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 4A74931355C; Thu, 29 Jan 2026 01:41:38 +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=1769650899; cv=none; b=DJQM5qq0bamJgFyw/wDIyrYedU1rx+STH/l420NwojitOZUV6b/JlDs8SAh9HjBOCkqnpX3UEEPzxVcdJN4Ve5YFK3oC8mm2ei1r7O1rYPy7/g4cDh6+3X3aw3lk80jLVFK9xWIzbERNs4hNF0ZrMJy3MhNYFh62DP5t/XcF7is= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769650899; c=relaxed/simple; bh=xDPqYiZQa7TzJ8mSUu1DL8UHnEMsE1fthjzDfHVLDyM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FuHr7ThiZDuw5FFmReiDgUwK4hurWDiIBKP9FL1QBJrjq5Ers25JMketqQvSstiNfYogWnOObYxV9cmSiV9pdwzxkrsUBrKoWExkzlUhtdEO5M29UZn3yISJV7Len6Uef2EHKWwUC8vLZRBsJDXR0DqvntsyFZpXcmGUVie+e+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TGyD6dSg; 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="TGyD6dSg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B69CC4CEF1; Thu, 29 Jan 2026 01:41:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769650898; bh=xDPqYiZQa7TzJ8mSUu1DL8UHnEMsE1fthjzDfHVLDyM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TGyD6dSgfJMlRuEck/YRbTZmCy35V0telRLezAySciRZ5rsNPqR35Up8zki6spQOw IiS4pBSdiXieVP/hdt22dsaSfhcOCgOKfY2fJO8M1WVfOqElpWJc7u/0BoCSJA9yv/ Z+ZUu35lE4sen/mze4yJTKtssVd3WdgAQSacJOWUKVXf7N7eyB3Ypvb6MzjkiPwQlv hx7aKfC21j9UnAr6gFY9zEBWsYJqLqU/Q6xqq92j5ZgbAhMLpIqLOEBK1yqmlIcgjj N/aJFAJZtanTKpr90zPSy9P7tf8AYiyA0ZPvT37XNY4mAxiHi9Gkt+kM0eCkBwQCCS K//SiJb5Cuk+Q== Date: Wed, 28 Jan 2026 17:41:37 -0800 From: Jakub Kicinski To: Oliver Hartkopp via B4 Relay Cc: socketcan@hartkopp.net, netdev@vger.kernel.org, linux-can@vger.kernel.org, Marc Kleine-Budde Subject: Re: [PATCH net-next v4 0/6] move CAN skb headroom content to skb extensions Message-ID: <20260128174137.65929694@kernel.org> In-Reply-To: <20260128-can_skb_ext-v1-0-330f60fd5d7e@hartkopp.net> References: <20260128-can_skb_ext-v1-0-330f60fd5d7e@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 Wed, 28 Jan 2026 23:43:39 +0100 Oliver Hartkopp via B4 Relay wrote: > CAN bus related skbuffs (ETH_P_CAN/ETH_P_CANFD/ETH_P_CANXL) simply contain > CAN frame structs for CAN CC/FD/XL of skb->len length at skb->data. Those > CAN skbs do not have network/mac/transport headers nor other such > references for encapsulated protocols like ethernet/IP protocols. > > To store data for CAN specific use-cases all CAN bus related skbuffs are > created with a 16 byte private skb headroom (struct can_skb_priv). Using > the skb headroom and accessing skb->head for this private data led to > several problems in the past likely due to "The struct can_skb_priv > business is highly unconventional for the networking stack." [1] > > This patch set aims to remove the unconventional skb headroom usage for CAN > bus related skbuffs and use the common skb extensions instead. If you're targeting netdev trees please comply with our community guidelines: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html -- pv-bot: 24h