Subject: Re: [net-next PATCH v4 06/10] netdev-genl: Add netlink framework functions for napi

From: Jakub Kicinski <[email-masked]>
Date: Tue, 10 Oct 2023 19:29:26 -0700

On Fri, 06 Oct 2023 02:15:10 -0700 Amritha Nambiar wrote:
> Implement the netdev netlink framework functions for
> napi support. The netdev structure tracks all the napi
> instances and napi fields. The napi instances and associated
> parameters can be retrieved this way.
> 
> Signed-off-by: Amritha Nambiar <[email-masked]>
> Reviewed-by: Sridhar Samudrala <[email-masked]>
> ---
>  include/linux/netdevice.h |    2 +
>  net/core/dev.c            |    4 +-
>  net/core/netdev-genl.c    |  117 ++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 119 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 264ae0bdabe8..da211f4d81db 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -536,6 +536,8 @@ static inline bool napi_complete(struct napi_struct *n)
>  	return napi_complete_done(n, 0);
>  }
>  
> +struct napi_struct *napi_by_id(unsigned int napi_id);

this can go into net/core/dev.h ?

>  int dev_set_threaded(struct net_device *dev, bool threaded);
>  
>  /**

> @@ -6144,6 +6143,7 @@ static struct napi_struct *napi_by_id(unsigned int napi_id)
>  
>  	return NULL;
>  }
> +EXPORT_SYMBOL(napi_by_id);

Why is it exported? Exports are for use in modules.

>  int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
>  {
> -	return -EOPNOTSUPP;
> +	struct napi_struct *napi;
> +	struct sk_buff *rsp;
> +	u32 napi_id;
> +	int err;
> +
> +	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_NAPI_NAPI_ID))
> +		return -EINVAL;
> +
> +	napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_NAPI_ID]);
> +
> +	rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> +	if (!rsp)
> +		return -ENOMEM;
> +
> +	rcu_read_lock();
> +
> +	napi = napi_by_id(napi_id);
> +	if (napi)
> +		err  = netdev_nl_napi_fill_one(rsp, napi, info);

double space

> +	else
> +		err = -EINVAL;