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 14C9A33A007; Thu, 2 Apr 2026 15:37:49 +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=1775144270; cv=none; b=UdovXm6J7Wl3EY38MA5e1+BNrJnc4Im7U1Bnn6eryhEAvNFfzpBpcKyQaGvM9WRaCBMZ+yOse0YpkRuGlJoOlgJTOwsbWHEn0R9lZ1j3NWk/Bu/3EW2nJlu+QKD9b2DwW8ZlIBElRT8XwOKpfttxPO4OTU8KcSEfeOehvMhhfK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775144270; c=relaxed/simple; bh=ohZ2HDtp4Z/Z6WJrkpeUxDLSzAUSROOullIzOzd8hmY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jfMYYj8kanDE3TmTHi0aXblBbFqTqoZIX0PgmkZy/IHzwCpjtfAOVXfcL61B46b1Rqf47lMkrq5jToRc+NFXtB8rKLrT3jjho6DxZYOIZKTy1eeaNWa0BP9WKQMc58dWQatfDrsfjzNfaYU5AJF0/U2vL7dQtKY6UHXOjgLREHw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D392ZXZS; 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="D392ZXZS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E81EAC116C6; Thu, 2 Apr 2026 15:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775144269; bh=ohZ2HDtp4Z/Z6WJrkpeUxDLSzAUSROOullIzOzd8hmY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=D392ZXZSh4jR48UCxYhNi9SeatNR+FbXthOJM98LYHxJS9/Q6CONIEPD74QcqMxQa EP1c6Pistguv12W1E7eSJMU7joPtxbgo/dcwshmT3/9oPnicJ4D3slH5e+RYqBfu5L RApvGw0q/8xSqB3md7/+O/g75ejuU5M7szSbBuiZeLs4QM+lXnYPELyuMaWIpzVS60 81KIfgxKH1k3mxUyJ7VQyyMJkCEuMxkQ71KMHPgkgPRATCEN1QU9KzEUVsXRPHvf0D aqa2DCPNmhvLAotVQTPrGaMNAGjY4uF5yCQBrMbJiuYnhTJ0Z0GooBanRADjFJWqRi Tb4uru2vjG0Zg== Date: Thu, 2 Apr 2026 08:37:47 -0700 From: Jakub Kicinski To: Vladimir Oltean Cc: netdev@vger.kernel.org, Zefir Kurtisi , Claudiu Manoil , Wei Fang , Clark Wang , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Ioana Ciornei , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , Simon Horman , bpf@vger.kernel.org, imx@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH net 2/3] net: enetc: pad short frames in software Message-ID: <20260402083747.4f496c9a@kernel.org> In-Reply-To: <20260401172246.1075883-3-vladimir.oltean@nxp.com> References: <20260401172246.1075883-1-vladimir.oltean@nxp.com> <20260401172246.1075883-3-vladimir.oltean@nxp.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 Wed, 1 Apr 2026 20:22:45 +0300 Vladimir Oltean wrote: > The ENETC does not support BUF_LEN or FRM_LEN in TX buffer descriptors > less than 16. This is written in the reference manual of all SoCs > supported by the driver: LS1028A, i.MX943, i.MX95 etc. > > Frames must not have a FRM_LEN that is less than 16 bytes. Frames of > 0-15 bytes are not supported. > (...) > The first descriptor in a chain must not have a BUFF_LEN that is less > than 16 bytes. > > I don't think proper attention was paid to this during development, we > found the text at the end of a bug investigation. Therefore, the driver > does not enforce this. AI points out that the frame may be longer than 16B but fragmented. Only the Ethernet header is guaranteed to be in the linear part. So you may need to also toss something like pskb_may_pull(16) after that padding call. -- pw-bot: cr