Subject: Re: [net-next PATCH 1/2] fib_trie: Fix warning on fib4_rules_exit

From: Alexander Duyck <[email-masked]>
Date: Fri, 27 Mar 2015 16:29:18 -0700

On 03/27/2015 03:14 PM, Cong Wang wrote:
> On Fri, Mar 27, 2015 at 2:14 PM, Alexander Duyck
> <[email-masked]> wrote:
>> The issue was that as a part of exiting the default rules were being
>> deleted which resulted in the local trie being unmerged.  By moving the
>> freeing of the FIB tables up we can avoid the unmerge since there is no
>> local table left when we call the fib4_rules_exit function.
>>
> This literally means we no longer need to call ops->delete()
> in netns unregister path.

You are confusing table entries and rules.  The tables are cleared, the 
rules still have to be deleted.  This patch breaks the reference 
counting for fib_num_tclassid_users.

>
> diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
> index 68ea695..27b6e04 100644
> --- a/net/core/fib_rules.c
> +++ b/net/core/fib_rules.c
> @@ -153,8 +153,6 @@ static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
>
>          list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
>                  list_del_rcu(&rule->list);
> -               if (ops->delete)
> -                       ops->delete(rule);
>                  fib_rule_put(rule);
>          }
>   }
> diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
> index e5b6b05..1481b23 100644
> --- a/net/ipv4/fib_frontend.c
> +++ b/net/ipv4/fib_frontend.c
> @@ -1178,6 +1178,7 @@ static void ip_fib_net_exit(struct net *net)
>
>   #ifdef CONFIG_IP_MULTIPLE_TABLES
>          fib4_rules_exit(net);
> +       fib_flush_external(net); // <-------- Maybe not needed either.
>   #endif
>
>          for (i = 0; i < FIB_TABLE_HASHSZ; i++) {

Take a look at fib4_rule_delete.  There is more there than just unmerge 
and flush external.

- Alex