From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH 1/1] TX throttling bug-fixing patch of AX88179_178A Date: Mon, 22 Jul 2013 18:11:15 +0100 Message-ID: <1374513075.1635.14.camel@bwh-desktop.uk.level5networks.com> References: <1374311809-4155-1-git-send-email-freddy@asix.com.tw> <1374512879.4990.19.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , , , , , , , To: Eric Dumazet Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:10437 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757398Ab3GVRLT (ORCPT ); Mon, 22 Jul 2013 13:11:19 -0400 In-Reply-To: <1374512879.4990.19.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2013-07-22 at 10:07 -0700, Eric Dumazet wrote: > On Sat, 2013-07-20 at 17:16 +0800, freddy@asix.com.tw wrote: > > From: Freddy Xin > > > > Disable TSO and SG network features in reset() and bind() functions, > > and check the return value of skb_linearize() in tx_fixup() to prevent > > TX throttling. > > > > Signed-off-by: Freddy Xin > > --- > > drivers/net/usb/ax88179_178a.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c > > index 1e3c302..eb71331 100644 > > --- a/drivers/net/usb/ax88179_178a.c > > +++ b/drivers/net/usb/ax88179_178a.c > > @@ -1029,7 +1029,7 @@ static int ax88179_bind(struct usbnet *dev, struct usb_interface *intf) > > dev->mii.supports_gmii = 1; > > > > dev->net->features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | > > - NETIF_F_RXCSUM | NETIF_F_SG | NETIF_F_TSO; > > + NETIF_F_RXCSUM; > > > > dev->net->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | > > NETIF_F_RXCSUM | NETIF_F_SG | NETIF_F_TSO; > > @@ -1173,7 +1173,9 @@ ax88179_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) > > if (((skb->len + 8) % frame_size) == 0) > > tx_hdr2 |= 0x80008000; /* Enable padding */ > > > > - skb_linearize(skb); > > + if (skb_linearize(skb)) > > + return NULL; > > + > > > > I guess that if a driver does not advertise NETIF_F_SG, this > skb_linearize() call is not needed : All frames reaching your xmit > function should already be linear Look at the hw_features initialisation... Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.