From mboxrd@z Thu Jan 1 00:00:00 1970 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 31BED1420A8 for ; Thu, 15 Feb 2024 22:20:04 +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=1708035605; cv=none; b=GmpTWwKk1eahwiD+I00cKzYb2Ndj+1cKwt34yd+xxKJKiJ4TVLpF9gwC/M8/0utHUnzakAG8uSqLVXqtFIdwD3lfG64zigf6U8oxGXnPgQjY8i1LWVV1ApXyt7SaB/wnU2WFFvP/FgNO6bV0x9g/F8ZgHzZGmEWz0qlHephIXmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708035605; c=relaxed/simple; bh=n/qtvCVXhbH8YxjFV6TDuSZIkG+0QwQccbzArK73GBU=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=DQ8wvglKlA82lQ4yIHCB1LaSv3eCHDauy3G/xVDTx9tqLN/3vGTJmatR2tbrpkdGyHBkCNMgTrJPk35Ss2LrhEke8v54iNfQPBps4nN7CeH9xHWOULzNnFR6HRqkE7WHaG6/kZHWjpqXA2uc6xvVq783lV/2Niz7CgMf3g2VChE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c3LiqTT5; 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="c3LiqTT5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99C2AC433C7; Thu, 15 Feb 2024 22:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708035604; bh=n/qtvCVXhbH8YxjFV6TDuSZIkG+0QwQccbzArK73GBU=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=c3LiqTT5GNvPpg3AQGUlNlJ7traK0JjaD7cQM8HdvxZEfC4ckfDqEa0OyX1jiOadQ ci/GPndNMaxq2jVejQIRFtTLK0zfGGoKBsXkiEwBSAaEgbsB/ICv1S/0/2NZ1CUP2k xRLNvAygAcJ93k+LtbqOi8X4l6amCFOLPudYqUb0icMLXgIHNC1k3X+zFUgXMRGlki +30O8+66iNu3+NU+cicWQymg+d+qcivxKCLDYkQhySLmpUr+v8BrJNQZ+M6FIXT7o+ /5tOT9YVstisEMrzumOFgXpi+RbhzMNrvUvqCvmMy1EMMXBFxzUvHOb/iBzM+cmelm VBsJZZMBfh20A== Date: Thu, 15 Feb 2024 14:20:03 -0800 (PST) From: Mat Martineau To: Paolo Abeni cc: mptcp@lists.linux.dev Subject: Re: [mptcp-next v2 3/7] mptcp: fix potential wake-up event loss In-Reply-To: <78924a15f3d86f989fa286f10ef88670b790eb89.1707739536.git.pabeni@redhat.com> Message-ID: <27696500-0456-ef2d-164b-d6c7a30a459e@kernel.org> References: <78924a15f3d86f989fa286f10ef88670b790eb89.1707739536.git.pabeni@redhat.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed On Mon, 12 Feb 2024, Paolo Abeni wrote: > After the blamed commit below, the send buffer auto-tuning can > happen after that the mptcp_propagate_sndbuf() completes - via > the delegated action infrastructure. > > We must check for write space even after such change or we risk > missing the wake-up event. > > Fixes: 8005184fd1ca ("mptcp: refactor sndbuf auto-tuning") > Signed-off-by: Paolo Abeni > --- > net/mptcp/protocol.h | 27 ++++++++++++++++++++------- > 1 file changed, 20 insertions(+), 7 deletions(-) > > diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h > index 486fff865803..2e197262a42e 100644 > --- a/net/mptcp/protocol.h > +++ b/net/mptcp/protocol.h > @@ -797,6 +797,16 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk) > READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt); > } > > +static inline void mptcp_write_space(struct sock *sk) > +{ > + if (sk_stream_is_writeable(sk)) { > + /* pairs with memory barrier in mptcp_poll */ > + smp_mb(); > + if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags)) > + sk_stream_write_space(sk); > + } > +} > + > static inline void __mptcp_sync_sndbuf(struct sock *sk) > { > struct mptcp_subflow_context *subflow; > @@ -815,6 +825,7 @@ static inline void __mptcp_sync_sndbuf(struct sock *sk) > > /* the msk max wmem limit is * tcp wmem[2] */ > WRITE_ONCE(sk->sk_sndbuf, new_sndbuf); > + mptcp_write_space(sk); > } > > /* The called held both the msk socket and the subflow socket locks, > @@ -845,14 +856,16 @@ static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk) > local_bh_enable(); > } > > -static inline void mptcp_write_space(struct sock *sk) > +static inline void __mptcp_sync_sndnxt(struct sock *sk, u64 new_snd_nxt) Hi Paolo - I think you missed my comment on this in v1, __mptcp_sync_sndnxt() isn't called anywhere. - Mat > { > - if (sk_stream_is_writeable(sk)) { > - /* pairs with memory barrier in mptcp_poll */ > - smp_mb(); > - if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags)) > - sk_stream_write_space(sk); > - } > + struct mptcp_sock *msk = mptcp_sk(sk); > + > + if (!after64(new_snd_nxt, msk->snd_nxt)) > + return; > + > + msk->bytes_sent += new_snd_nxt - msk->snd_nxt; > + WRITE_ONCE(msk->snd_nxt, new_snd_nxt); > + mptcp_write_space(sk); > } > > void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags); > -- > 2.43.0 > > >