netdev - Re: [PATCH net-next 04/12] net: sched: flower: track filter deletion with flag

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Date:   Thu, 14 Feb 2019 21:49:26 +0100
From:   Stefano Brivio <sbrivio@...hat.com>
To:     Vlad Buslov <vladbu@...lanox.com>
Cc:     netdev@...r.kernel.org, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jiri@...nulli.us, davem@...emloft.net
Subject: Re: [PATCH net-next 04/12] net: sched: flower: track filter
 deletion with flag

On Thu, 14 Feb 2019 09:47:04 +0200
Vlad Buslov <vladbu@...lanox.com> wrote:

> +static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f,
> +		       bool *last, struct netlink_ext_ack *extack)

This would be easier to follow (at least for me):

>  {
>  	struct cls_fl_head *head = fl_head_dereference(tp);
>  	bool async = tcf_exts_get_net(&f->exts);
> -	bool last;
> -
> -	idr_remove(&head->handle_idr, f->handle);
> -	list_del_rcu(&f->list);
> -	last = fl_mask_put(head, f->mask, async);
> -	if (!tc_skip_hw(f->flags))
> -		fl_hw_destroy_filter(tp, f, extack);
> -	tcf_unbind_filter(tp, &f->res);
> -	__fl_put(f);
> +	int err = 0;

without this

> +
> +	(*last) = false;

with *last = false;

> +
> +	if (!f->deleted) {

with:
	if (f->deleted)
		return -ENOENT;

> +		f->deleted = true;
> +		rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
> +				       f->mask->filter_ht_params);
> +		idr_remove(&head->handle_idr, f->handle);
> +		list_del_rcu(&f->list);
> +		(*last) = fl_mask_put(head, f->mask, async);

with:
	*last = fl_mask_put(head, f->mask, async);

> +		if (!tc_skip_hw(f->flags))
> +			fl_hw_destroy_filter(tp, f, extack);
> +		tcf_unbind_filter(tp, &f->res);
> +		__fl_put(f);

and a return 0; here

> +	} else {
> +		err = -ENOENT;
> +	}
>  
> -	return last;
> +	return err;
>  }
>  
> [...]
>
> @@ -1520,14 +1541,14 @@ static int fl_delete(struct tcf_proto *tp, void *arg, bool *last,
>  {
>  	struct cls_fl_head *head = fl_head_dereference(tp);
>  	struct cls_fl_filter *f = arg;
> +	bool last_on_mask;

This is unused in this series, maybe change __fl_delete() to optionally
take NULL as 'bool *last' argument?

> +	int err = 0;

Nit: no need to initialise this.
 
> -	rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
> -			       f->mask->filter_ht_params);
> -	__fl_delete(tp, f, extack);
> +	err = __fl_delete(tp, f, &last_on_mask, extack);
>  	*last = list_empty(&head->masks);
>  	__fl_put(f);
>  
> -	return 0;
> +	return err;
>  }
>  
>  static void fl_walk(struct tcf_proto *tp, struct tcf_walker *arg,

-- 
Stefano