From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: [PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice Date: Mon, 16 May 2011 12:28:48 -0700 Message-ID: <1305574128.3456.23.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: David Miller , mst@redhat.com, Eric Dumazet , Avi Kivity , Arnd Bergmann Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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) + /* Segmentation offload features */ #define NETIF_F_GSO_SHIFT 16 #define NETIF_F_GSO_MASK 0x00ff0000