From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 0/3] net: macb: add pad and fcs support Date: Tue, 07 Aug 2018 13:19:09 -0700 (PDT) Message-ID: <20180807.131909.2224882167750246331.davem@davemloft.net> References: <1533633914-30264-1-git-send-email-claudiu.beznea@microchip.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: nicolas.ferre@microchip.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, harinik@xilinx.com, jennifer.dahm@ni.com, nathan.sullivan@ni.com, rafalo@cadence.com, harinikatakamlinux@gmail.com To: claudiu.beznea@microchip.com Return-path: In-Reply-To: <1533633914-30264-1-git-send-email-claudiu.beznea@microchip.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Claudiu Beznea Date: Tue, 7 Aug 2018 12:25:11 +0300 > In [1] it was reported that UDP checksum is offloaded to hardware no mather > it was previously computed in software or not. The proposal on [1] was to > disable TX checksum offload. > > This series (mostly patch 3/3) address the issue described at [1] by > setting NOCRC bit to TX buffer descriptor for SKBs that arrived from > networking stack with checksum computed. For these packets padding and FCS > need to be added (hardware doesn't compute them if NOCRC bit is set). The > minimum packet size that hardware expects is 64 bytes (including FCS). > This feature could not be used in case of GSO, so, it was used only for > no GSO SKBs. > > For SKBs wich requires padding and FCS computation macb_pad_and_fcs() > checks if there is enough headroom and tailroom in SKB to avoid copying > SKB structure. Since macb_pad_and_fcs() may change SKB the > macb_pad_and_fcs() was places in macb_start_xmit() b/w macb_csum_clear() > and skb_headlen() calls. > > This patch was tested with pktgen in kernel tool in a script like this: > (pktgen_sample01_simple.sh is at [2]): ... Series applied to net-next, thanks.