From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v3] Renesas Ethernet AVB driver Date: Wed, 22 Apr 2015 18:18:13 -0400 (EDT) Message-ID: <20150422.181813.1931455043058560592.davem@davemloft.net> References: <553804CA.1030605@cogentembedded.com> <20150422.164242.2185477513394713122.davem@davemloft.net> <553814F0.40405@cogentembedded.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <553814F0.40405@cogentembedded.com> Sender: linux-sh-owner@vger.kernel.org To: sergei.shtylyov@cogentembedded.com Cc: mitsuhiro.kimura.kc@renesas.com, f.fainelli@gmail.com, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, devicetree@vger.kernel.org, galak@codeaurora.org, netdev@vger.kernel.org, richardcochran@gmail.com, linux-sh@vger.kernel.org, masaru.nagai.vx@renesas.com List-Id: devicetree@vger.kernel.org From: Sergei Shtylyov Date: Thu, 23 Apr 2015 00:38:56 +0300 > On 04/22/2015 11:42 PM, David Miller wrote: > >>> Hmm, I've been digging in the net core, and was unable to see where TX >>> skb's get their NET_IP_ALIGN bytes reserved. Have I missed something? >>> Probably need to print out skb's fields... > >> NET_IP_ALIGN is for receive, not transmit. > > But when I print 'skb->data' from the ndo_start_xmit() method (in the > 'sh_eth' driver), all addresses end with 2, so it looks like > NET_IP_ALIGN gets added somewhere... It's the IPV4 header which is 4 byte aligned, then the ethernet header is pushed which is 14 bytes.