From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) (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 54D284A0C for ; Sat, 25 Jan 2025 02:37:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737772643; cv=none; b=YZpWwRMGRyMKq77PqWgqjCnMKLkTNQaDm9FPVVvy7BSqnMj5yR9E8cA/mPhOuwp918n7nlraZ3EMtSUJ9RNIKZkKvAhGVYKYEnFEab2rrqZY7e776e7lWcHOEi4LjGj1hTFtmteRF4t9rt8/8iMQnoUnKMJTussYkeEOttMKjig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737772643; c=relaxed/simple; bh=/EwTh95JkZoqDpEO1YKgOkQmeAFxmldgcbsp4VFIv9c=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NhIyuBr8FerQ6SlbMKZ2ViONvJmC57vhuL+N7tcSZR6kuSs+pDwdDOG4AdN4UyIOilrqQu405FhhY1+FOx76/6VHJmq8/zBNUdCC7PMCcy+z2VoRap84+99DjWS85Kd8GSwpSh1JRIxK18etjMy0UY4selUP6xbXCPQ8AmNILzM= 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=PgzxJoXf; arc=none smtp.client-ip=91.218.175.184 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="PgzxJoXf" Message-ID: <7bf7110c-b978-45b8-9f74-4a37d6e98d5d@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1737772627; 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=i6iLXzzDkmBVt4OLxXu7H0CDJXdKde9nVZhravGadgs=; b=PgzxJoXfOymHj0LUJvgEiriKiMxP/LQhEMAwLFjTFnHy68tvcH489/B5TKs9cDg6ee21uV xKPS5uskwq/rxbrF8QMX8zOIfhKYzq0jVAFgMnazh9aUrq2KnTFhnWWHBdZZExrmyPvNzg zhIjEwUCPMc+SdA40hsV3KkM/zXvRkE= Date: Fri, 24 Jan 2025 18:36:54 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [RFC PATCH net-next v6 08/13] net-timestamp: support hw SCM_TSTAMP_SND for bpf extension To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, horms@kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org References: <20250121012901.87763-1-kerneljasonxing@gmail.com> <20250121012901.87763-9-kerneljasonxing@gmail.com> <40e2a7d8-dcba-4dfe-8c4d-14d8cf4954cf@linux.dev> <3a91d654-0e61-4da0-9d09-66a82a24012a@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 1/24/25 5:35 PM, Jason Xing wrote: > On Sat, Jan 25, 2025 at 9:30 AM Martin KaFai Lau wrote: >> >> On 1/24/25 5:18 PM, Jason Xing wrote: >>>>> @@ -5577,9 +5578,9 @@ static void skb_tstamp_tx_bpf(struct sk_buff *skb, struct sock *sk, >>>>> op = BPF_SOCK_OPS_TS_SCHED_OPT_CB; >>>>> break; >>>>> case SCM_TSTAMP_SND: >>>>> + op = sw ? BPF_SOCK_OPS_TS_SW_OPT_CB : BPF_SOCK_OPS_TS_HW_OPT_CB; >>>>> if (!sw) >>>>> - return; >>>>> - op = BPF_SOCK_OPS_TS_SW_OPT_CB; >>>>> + *skb_hwtstamps(skb) = *hwtstamps; >>>> hwtstamps may still be NULL, no? >>> Right, it can be zero if something wrong happens. >> >> Then it needs a NULL check, no? > > My original intention is passing whatever to the userspace, so the bpf > program will be aware of what is happening in the kernel. This is fine. > Passing NULL to hwstamps is right which will not cause any problem, I think. > > Do you mean the default value of hwstamps itself is NULL so in this > case we don't need to re-init it to NULL again? > > Like this: > If (*hwtstamps) if (hwtstamps) instead ? I don't know. If hwtstamps is NULL, doing *hwtstamps will be bad and oops.... May be my brain doesn't work well at the end of Friday. Please check. > *skb_hwtstamps(skb) = *hwtstamps; > > But it looks no different actually. > > Thanks, > Jason