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 306291C9B91; Wed, 2 Oct 2024 17:17:28 +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=1727889449; cv=none; b=NV6Vz/wvbTHk3Wm5AyqVircuEJ9wslbwktwSV49OX+1x6wYo2GfwYFe2X/qBUqYjVyYWXQVAIvncHbg/013AEZwjvNsyIp2YwhgOLy9hLwT1H5dqQ3N9MgCnXbq5vpJjU+UfquDUifc7xAqKLvy6mJrfx2kFJgzeYShp3Y65I6A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727889449; c=relaxed/simple; bh=pfIEXJMb4PrK/x6Ayj1gPI5EQfPIRYz2z5v24LdJmEA=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fAt78LLjBk3qRfU7ikCf7Lgk6ECFWs0J62QHvO0GTBNZAKXL6NEasDJwi3KJQWMAIJDGHlAicZeoXrEX5AHuK9NGRjTNeIyHXrHKjPw3XidKP1M7EVqQKAqKH+5Db1TRqEiQ6EEb9I91BBXNxyXzfux5XnPJqMsXgwSjLu/5TJA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qzEnYJ9C; 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="qzEnYJ9C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 576E4C4CEC2; Wed, 2 Oct 2024 17:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727889448; bh=pfIEXJMb4PrK/x6Ayj1gPI5EQfPIRYz2z5v24LdJmEA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qzEnYJ9CkvJ8iZ4ixy2eyCWweBM9CPz5GeO+p2AgtBUNPETZ6/3NISG/9dC2KI1OY UtwAOkVXxti8ogfSILyF16Jvf/ToKHgA1de0pg7voPLqDgeSkeG77c9u1oVjLXJAk1 DsE2bEBwdFm1/EAo7jhlT/fjOT54ScBLPcmr/RIM0QGWOb2LYpNYLE1lFpV6nBxTAf nv3gBJiehRQNktWr9HRujEXZiH4Tbq3hPaDt9Z2kdwSWcMtVkmQeg7/ngel3QRVNxG F6rGxf6gNyw0cVBru74re6uWB2oBF5dHk9+RNEyIN4zzuY6UvONcoOoRf2fbquNsX5 J7Ud/KXCYedCQ== Date: Wed, 2 Oct 2024 10:17:27 -0700 From: Jakub Kicinski To: Alexander Lobakin , Przemek Kitszel Cc: Joe Damato , netdev@vger.kernel.org, Tony Nguyen , "David S. Miller" , Eric Dumazet , Paolo Abeni , "moderated list:INTEL ETHERNET DRIVERS" , open list , Simon Horman Subject: Re: [RFC net-next 1/1] idpf: Don't hard code napi_struct size Message-ID: <20241002101727.349fc146@kernel.org> In-Reply-To: References: <20240925180017.82891-1-jdamato@fastly.com> <20240925180017.82891-2-jdamato@fastly.com> <6a440baa-fd9b-4d00-a15e-1cdbfce52168@intel.com> <9f86b27c-8d5c-4df9-8d8c-91edb01b0b79@intel.com> 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 Tue, 1 Oct 2024 07:44:36 -0700 Joe Damato wrote: > > But if you change any core API, let's say rename a field used in several > > drivers, you anyway need to adjust the affected drivers. > > Sorry, but that's a totally different argument. > > There are obvious cases where touching certain parts of core would > require changes to drivers, yes. I agree on that if I change an API > or a struct field name, or remove an enum, then this affects drivers > which must be updated. +1 I fully agree with Joe. Drivers asserting the size of core structures is both undue burden on core changes and pointless. The former is subjective, as for the latter: most core structures will contain cold / slow path data, usually at the end. If you care about performance of anything that follows a core struct you need to align the next field yourself. IDK how you want to fit this into your magic macros but complex nested types should be neither ro, rw nor cold. They are separate.