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 598A91EA95 for ; Thu, 12 Oct 2023 14:15:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O9bQeEZg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2026C433C7; Thu, 12 Oct 2023 14:15:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697120130; bh=cDwPyE2G9VnNDzAmqYsaAR7S9xCOKP/9xzz/GFUutAg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=O9bQeEZgI2BXknaYUInGvAyV2y9R86qCEeYAkVgGp9QL6pRyherJFa6mZnl6dlrZ3 x7kC5iCZ9mOWI0aYyXn1CmGtRZaGpclYbyytOHJnGKDKlN5LzOv7oGUC6nlNziQIM+ VXwOD/77DSKkvxjGIkiGr7wyMs7dJy9G6JbP8SrM8bWDv7VEJJyuiNNrm1WtdhF6oa 6h7tU1KViXGV71B7i+6D4w0+bWLNDXlPhl21so9kpxKhRUFrczSLr9aoADg81Aw+UK suPMdv0XsXkBI8ejx1Giv+8xcDDoHk1Rqyl8yIF33XGLZA3HQ60jwxH5w5tujgo6SJ mp2wNTL/cApvw== Message-ID: Date: Thu, 12 Oct 2023 16:15:27 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mptcp-next v14 3/7] mptcp: add __mptcp_subflow_disconnect helper Content-Language: en-GB, fr-BE To: Geliang Tang Cc: Paolo Abeni , mptcp@lists.linux.dev References: <73963454-bb2d-48b8-9202-666fc2fc5ba7@kernel.org> <20231012090350.GA30030@localhost.localdomain> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Geliang, On 12/10/2023 11:03, Geliang Tang wrote: > Hi Matt, > > On Wed, Oct 11, 2023 at 06:53:17PM +0200, Matthieu Baerts wrote: >> Hi Geliang, Paolo, >> >> On 11/10/2023 15:34, Geliang Tang wrote: >>> When closing the msk->first socket in __mptcp_close_ssk(), if there's >>> another subflow available, it's better to avoid resetting it, just shut >>> down it. >>> >>> This patch adds a new helper __mptcp_subflow_disconnect(), and reuse >>> flag MPTCP_CF_FASTCLOSE in this case. When MPTCP_CF_FASTCLOSE isn't set, >>> we invoke tcp_shutdown() instead of tcp_disconnect(). >>> >>> Co-developed-by: Paolo Abeni >>> Signed-off-by: Paolo Abeni >>> Signed-off-by: Geliang Tang >>> --- >>> net/mptcp/protocol.c | 28 ++++++++++++++++++++++------ >>> 1 file changed, 22 insertions(+), 6 deletions(-) >>> >>> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c >>> index 30e0c29ae0a4..1a54d55f8bb2 100644 >>> --- a/net/mptcp/protocol.c >>> +++ b/net/mptcp/protocol.c >>> @@ -2366,6 +2366,26 @@ bool __mptcp_retransmit_pending_data(struct sock *sk) >>> #define MPTCP_CF_PUSH BIT(1) >>> #define MPTCP_CF_FASTCLOSE BIT(2) >>> >>> +/* be sure to send a reset only if the caller asked for it, also >>> + * clean completely the subflow status when the subflow reaches >>> + * TCP_CLOSE state >>> + */ >>> +static void __mptcp_subflow_disconnect(struct sock *ssk, >>> + struct mptcp_subflow_context *subflow, >>> + unsigned int flags) >>> +{ >>> + if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || >>> + (flags & MPTCP_CF_FASTCLOSE)) { >>> + /* The MPTCP code never wait on the subflow sockets, TCP-level >>> + * disconnect should never fail >>> + */ >>> + WARN_ON_ONCE(tcp_disconnect(ssk, 0)); >>> + mptcp_subflow_ctx_reset(subflow); >>> + } else { >>> + tcp_shutdown(ssk, SEND_SHUTDOWN); >> >> I didn't check in detail but should we not also call >> __mptcp_subflow_error_report()? > > When the socket shuts down, it's state is TCPF_FIN_WAIT2. > __mptcp_subflow_error_report will return and do nothing in this case: > > if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) > return false; > > So no need to call __mptcp_subflow_error_report. > >> >> And maybe other helpers? What is done between the 'goto out' and the >> 'out' label in __mptcp_close_ssk() here below? → what we do when other >> subflows are being closed. > > No need to go the following path too: > > sock_put(ssk); > > if (ssk == msk->first) > WRITE_ONCE(msk->first, NULL); > > So we can keep this patch as it. Thank you for having check the two cases! All good then! Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net