From mboxrd@z Thu Jan 1 00:00:00 1970 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 6576D492E42; Wed, 9 Sep 2026 18:07:25 +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=1788977246; cv=none; b=bdZIVeFitaYRKkWYI/P0LacdWmgKikO3/88D0KsqBNpKJBktvDp+cyNiTEG877LJ19k01t1TaWyAckwhocpYHQSdNfsmCSFKeBSUe1PnuMddA8L/iTEzbXI4OpqCYU88ESOtQh0orGm/HJEivUrZC3lBVJpINHoknqpj0DSM+Aw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788977246; c=relaxed/simple; bh=n7OTc5fFo6oGCdOW1SMqH4WBpt5JXMN8L2Y5Y4P0Gng=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VUbbbkvzAu/eXEpv2oQOjXCmQt5Qw/4LzIJKQU1X7mS2agmUtu9kOwooNDT5b3x3DHztbNop7Id3E+uKcC/6ywgkvlf1AKgtykg3gds7c3wP+Fv3pUPCDvRKdAMurIEFNh514ab3sukH2dvTfVo/CJw2ZcSW5RTwfv9MzXhaSKw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ik1cyO0n; 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="ik1cyO0n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E15471F000FF; Wed, 9 Sep 2026 18:07:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788977245; bh=gjumx+yxNIwFXOmGDVV5fmM1mA/kwdbL0yxvNc8CNG0=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ik1cyO0nALOSAuqMostZkNlp8WtbHEZo+jlPFQACnQrsnXlJZLvL2/FY9LL3iic+P sEgZ11Ge4rzCDNK7CTDDlvts1h7EngQkjD78oZMZYG4H2p0Y+Aq1HGq18xwdD2ICYb EQkokuXJOoehIRZJdTxlOsiyv4ecA7cExkYtZLyFHU3col6SolsTVWKGBzDj9r274u 14m62f3nLoIsmX7cjUGr5p6dUtqdt/RR79x5MtgvNSvufI6uU1r6kE9oW1LbGxM9SU 3BoCiMzIuuda/lrO9QUg+t3RZBbYoPCPfqqOrgs1kptl9hnrPRVsPP7ZLcWwgPdlcq gXlsX85finHAQ== Message-ID: <196b5e25-3e5b-42b1-861e-f67f976374eb@kernel.org> Date: Wed, 9 Sep 2026 20:07:20 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Thunderbird Daily Subject: Re: [PATCH net v2 15/15] mptcp: avoid pruning for OoW data Content-Language: fr To: Paolo Abeni , netdev-bot+sashiko@kernel.org Cc: martineau@kernel.org, geliang@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, horms@kernel.org, netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260908-net-mptcp-misc-fixes-7-3-rc1-v2-15-df1de70348b6@kernel.org> <178896537782.219967.1022060629733006428@kernel.org> <121f90e5-a19c-4066-af03-8cf5594bb30f@redhat.com> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Paolo, Thank you for having checked these comments. On 09/09/2026 17:50, Paolo Abeni wrote: > On 9/9/26 4:49 PM, netdev-bot+sashiko@kernel.org wrote: >> Thank you for your contribution! Sashiko AI review found 1 potential >> issue(s) to consider: >> >> Critical: 0 · High: 0 · Medium: 1 · Low: 0 >> >> - [Medium] Incomplete realization of the patch's stated principle ("do it >> only when we expect to accept the skb triggering the cleanup"): after… >> >> -- >> >> mptcp: avoid pruning for OoW data >> >> This moves the mptcp_try_rmem_schedule() call in mptcp_data_queue_ofo() >> so that it runs after the out-of-window check instead of before it, which >> avoids running the destructive OoO queue pruning for skbs that are going >> to be dropped as out of window. >> >>> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c >>> index 4309fca6b119..0098e2830931 100644 >>> --- a/net/mptcp/protocol.c >>> +++ b/net/mptcp/protocol.c >>> @@ -313,12 +313,6 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) >>> u64 seq, end_seq, max_seq; >>> struct sk_buff *skb1; >>> >>> - if (!mptcp_try_rmem_schedule(sk, skb)) { >>> - MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); >>> - mptcp_drop(sk, skb); >>> - return; >>> - } >>> - >>> seq = MPTCP_SKB_CB(skb)->map_seq; >>> end_seq = MPTCP_SKB_CB(skb)->end_seq; >>> max_seq = atomic64_read(&msk->rcv_wnd_sent); >>> @@ -335,6 +329,12 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) >>> return; >>> } >>> >>> + if (!mptcp_try_rmem_schedule(sk, skb)) { >>> + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); >>> + mptcp_drop(sk, skb); >>> + return; >>> + } >>> + >> >> [Severity: Medium] >> The commit message says pruning should be done "only when we expect >> to accept the skb triggering the cleanup". Does the new placement >> fully match that, given the duplicate-data check still happens later in >> the rbtree walk of mptcp_data_queue_ofo()? > > The change suggested here would add quite a bit of complexity for little > gain, and would diverge MPTCP behavior from TCP. We learned the lesson > the hard way we need very good reasons to do the latter. I'm pretty sure > we are better off with the proposed code. I agree with you. Cheers, Matt -- Sponsored by the NGI0 Core fund.