From nobody Fri Oct 18 06:17:02 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7B8F479E1 for ; Mon, 27 May 2024 10:36:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716806186; cv=none; b=GACQkQRxMUIk/EZqbK4BEjdoOYIb9ODifEOHZEqe4mlXtDjd3BZMcnCLFAT3E9qCExiGs6sjAlhFjoE0oHpyfujSZ2JNPHPTnzy+z+qSJIBJmGjAZgQrO4TvD76fs0vZk7GmHSfK1JRPZSyJhq09hv96Rl0XyYRjW+NySFwQQOg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716806186; c=relaxed/simple; bh=xIMMGDr+WsAJfAO4pKTmvR7l+M5cTxCQLjLj8tnB+Fg=; h=Message-ID:Date:MIME-Version:Subject:References:From:To:Cc: In-Reply-To:Content-Type; b=U3XcynpZp3+cvfLjdAfkR4FGeu3C/tj/AxMonySuo/nLyffApKTqonDG+p88ZbCcPNlON/4RaVxBpnEKpEKDeGgAUOLigLv6/it+M3L6V5YfEA4TYi2L+PalGLQa1wFTCsT2Y7IIgoii/wH+Q/6+rkM8NMerjsTxOKdw1ZUz+9A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aa2ey2EI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aa2ey2EI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E72CC2BBFC; Mon, 27 May 2024 10:36:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716806186; bh=xIMMGDr+WsAJfAO4pKTmvR7l+M5cTxCQLjLj8tnB+Fg=; h=Date:Subject:References:From:To:Cc:In-Reply-To:From; b=aa2ey2EIlx906Fpt7a6Fsp/u/37qITm/2Af34QOctUPPRCa1i9q6JNvrGensXRZDd CcNbg3mYIA/6ZGIFzeiIwafM+Pfuy1zMpJHlSngsRVmov3YQhsZfMfcgaXgKvFHcq/ yc5QLnTGc7unmdFa6wnrENug7m6js5A/C7q8n2EP6RI8yBlG4uLru1J5JUk5E28Ocd rNmfmT3cNBLKL/VeUud2pfRVL5hEbuc0+KCrFA2MhO7M8U9i+iUo/2HyXEL+4R2EQE Ora6RH5cnqY3j8B9AeDD+PVMizos+ZFghHpacjMboNbqGl+26cN9jHYvlaFl38uVMS CQuB1Bkz5DGIA== Message-ID: Date: Mon, 27 May 2024 12:36:23 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Fwd: Patch "mptcp: implement TCP_NOTSENT_LOWAT support" has been added to the 6.8-stable tree References: <20240526173559.3483900-1-sashal@kernel.org> Content-Language: en-GB From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset="utf-8" Hi Paolo, It looks like your series adding TCP_NOTSENT_LOWAT support (4 patches) has been selected to be backported to v6.8 to ease the backport of "mptcp: fix full TCP keep-alive support". I was going to complain, but it doesn't seem to hurt, only adding an isolated feature, and most importantly, v6.8 will likely be marked as EOL in less than a month. No objections then? Cheers, Matt -------- Forwarded Message -------- Subject: Patch "mptcp: implement TCP_NOTSENT_LOWAT support" has been added to the 6.8-stable tree Date: Sun, 26 May 2024 13:35:59 -0400 From: Sasha Levin Reply-To: stable@vger.kernel.org To: stable-commits@vger.kernel.org, pabeni@redhat.com CC: Matthieu Baerts , Mat Martineau , Geliang Tang , David S. Miller , Eric Dumazet , Jakub Kicinski This is a note to let you know that I've just added the patch titled mptcp: implement TCP_NOTSENT_LOWAT support to the 6.8-stable tree which can be found at: http://www.kernel.org/git/?p=3Dlinux/kernel/git/stable/stable-queue.git;a= =3Dsummary The filename of the patch is: mptcp-implement-tcp_notsent_lowat-support.patch and it can be found in the queue-6.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. commit 2a46eda8186692bbbf798c05afd9481c5d708887 Author: Paolo Abeni Date: Fri Mar 1 18:43:46 2024 +0100 mptcp: implement TCP_NOTSENT_LOWAT support [ Upstream commit 29b5e5ef87397963ca38d3eec0d296ad1c979bbc ] Add support for such socket option storing the user-space provided value in a new msk field, and using such data to implement the _mptcp_stream_memory_free() helper, similar to the TCP one. To avoid adding more indirect calls in the fast path, open-code a variant of sk_stream_memory_free() in mptcp_sendmsg() and add direct calls to the mptcp stream memory free helper where possible. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/464 Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Stable-dep-of: bd11dc4fb969 ("mptcp: fix full TCP keep-alive support") Signed-off-by: Sasha Levin diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index fcd85adc621c1..54e29ab911f0d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1757,6 +1757,30 @@ static int do_copy_data_nocache(struct sock *sk, int copy, return 0; } +/* open-code sk_stream_memory_free() plus sent limit computation to + * avoid indirect calls in fast-path. + * Called under the msk socket lock, so we can avoid a bunch of ONCE + * annotations. + */ +static u32 mptcp_send_limit(const struct sock *sk) +{ + const struct mptcp_sock *msk =3D mptcp_sk(sk); + u32 limit, not_sent; + + if (sk->sk_wmem_queued >=3D