCP needs to apply the same accounting to each subflow individually - every subflow is an independent TCP socket with its own tp->app_limited / delivered state - so wrapping the call as a struct sock * -> tcp_sk() helper is awkward at the call site. Split the existing function: keep the logic as tcp_sock_rate_check_app_limited(struct tcp_sock *tp), and turn tcp_rate_check_app_limited(struct sock *) into a thin wrapper so the exported API is unchanged for other TCP users. Then add mptcp_sock_rate_check_app_limited() that walks every subflow of the mptcp_sock and runs tcp_sock_rate_check_app_limited() under each subflow's socket lock. Invoke it from mptcp_sendmsg() right after the send-side setup, so the delivery-rate app_limited state stays in sync with what the application actually has to send across each subflow. With this in place, TCP_INFO.tcpi_delivery_rate_app_limited is reported correctly for MPTCP connections instead of being left at 0. Signed-off-by: Geliang Tang --- include/net/tcp.h | 1 + net/ipv4/tcp.c | 9 +++++++-- net/mptcp/protocol.c | 18 ++++++++++++++++++ 3 files changed, 26 insertions(+), 2 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 670c20876f26..f5cbb5a8a288 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -849,6 +849,7 @@ static inline int tcp_bound_to_half_wnd(struct tcp_sock= *tp, int pktsize) =20 /* tcp.c */ void tcp_get_info(struct sock *, struct tcp_info *); +void tcp_sock_rate_check_app_limited(struct tcp_sock *tp); void tcp_rate_check_app_limited(struct sock *sk); =20 /* Read 'sendfile()'-style from a TCP socket */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 1452c40e22d4..f0f843fd1897 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1096,9 +1096,9 @@ int tcp_sendmsg_fastopen(struct sock *sk, struct msgh= dr *msg, int *copied, } =20 /* If a gap is detected between sends, mark the socket application-limited= . */ -void tcp_rate_check_app_limited(struct sock *sk) +void tcp_sock_rate_check_app_limited(struct tcp_sock *tp) { - struct tcp_sock *tp =3D tcp_sk(sk); + struct sock *sk =3D (struct sock *)tp; =20 if (/* We have less than one packet to send. */ tp->write_seq - tp->snd_nxt < tp->mss_cache && @@ -1111,6 +1111,11 @@ void tcp_rate_check_app_limited(struct sock *sk) tp->app_limited =3D (tp->delivered + tcp_packets_in_flight(tp)) ? : 1; } + +void tcp_rate_check_app_limited(struct sock *sk) +{ + tcp_sock_rate_check_app_limited(tcp_sk(sk)); +} EXPORT_SYMBOL_GPL(tcp_rate_check_app_limited); =20 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 141d905e4921..1419bd065b38 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2048,6 +2048,21 @@ static void mptcp_rps_record_subflows(const struct m= ptcp_sock *msk) } } =20 +static void mptcp_rate_check_app_limited(struct sock *sk) +{ + struct mptcp_sock *msk =3D mptcp_sk(sk); + struct mptcp_subflow_context *subflow; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk =3D mptcp_subflow_tcp_sock(subflow); + bool slow; + + slow =3D lock_sock_fast_nested(ssk); + tcp_sock_rate_check_app_limited(tcp_sk(ssk)); + unlock_sock_fast(ssk, slow); + } +} + static int mptcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_= t len) { struct mptcp_sock *msk =3D mptcp_sk(sk); @@ -2076,6 +2091,9 @@ static int mptcp_sendmsg_locked(struct sock *sk, stru= ct msghdr *msg, size_t len) =20 timeo =3D sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); =20 + /* is sending application-limited? */ + mptcp_rate_check_app_limited(sk); + if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { ret =3D sk_stream_wait_connect(sk, &timeo); if (ret) --=20 2.53.0 From nobody Sat Sep 5 05:49:06 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5A091684B0 for ; Fri, 28 Aug 2026 03:50:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889009; cv=none; b=MmlNnDj0mO3i9j97GFgqW5A23HituaPLmPkJlyZRItHdINNSvbp2OFvubpgXFP32gBHbEwb12jhDUnzA9uZOlMf78NPtNVj5oe9QDL0u2zcW71X/+JD2ZqegGvyIki7P7QaiLOLl9pnGOfs8YOMopqY19G2touZLSjByXkfIsK4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787889009; c=relaxed/simple; bh=JxT3qeiSHuBS12KtGnTPLFRzVxKd0fvCXwqrRkI3nnM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VivBSODtgRaTHJyZrVVQZSzOXCzPcweKgmuFIi8toLCuodTBR3VUWxn/E+Ew1mmhU1yVD0ai1Yd+M0Ds2uyYBp/51uLFHqX8IqMbTCuA3UgFRQXtwi5d6Qkwf2TO1qtZtfKIg/gF8Qhkz6iIYoMu2kQNOxzVFxYes5oYIp6H84U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X4+x7yNi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X4+x7yNi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44E891F00A3A; Fri, 28 Aug 2026 03:50:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787889008; bh=xNNDwMcimuhvgxiiYj/oGzahS6NB1VtBfCB7+LyvfjA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=X4+x7yNibGrAIOmMkhEgaIzuVFu61Ud1GspCbc1yuOvWlU5VyqOtVmGz/TSpTNhbu I5jp+T6VdhR09LZHa2xhKTIA4ZHBh1/BQscsHKU/J35V6FOy64NkZQc0Bmj/niuCxa D6YkPfwjiWvHdA7k0wbp24wFhSlyvxy3SP36IXfs/+GkjRTZjUbFPyKW8lFca4KcXP IQpqM+0GDOML0jbbd3H+cMbjjcwGh6SgY8UW7uB3i9VcepAVLlwyklpR8i45T5AB4u LQXxTGPbaaB6Bjj6ml1p/4xFyG4tq1rOGOja++uT6tthCei5B5zlKKvkEOj/CijWNs 1CKci1mbzacXA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v10 9/9] selftests: mptcp: sockopt: check app_limited Date: Fri, 28 Aug 2026 11:49:44 +0800 Message-ID: <90391cc3e5d2728c76aeabf2a59d49078de692b7.1787888115.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang connect_one_server() in mptcp_sockopt exchanges only a few packets between the client and server, then closes the socket. After such a small transfer the application has nothing further to send, so the connection is, by definition, application-limited. Extend the TCP_INFO readback at the end of the function to assert s.tcp_info.tcpi_delivery_rate_app_limited =3D=3D 1. Without the preceding commit, mptcp_sendmsg() never updates the per-subflow app-limited state, and this field stays at 0 - the assertion would fail. With it in place, the value is forced to 1, turning this into a regression guard for the subflow-side application-limited accounting. Signed-off-by: Geliang Tang --- tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c b/tools/test= ing/selftests/net/mptcp/mptcp_sockopt.c index d68515b7903b..8d712bdb4325 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c +++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c @@ -640,6 +640,7 @@ static void connect_one_server(int fd, int pipefd) total +=3D 1; /* sequence advances due to FIN */ =20 assert(s.mptcpi_rcv_delta =3D=3D (uint64_t)total); + assert(s.tcp_info.tcpi_delivery_rate_app_limited =3D=3D 1); close(fd); } =20 --=20 2.53.0