Re: [RFC PATCH v7 03/19] Export 2 func for device to assign/deassign new strucure

Eric Dumazet
2010-06-05T14:51:36Z

Le samedi 05 juin 2010 à 18:14 +0800, xiaohui.xin@intel.com a écrit :
> From: Xin Xiaohui <xiaohui.xin@intel.com>
>
> Signed-off-by: Xin Xiaohui <xiaohui.xin@intel.com>
> Signed-off-by: Zhao Yu <yzhao81new@gmail.com>
> Reviewed-by: Jeff Dike <jdike@linux.intel.com>
> ---
> include/linux/netdevice.h | 3 +++
> net/core/dev.c | 28 ++++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index bae725c..efb575a 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -1592,6 +1592,9 @@ 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_attach(struct net_device *dev,
> + struct mpassthru_port *port);
> +extern void netdev_mp_port_detach(struct net_device *dev);
>
> static inline void napi_free_frags(struct napi_struct *napi)
> {
> diff --git a/net/core/dev.c b/net/core/dev.c
> index f769098..ecbb6b1 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2469,6 +2469,34 @@ void netif_nit_deliver(struct sk_buff *skb)
> rcu_read_unlock();
> }
>
> +/* Export two functions to assign/de-assign mp_port pointer
> + * to a net device.
> + */
> +
> +int netdev_mp_port_attach(struct net_device *dev,
> + struct mpassthru_port *port)
> +{
> + /* locked by mp_mutex */
> + if (rcu_dereference(dev->mp_port))
> + return -EBUSY;
> +

Please... this is bogus...

Try with following config settings :

CONFIG_PROVE_LOCKING=y
CONFIG_PROVE_RCU=y
CONFIG_PROVE_RCU_REPEATEDLY=y

> + rcu_assign_pointer(dev->mp_port, port);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(netdev_mp_port_attach);
> +
> +void netdev_mp_port_detach(struct net_device *dev)
> +{
> + /* locked by mp_mutex */
> + if (!rcu_dereference(dev->mp_port))
> + return;

same problem here

> +
> + rcu_assign_pointer(dev->mp_port, NULL);
> + synchronize_rcu();
> +}
> +EXPORT_SYMBOL(netdev_mp_port_detach);
> +
> /**
> * netif_receive_skb - process receive buffer from network
> * @skb: buffer to process