READ_ONCE(sk->sk_sndbuf)) + return 0; + + limit =3D mptcp_notsent_lowat(sk); + if (limit =3D=3D UINT_MAX) + return UINT_MAX; + + not_sent =3D msk->write_seq - msk->snd_nxt; + if (not_sent >=3D limit) + return 0; + + return limit - not_sent; +} + static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) { struct mptcp_sock *msk =3D mptcp_sk(sk); @@ -1801,6 +1825,12 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) struct mptcp_data_frag *dfrag; bool dfrag_collapsed; size_t psize, offset; + u32 copy_limit; + + /* ensure fitting the notsent_lowat() constraint */ + copy_limit =3D mptcp_send_limit(sk); + if (!copy_limit) + goto wait_for_memory; /* reuse tail pfrag, if possible, or carve a new one from the * page allocator @@ -1808,9 +1838,6 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) dfrag =3D mptcp_pending_tail(sk); dfrag_collapsed =3D mptcp_frag_can_collapse_to(msk, pfrag, dfrag); if (!dfrag_collapsed) { - if (!sk_stream_memory_free(sk)) - goto wait_for_memory; - if (!mptcp_page_frag_refill(sk, pfrag)) goto wait_for_memory; @@ -1825,6 +1852,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) offset =3D dfrag->offset + dfrag->data_len; psize =3D pfrag->size - offset; psize =3D min_t(size_t, psize, msg_data_left(msg)); + psize =3D min_t(size_t, psize, copy_limit); total_ts =3D psize + frag_truesize; if (!sk_wmem_schedule(sk, total_ts)) @@ -3761,6 +3789,7 @@ static struct proto mptcp_prot =3D { .unhash =3D mptcp_unhash, .get_port =3D mptcp_get_port, .forward_alloc_get =3D mptcp_forward_alloc_get, + .stream_memory_free =3D mptcp_stream_memory_free, .sockets_allocated =3D &mptcp_sockets_allocated, .memory_allocated =3D &tcp_memory_allocated, @@ -3932,12 +3961,12 @@ static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) { struct sock *sk =3D (struct sock *)msk; - if (sk_stream_is_writeable(sk)) + if (__mptcp_stream_is_writeable(sk, 1)) return EPOLLOUT | EPOLLWRNORM; set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */ - if (sk_stream_is_writeable(sk)) + if (__mptcp_stream_is_writeable(sk, 1)) return EPOLLOUT | EPOLLWRNORM; return 0; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 6b83869ef7938..2f17f295d7c8b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -305,6 +305,7 @@ struct mptcp_sock { in_accept_queue:1, free_first:1, rcvspace_init:1; + u32 notsent_lowat; struct work_struct work; struct sk_buff *ooo_last_skb; struct rb_root out_of_order_queue; @@ -789,11 +790,36 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk) READ_ONCE(msk->write_seq) =3D=3D READ_ONCE(msk->snd_nxt); } +static inline u32 mptcp_notsent_lowat(const struct sock *sk) +{ + struct net *net =3D sock_net(sk); + u32 val; + + val =3D READ_ONCE(mptcp_sk(sk)->notsent_lowat); + return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); +} + +static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake) +{ + const struct mptcp_sock *msk =3D mptcp_sk(sk); + u32 notsent_bytes; + + notsent_bytes =3D READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt); + return (notsent_bytes << wake) < mptcp_notsent_lowat(sk); +} + +static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake) +{ + return mptcp_stream_memory_free(sk, wake) && + __sk_stream_is_writeable(sk, wake); +} + static inline void mptcp_write_space(struct sock *sk) { /* pairs with memory barrier in mptcp_poll */ smp_mb(); - sk_stream_write_space(sk); + if (mptcp_stream_memory_free(sk, 1)) + sk_stream_write_space(sk); } static inline void __mptcp_sync_sndbuf(struct sock *sk) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 82d0cd0819f09..f2fe28a3912a9 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -810,6 +810,16 @@ static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, return 0; case TCP_ULP: return -EOPNOTSUPP; + case TCP_NOTSENT_LOWAT: + ret =3D mptcp_get_int_option(msk, optval, optlen, &val); + if (ret) + return ret; + + lock_sock(sk); + WRITE_ONCE(msk->notsent_lowat, val); + mptcp_write_space(sk); + release_sock(sk); + return 0; case TCP_CONGESTION: return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen); case TCP_CORK: @@ -1343,6 +1353,8 @@ static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname, return mptcp_put_int_option(msk, optval, optlen, msk->cork); case TCP_NODELAY: return mptcp_put_int_option(msk, optval, optlen, msk->nodelay); + case TCP_NOTSENT_LOWAT: + return mptcp_put_int_option(msk, optval, optlen, msk->notsent_lowat); } return -EOPNOTSUPP; }