[Devel] Re: [NETFILTER] early_drop() imrovement (v4)

[Vasily Averin]

Patrick McHardy wrote:
> Vasily Averin wrote:
>> Patrick McHardy wrote:
> -static int early_drop(struct hlist_head *chain)
> +static int early_drop(unsigned int hash)
>  {
>  	/* Use oldest entry, which is roughly LRU */
>  	struct nf_conntrack_tuple_hash *h;
>  	struct nf_conn *ct = NULL, *tmp;
>  	struct hlist_node *n;
> -	int dropped = 0;
> +	unsigned int i;
> +	int dropped = 0, cnt = NF_CT_EVICTION_RANGE;
>  
>  	read_lock_bh(&nf_conntrack_lock);
> -	hlist_for_each_entry(h, n, chain, hnode) {
> -		tmp = nf_ct_tuplehash_to_ctrack(h);
> -		if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
> -			ct = tmp;
> +	for (i = 0; i < nf_conntrack_htable_size; i++) {
> +		hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
> +			tmp = nf_ct_tuplehash_to_ctrack(h);
> +			if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
> +				ct = tmp;

It is incorrect: you should break nested loop here too.

> +			if (--cnt <= 0)
> +				goto stop;
> +		}
> +		if (ct)
> +			break;
> +		hash = (hash + 1) & (nf_conntrack_htable_size - 1);
>  	}
> +stop:
>  	if (ct)
>  		atomic_inc(&ct->ct_general.use);
>  	read_unlock_bh(&nf_conntrack_lock);