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 DCB7421D5B0 for ; Wed, 29 Oct 2025 22:38:13 +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=1761777494; cv=none; b=QjSgLw/L8jgZ/EoR8sJnOQ5iT83c6eQhUJfJNUNg6dbxZLfw6CWTsW2Mi+Hb2pcijuM1FptOJzd4rJJLy0TiHSS2ecebcMnA2pImd+eHV88O/lpayK0AAAdXBd6GHu6g4pS4KZ/anIXgRmMYYssO1GzZi1qHDp4Z2bjMf6SOIo0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761777494; c=relaxed/simple; bh=BVskhov3Xg8BYfhlY7/y2ipqSmtxG6yGEuH9tMUeDtI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GyPBieFxHDFmjgU3ArMxd7YXcblWsH2C54mu40Iq9uY/7LU/ps/T+v28KIgXICDo9GLNthjnzx4qvW8+Spco4FaEy4KBZejZiOsDhCOFo83QFYaLj+vFZS7ZucgrDtIBrmBCyCx0wm/HXKMMJb1yGyQDfLHh0Sbq3jvnwkx96Z0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qfVh3pyY; 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="qfVh3pyY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FAB4C4CEF7; Wed, 29 Oct 2025 22:38:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761777493; bh=BVskhov3Xg8BYfhlY7/y2ipqSmtxG6yGEuH9tMUeDtI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qfVh3pyYvwWRZb001lqs6biHuaDkOjAI69YU/OmcEfNitws5PNDLhGC4RnEGdrLCQ tmVJZeFhBJvIfYRrAndGACnDeTeJo0+5NBpWOpUNEzQRrKiAdfIfqlkH5SSrvLQqYb aPMLD8pJoet3kiLP3z1Y0UtyBNXaPGeKob5AJnuvUhck+nCeml09LYOaJ9dTe82D+m aHUX5zjTamltNtYjQPe0eyexMGYjYo+w90BWu793V00vcdi8CDtSs+jqwpTXiM5UMB 69lFnJkqzNKad+ARn14iwS738ZSmW8xRrXuLKcx6+L3uXjLNDMgJRWSgRzgGOV+X/1 9wpKFouZFBOPA== Date: Wed, 29 Oct 2025 15:38:12 -0700 From: Jakub Kicinski To: Vadim Fedorenko Cc: Michal Kubecek , netdev@vger.kernel.org, Kory Maincent Subject: Re: [PATCH ethtool-next] netlink: tsconfig: add HW time stamping configuration Message-ID: <20251029153812.10bd6397@kernel.org> In-Reply-To: <8693b213-2d22-4e47-99bb-5d8ca4f48dd5@linux.dev> References: <20251004202715.9238-1-vadim.fedorenko@linux.dev> <5w25bm7gnbrq4cwtefmunmcylqav524roamuvoz2zv5piadpek@4vpzw533uuyd> <8693b213-2d22-4e47-99bb-5d8ca4f48dd5@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 29 Oct 2025 18:53:20 +0000 Vadim Fedorenko wrote: > >> Well, yes, it's only 1 bit is supposed to be set. Unfortunately, netlink > >> interface was added this way almost a year ago, we cannot change it > >> anymore without breaking user-space API. > > > > The netlink interface only mirrors what we already had in struct > > ethtool_ts_info (i.e. the ioctl interface). Therefore my question was > > not really about this part of kernel API (which is fixed already) but > > rather about the ethtool command line syntax. > > > > In other words, what I really want to ask is: Can we be absolutely sure > > that it can never possibly happen in the future that we might need to > > set more than one bit in a set message? > > > > If the answer is positive, I'm OK with the patch but perhaps we should > > document it explicitly in the TSCONFIG_SET description in kernel file > > Documentation/networking/ethtool-netlink.rst > > Well, I cannot say about long-long future, but for the last decade we > haven't had a need for multiple bits to be set up. I would assume that > the reality will be around the same. > > Jakub/Kory do you have thoughts? hard to prove a negative, is the question leading to a different argument format which will let us set multiple bits? Looks like we could potentially allow specifying tx / rx-filter multiple times? Or invent new keywords for the extra bits which presumably would be somehow orthogonal to filtering? tl;dr I'm unclear on the exact concern..