Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756981Ab0G2LBg (ORCPT ); Thu, 29 Jul 2010 07:01:36 -0400 Received: from mga11.intel.com ([192.55.52.93]:58755 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756903Ab0G2LBW (ORCPT ); Thu, 29 Jul 2010 07:01:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.55,279,1278313200"; d="scan'208";a="590877525" From: xiaohui.xin@intel.com To: netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, mingo@elte.hu, davem@davemloft.net, herbert@gondor.hengli.com.au, jdike@linux.intel.com Cc: Xin Xiaohui Subject: [RFC PATCH v8 04/16] Add a function make external buffer owner to query capability. Date: Thu, 29 Jul 2010 19:14:36 +0800 Message-Id: <1280402088-5849-5-git-send-email-xiaohui.xin@intel.com> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1280402088-5849-4-git-send-email-xiaohui.xin@intel.com> References: <1280402088-5849-1-git-send-email-xiaohui.xin@intel.com> <1280402088-5849-2-git-send-email-xiaohui.xin@intel.com> <1280402088-5849-3-git-send-email-xiaohui.xin@intel.com> <1280402088-5849-4-git-send-email-xiaohui.xin@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2979 Lines: 95 From: Xin Xiaohui The external buffer owner can use the functions to get the capability of the underlying NIC driver. Signed-off-by: Xin Xiaohui Signed-off-by: Zhao Yu Reviewed-by: Jeff Dike --- include/linux/netdevice.h | 2 + net/core/dev.c | 49 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 0 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index aba0308..5f192de 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1599,6 +1599,8 @@ extern gro_result_t napi_frags_finish(struct napi_struct *napi, gro_result_t ret); extern struct sk_buff * napi_frags_skb(struct napi_struct *napi); extern gro_result_t napi_gro_frags(struct napi_struct *napi); +extern int netdev_mp_port_prep(struct net_device *dev, + struct mpassthru_port *port); static inline void napi_free_frags(struct napi_struct *napi) { diff --git a/net/core/dev.c b/net/core/dev.c index 264137f..636f11b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2468,6 +2468,55 @@ void netif_nit_deliver(struct sk_buff *skb) rcu_read_unlock(); } +/* To support meidate passthru(zero-copy) with NIC driver, + * we'd better query NIC driver for the capability it can + * provide, especially for packet split mode, now we only + * query for the header size, and the payload a descriptor + * may carry. If a driver does not use the API to export, + * then we may try to use a default value, currently, + * we use the default value from an IGB driver. Now, + * it's only called by mpassthru device. + */ +#if defined(CONFIG_MEDIATE_PASSTHRU) || defined(CONFIG_MEDIATE_PASSTHRU_MODULE) +int netdev_mp_port_prep(struct net_device *dev, + struct mpassthru_port *port) +{ + int rc; + int npages, data_len; + const struct net_device_ops *ops = dev->netdev_ops; + + if (ops->ndo_mp_port_prep) { + rc = ops->ndo_mp_port_prep(dev, port); + if (rc) + return rc; + } else { + /* If the NIC driver did not report this, + * then we try to use default value. + */ + port->hdr_len = 128; + port->data_len = 2048; + port->npages = 1; + } + + if (port->hdr_len <= 0) + goto err; + + npages = port->npages; + data_len = port->data_len; + if (npages <= 0 || npages > MAX_SKB_FRAGS || + (data_len < PAGE_SIZE * (npages - 1) || + data_len > PAGE_SIZE * npages)) + goto err; + + return 0; +err: + dev_warn(&dev->dev, "invalid page constructor parameters\n"); + + return -EINVAL; +} +EXPORT_SYMBOL(netdev_mp_port_prep); +#endif + /** * netif_receive_skb - process receive buffer from network * @skb: buffer to process -- 1.5.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/