Re: [PATCH 3/3] nfnetlink_queue: use hash table to speed up entry finding.

[Patrick McHardy <kaber@trash.net>]

Changli Gao wrote:
> static int
> nfqnl_rcv_nl_event(struct notifier_block *this,
>                    unsigned long event, void *ptr)
> {
>         struct netlink_notify *n = ptr;
> 
>         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
>                 int i;
> 
>                 /* destroy all instances for this pid */
>                 spin_lock(&instances_lock);
>                 for (i = 0; i < INSTANCE_BUCKETS; i++) {
>                         struct hlist_node *tmp, *t2;
>                         struct nfqnl_instance *inst;
>                         struct hlist_head *head = &instance_table[i];
> 
>                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
>                                 if ((n->net == &init_net) &&
>                                     (n->pid == inst->peer_pid))
>                                         __instance_destroy(inst);
>                         }
>                 }
>                 spin_unlock(&instances_lock);
>         }
>         return NOTIFY_DONE;
> }
> 
> static struct notifier_block nfqnl_rtnl_notifier = {
>         .notifier_call  = nfqnl_rcv_nl_event,
> };
>

Ah, right. So call nfnl_lock() or convert the spinlock to a
mutex.