From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: [PATCH V4 2/8] netdevice.h: Add a new zerocopy device flag Date: Wed, 04 May 2011 00:55:17 -0700 Message-ID: <1304495717.20660.67.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: Received: from e4.ny.us.ibm.com ([32.97.182.144]:47568 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751850Ab1EDHzV (ORCPT ); Wed, 4 May 2011 03:55:21 -0400 Sender: kvm-owner@vger.kernel.org List-ID: 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 0249fe7..0808f1e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1067,6 +1067,16 @@ struct net_device { #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ #define NETIF_F_RXCSUM (1 << 29) /* Receive checksumming offload */ +/* + * 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