From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian King Subject: Re: [PATCH 2/6] ibmveth: Implement ethtool hooks to enable/disable checksum offload Date: Tue, 07 Aug 2007 17:07:12 -0500 Message-ID: <46B8ED10.1060701@linux.vnet.ibm.com> References: <11864293333377-patch-mail.ibm.com> <200708061942.l76JgLrU009242@d01av04.pok.ibm.com> <46B8E891.80403@garzik.org> Reply-To: brking@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linuxppc-dev@ozlabs.org, rcjenn@linux.vnet.ibm.com, santil@linux.vnet.ibm.com, netdev@vger.kernel.org To: Jeff Garzik Return-path: In-Reply-To: <46B8E891.80403@garzik.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+glppd-linuxppc64-dev=m.gmane.org@ozlabs.org Errors-To: linuxppc-dev-bounces+glppd-linuxppc64-dev=m.gmane.org@ozlabs.org List-Id: netdev.vger.kernel.org Jeff Garzik wrote: > Brian King wrote: >> This patch adds the appropriate ethtool hooks to allow for enabling/disabling >> of hypervisor assisted checksum offload for TCP. >> >> Signed-off-by: Brian King >> --- >> >> linux-2.6-bjking1/drivers/net/ibmveth.c | 118 +++++++++++++++++++++++++++++++- >> linux-2.6-bjking1/drivers/net/ibmveth.h | 1 >> 2 files changed, 117 insertions(+), 2 deletions(-) >> >> diff -puN drivers/net/ibmveth.c~ibmveth_csum_offload_ethtool drivers/net/ibmveth.c >> --- linux-2.6/drivers/net/ibmveth.c~ibmveth_csum_offload_ethtool 2007-08-01 14:55:14.000000000 -0500 >> +++ linux-2.6-bjking1/drivers/net/ibmveth.c 2007-08-01 14:55:14.000000000 -0500 >> @@ -641,12 +641,125 @@ static u32 netdev_get_link(struct net_de >> return 1; >> } >> >> +static void ibmveth_set_rx_csum_flags(struct net_device *dev, u32 data) >> +{ >> + struct ibmveth_adapter *adapter = dev->priv; >> + >> + if (data) >> + adapter->rx_csum = 1; >> + else { >> + adapter->rx_csum = 0; >> + dev->features &= ~NETIF_F_IP_CSUM; > > why does this RX-related code clear a TX-related flag? Its related to how the pSeries firmware works. The firmware provides an interface to enable "checksum offload", which means both tx and rx checksum offload from the firmware's point of view. The firmware does not support enabling checksum offload for only rx. If I disable it for rx I have to disable it for tx as well, otherwise the firmware will reject all future tx buffers I throw at it that are not checksummed. -Brian -- Brian King Linux on Power Virtualization IBM Linux Technology Center