[RFC][PATCH v6 05/19] Add a function make external buffer owner to query capability.
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From: xiaohui.xin on 21 May 2010 05:30 From: Xin Xiaohui <xiaohui.xin(a)intel.com> The external buffer owner can use the functions to get the capability of the underlying NIC driver. Signed-off-by: Xin Xiaohui <xiaohui.xin(a)intel.com> Signed-off-by: Zhao Yu <yzhaonew(a)gmail.com> Reviewed-by: Jeff Dike <jdike(a)linux.intel.com> --- 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(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |