Re: [PATCH v3 05/11] net: sched: implement action API that deletes action by index

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Mon, May 28, 2018 at 12:17:23AM +0300, Vlad Buslov wrote:
> Implement new action API function that atomically finds and deletes action
> from idr by index. Intended to be used by lockless actions that do not rely
> on rtnl lock.
> 
> Signed-off-by: Vlad Buslov <vladbu@mellanox.com>

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
> Changes from V1 to V2:
> - Rename tcf_idr_find_delete to tcf_idr_delete_index.
> 
>  include/net/act_api.h |  1 +
>  net/sched/act_api.c   | 39 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/include/net/act_api.h b/include/net/act_api.h
> index 888ff471bbf6..d94ec6400673 100644
> --- a/include/net/act_api.h
> +++ b/include/net/act_api.h
> @@ -153,6 +153,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
>  		   int bind, bool cpustats);
>  void tcf_idr_insert(struct tc_action_net *tn, struct tc_action *a);
>  
> +int tcf_idr_delete_index(struct tc_action_net *tn, u32 index);
>  int __tcf_idr_release(struct tc_action *a, bool bind, bool strict);
>  
>  static inline int tcf_idr_release(struct tc_action *a, bool bind)
> diff --git a/net/sched/act_api.c b/net/sched/act_api.c
> index aa304d36fee0..0f31f09946ab 100644
> --- a/net/sched/act_api.c
> +++ b/net/sched/act_api.c
> @@ -319,6 +319,45 @@ bool tcf_idr_check(struct tc_action_net *tn, u32 index, struct tc_action **a,
>  }
>  EXPORT_SYMBOL(tcf_idr_check);
>  
> +int tcf_idr_delete_index(struct tc_action_net *tn, u32 index)
> +{
> +	struct tcf_idrinfo *idrinfo = tn->idrinfo;
> +	struct tc_action *p;
> +	int ret = 0;
> +
> +	spin_lock(&idrinfo->lock);
> +	p = idr_find(&idrinfo->action_idr, index);
> +	if (!p) {
> +		spin_unlock(&idrinfo->lock);
> +		return -ENOENT;
> +	}
> +
> +	if (!atomic_read(&p->tcfa_bindcnt)) {
> +		if (refcount_dec_and_test(&p->tcfa_refcnt)) {
> +			struct module *owner = p->ops->owner;
> +
> +			WARN_ON(p != idr_remove(&idrinfo->action_idr,
> +						p->tcfa_index));
> +			spin_unlock(&idrinfo->lock);
> +
> +			if (p->ops->cleanup)
> +				p->ops->cleanup(p);
> +
> +			gen_kill_estimator(&p->tcfa_rate_est);
> +			free_tcf(p);
> +			module_put(owner);
> +			return 0;
> +		}
> +		ret = 0;
> +	} else {
> +		ret = -EPERM;
> +	}
> +
> +	spin_unlock(&idrinfo->lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL(tcf_idr_delete_index);
> +
>  int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
>  		   struct tc_action **a, const struct tc_action_ops *ops,
>  		   int bind, bool cpustats)
> -- 
> 2.7.5
>