From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joseph Gasparakis Subject: Re: [PATCH v3 1/4] net: Add support for hardware-offloaded encapsulation Date: Fri, 7 Dec 2012 11:52:43 -0800 (PST) Message-ID: References: <20121207.142845.1145515122357569641.davem@davemloft.net> <20121207.143725.1501926484331042018.davem@davemloft.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: joseph.gasparakis@intel.com, bhutchings@solarflare.com, alexander.h.duyck@intel.com, shemminger@vyatta.com, chrisw@sous-sol.org, gospo@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dmitry@broadcom.com, saeed.bishara@gmail.com, peter.p.waskiewicz.jr@intel.com To: David Miller Return-path: In-Reply-To: <20121207.143725.1501926484331042018.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, 7 Dec 2012, David Miller wrote: > From: Joseph Gasparakis > Date: Fri, 7 Dec 2012 11:41:46 -0800 (PST) > > > > > > > On Fri, 7 Dec 2012, David Miller wrote: > > > >> From: Joseph Gasparakis > >> Date: Fri, 7 Dec 2012 10:24:17 -0800 (PST) > >> > >> > So the idea here is that the driver will use the headers for checksumming > >> > if the skb->encapsulation bit is on. The bit should be set in the protocol > >> > driver. > >> > > >> > To answer the second comment, the flags that we use in this series of > >> > patches is NETIF_F_IP_CSUM, NETIF_F_IPV6_CSUM and NETIF_F_SG. These are > >> > the bits that we propose will be used for checksumming of encapsulation. > >> > As per a previous comment in v2, the hw_enc_features field should be used > >> > also in the future when NICs have more encap offloads, so one could > >> > indicate these features there from the driver. > >> > > >> > Furthermore, I submitted a patch for Rx checksumming, where NETIF_F_RXCSUM > >> > is used, again in conjunction with skb->encapsulation flag. As I mention > >> > in my logs, the driver is expected to set the ip_summed to UNNECESSARY and > >> > turn the skb->encapsulation on, to indicate that the inner headers are > >> > already HW checksummed. > >> > > >> > >> This is the kind of language that belongs in the commit message and > >> code comments. > >> > > Sure. I'll wait to gather some more feedback if there is any and I will > > re-spin this off adding more code comments and clarify this in the logs. > > Great. > > Please note that this request applies to your receive side change too. > I believe the logs are sufficient in the rx patch: This patch adds capability in vxlan to identify received checksummed inner packets and signal them to the upper layers of the stack. The driver needs to set the skb->encapsulation bit and also set the skb->ip_summed to CHECKSUM_UNNECESSARY. ...but I can add more comments to the code if this is what you are referring to.