Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933167Ab0FEKMc (ORCPT ); Sat, 5 Jun 2010 06:12:32 -0400 Received: from mga01.intel.com ([192.55.52.88]:50025 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932829Ab0FEKHA (ORCPT ); Sat, 5 Jun 2010 06:07:00 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,366,1272870000"; d="scan'208";a="804988032" 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 v7 05/19] Add a function make external buffer owner to query capability. Date: Sat, 5 Jun 2010 18:14:44 +0800 Message-Id: <1275732899-5423-5-git-send-email-xiaohui.xin@intel.com> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1275732899-5423-4-git-send-email-xiaohui.xin@intel.com> References: <1275732899-5423-1-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-2-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-3-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-4-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: 3011 Lines: 96 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 | 51 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+), 0 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 183c786..31d9c4a 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1599,6 +1599,8 @@ extern gro_result_t napi_gro_frags(struct napi_struct *napi); extern int netdev_mp_port_attach(struct net_device *dev, struct mpassthru_port *port); extern void netdev_mp_port_detach(struct net_device *dev); +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 ecbb6b1..37b389a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2497,6 +2497,57 @@ void netdev_mp_port_detach(struct net_device *dev) } EXPORT_SYMBOL(netdev_mp_port_detach); +/* 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; + + /* needed by packet split */ + + 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/