From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (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 670212D7DDE for ; Wed, 5 Nov 2025 22:59:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762383554; cv=none; b=cXxHPK/PjZH7jkd5BQa5SUtQtjKilYfzLmkjxex3l7RYBwG973F0b+RLeEAl74YqiB4o/aS0dMtnuF4mMfjihRd+A+DjMQRThlHSNEp1jSIfQigs6SHrn6srpbadwiyS9uoJVuv0WvCgq4bWIIysMZnxxysqCSpfkufKXVj7RZM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762383554; c=relaxed/simple; bh=CPuuHp7pZQpd6tLnAgipCfEtZDhJg4P3Ocuzr1bEB+o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OEYco7X0avh/2LBNgirg1Nb/7NE64pabQ9F2ygZfsvePdwE1RbwucPL9lIRgzdrRgMDG6qyqh6Pp7D+6Sw7OwZlC5LD0JhEYvzBgZgAGOK6+Eq8/tt4BGf/RpiRyOuBQuNUowVFekKwG/nxDHycUxP0A/+Ypc42tVhABvH8733Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Y2yCQMVu; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Y2yCQMVu" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762383544; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XcKXpeoIv1/TaQKBGE1ZFK7wbf9vgDzD2Za3TAGvfaM=; b=Y2yCQMVuM7M3fRc4/lPNcRrfzkGEF/duGONkbpEWwV1iIhPa/iBDnGssq3oIyH4LKxh7BO hp1b5OC38lLTfKRKnEzNcH9BMuxib+hMHUy1t0RBy4292BO6rwo4lxfwQ+fOTNwCRy/WEx K/PzfB19hcbeTw6TI/pkB50wxsI2NjU= Date: Wed, 5 Nov 2025 14:58:48 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v4 2/3] net/smc: bpf: Introduce generic hook for handshake flow To: "D. Wythe" Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, pabeni@redhat.com, song@kernel.org, sdf@google.com, haoluo@google.com, yhs@fb.com, edumazet@google.com, john.fastabend@gmail.com, kpsingh@kernel.org, jolsa@kernel.org, mjambigi@linux.ibm.com, wenjia@linux.ibm.com, wintera@linux.ibm.com, dust.li@linux.alibaba.com, tonylu@linux.alibaba.com, guwen@linux.alibaba.com, bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, sidraya@linux.ibm.com, jaka@linux.ibm.com References: <20251103073124.43077-1-alibuda@linux.alibaba.com> <20251103073124.43077-3-alibuda@linux.alibaba.com> <4450b847-6b31-46f2-bc2d-a8b3197d15c7@linux.dev> <20251105070140.GA31761@j66a10360.sqa.eu95> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20251105070140.GA31761@j66a10360.sqa.eu95> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 11/4/25 11:01 PM, D. Wythe wrote: > On Tue, Nov 04, 2025 at 04:03:46PM -0800, Martin KaFai Lau wrote: >> >> >> On 11/2/25 11:31 PM, D. Wythe wrote: >>> +#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF) >>> +#define smc_call_hsbpf(init_val, sk, func, ...) ({ \ >>> + typeof(init_val) __ret = (init_val); \ >>> + struct smc_hs_ctrl *ctrl; \ >>> + rcu_read_lock(); \ >>> + ctrl = rcu_dereference(sock_net(sk)->smc.hs_ctrl); \ >> >> The smc_hs_ctrl (and its ops) is called from the netns, so the >> bpf_struct_ops is attached to a netns. Attaching bpf_struct_ops to a >> netns has not been done before. More on this later. >> >>> + if (ctrl && ctrl->func) \ >>> + __ret = ctrl->func(__VA_ARGS__); \ >>> + >>> + if (static_branch_unlikely(&tcp_have_smc) && tp->syn_smc) { >>> + tp->syn_smc = !!smc_call_hsbpf(1, sk, syn_option, tp); >> >> ... so just pass tp instead of passing both sk and tp? >> >> [ ... ] >> > > You're right, it is a bit redundant. However, if we merge the parameters, > every user of this macro will be forced to pass tp. In fact, we’re > already considering adding some callback functions that don’t take tp as > a parameter. If the struct_ops callback does not take tp, then don't pass it to the callback. I have a hard time to imagine why the bpf prog will not be interested in the tp/sk pointer though. or you meant the caller does not have tp? and where is the future caller? > > I’ve been considering this: since smc_hs_ctrl is called from the netns, > maybe we should replace the sk parameter with netns directly. After all, > the only reason we pass sk here is to extract sock_net(sk). Doing so > would remove the redundancy and also keep the interface more flexible > for future extensions. What do you think? The net can be obtained from the tp also. Like in this patch, all the caller needs to type "const struct sock *sk = &tp->inet_conn.icsk_inet.sk;". I can imagine all the callers will have to type "sock_net((struct sock *)tp)" if passing net. Why not just do that in the smc_hs_ctrl instead of asking all the callers to type that? I meant something like this (untested): -#define smc_call_hsbpf(init_val, sk, func, ...) ({ \ +#define smc_call_hsbpf(init_val, func, tp, ...) ({ \ typeof(init_val) __ret = (init_val); \ struct smc_hs_ctrl *ctrl; \ rcu_read_lock(); \ - ctrl = rcu_dereference(sock_net(sk)->smc.hs_ctrl); \ + ctrl = rcu_dereference(sock_net((struct sock *)(tp))->smc.hs_ctrl); \ if (ctrl && ctrl->func) \ - __ret = ctrl->func(__VA_ARGS__); \ + __ret = ctrl->func(tp, ##__VA_ARGS__); \ rcu_read_unlock(); \ __ret; \ })