From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice Date: Mon, 16 May 2011 20:35:18 +0100 Message-ID: <1305574518.2885.25.camel@bwh-desktop> References: <1305574128.3456.23.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , mst@redhat.com, Eric Dumazet , Avi Kivity , Arnd Bergmann , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Shirley Ma Return-path: In-Reply-To: <1305574128.3456.23.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Mon, 2011-05-16 at 12:28 -0700, Shirley Ma wrote: > Signed-off-by: Shirley Ma > --- > > include/linux/netdevice.h | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index a134d80..2646251 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1066,6 +1066,16 @@ struct net_device { > #define NETIF_F_NOCACHE_COPY (1 << 30) /* Use no-cache copyfromuser */ > #define NETIF_F_LOOPBACK (1 << 31) /* Enable loopback */ > > +/* > + * Bit 31 is for device to map userspace buffers -- zerocopy > + * Device can set this flag when it supports HIGHDMA. > + * Device can't recycle this kind of skb buffers. > + * There are 256 bytes copied, the rest of buffers are mapped. > + * The userspace callback should only be called when last reference to this skb > + * is gone. > + */ > +#define NETIF_F_ZEROCOPY (1 << 31) Sorry, bit 31 is taken. You get the job of turning features into a wider bitmap. Ben. -- Ben Hutchings, Senior Software 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.