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 A4D89202997; Sat, 17 Jan 2026 17:15:45 +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=1768670145; cv=none; b=OMouLzf5gXWer2BF8tT1W1X7YRjDkOmW3uB2vKAgh5YAZ+MfgLR+icymRK9VwmYp4alCfTqs3xXy7EoJG+Y3YYISuIssBdhz5gtburz6jKqt23x9odEWpjPNdY3zgHvo3YnFbDlG/XAS5cyEPtWRZwES32kYyJOq/XV0D5rGG3A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768670145; c=relaxed/simple; bh=jGr49H7lELR3ftr7XRFa0Z5/p9+HvUSv+Xd//G6J90g=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GInulXTDounV48/u3QbtKkbq0oPIumI3D0Q+eygpAIYALYjUtmpKnBnWGo4oe3esM43hmy5ZgtS/4Giy6kMzCBrmg82VlLluRJzXb5KhGVc4UUCKaWHFqT6MukNVIgE/eYt+jIYYHjKR7z++KErQehovpDBH2aHD8YCyWgZY+o4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XpgrzVGB; 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="XpgrzVGB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8E01C4CEF7; Sat, 17 Jan 2026 17:15:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768670145; bh=jGr49H7lELR3ftr7XRFa0Z5/p9+HvUSv+Xd//G6J90g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XpgrzVGBnnizfBHo6er1szMgiQGOEY2Ws1cA5Qfl875qIUz7a/6RHGXXuXlC7ChtO l2QLfsN/7lwDEoRma+kg9TMDF61qzmvOmHnJMdT7AEtm5+EPpY+hn2N6TDq7Im+LVM lRDBnfWeZLkVqiEBqI1CTXkVJ/bjqAUIjeMNXP9u7YP5pNF0BjqsEfwcel1sBn6L/v FQNE8+CJ25/ygqxCOnX+UZWb3hxItRMkldGzoGxnh83XDt3KJOrg68CRdyH/0u1u4k elhTxv9D3Jt7uY9lrevhn7V7SY6V84GVYc/fb0uQ1FRNMS0DrElotqLReRt+U+6hT3 e4/X9Nkqv/APA== Date: Sat, 17 Jan 2026 09:15:43 -0800 From: Jakub Kicinski To: Oliver Hartkopp Cc: Paolo Abeni , linux-can@vger.kernel.org, Marc Kleine-Budde , Vincent Mailhol , netdev@vger.kernel.org, Eric Dumazet , Simon Horman , davem@davemloft.net Subject: Re: [can-next 0/5] can: remove private skb headroom infrastructure Message-ID: <20260117091543.7881db1a@kernel.org> In-Reply-To: References: <20260112150908.5815-1-socketcan@hartkopp.net> 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 Fri, 16 Jan 2026 11:31:14 +0100 Oliver Hartkopp wrote: > Long story short: Using the common pattern to wrap a union around > dual-usable skb space is the most efficient and least risky solution IMHO. The concern is that we're making a precedent for, let's call it - not-routable-networking technology to redefine fields in skb that it doesn't need. From the maintainability perspective that's a big risk, IMHO. I fully acknowledge tho that using md dst will be a lot more work. Which makes this situation an unpleasant judgment call :(