tcp_metrics.c

		.flags = GENL_ADMIN_PERM,
	},
};

static unsigned int tcpmhash_entries;
static int __init set_tcpmhash_entries(char *str)
{
	ssize_t ret;

	if (!str)
		return 0;

	ret = kstrtouint(str, 0, &tcpmhash_entries);
	if (ret)
		return 0;

	return 1;
}
__setup("tcpmhash_entries=", set_tcpmhash_entries);

static int __net_init tcp_net_metrics_init(struct net *net)
{
	size_t size;
	unsigned int slots;

	slots = tcpmhash_entries;
	if (!slots) {
		if (totalram_pages >= 128 * 1024)
			slots = 16 * 1024;
		else
			slots = 8 * 1024;
	}

	net->ipv4.tcp_metrics_hash_log = order_base_2(slots);
	size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log;

	net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
	if (!net->ipv4.tcp_metrics_hash)
		net->ipv4.tcp_metrics_hash = vzalloc(size);

	if (!net->ipv4.tcp_metrics_hash)
		return -ENOMEM;

	return 0;
}

static void __net_exit tcp_net_metrics_exit(struct net *net)
{
	unsigned int i;

	for (i = 0; i < (1U << net->ipv4.tcp_metrics_hash_log) ; i++) {
		struct tcp_metrics_block *tm, *next;

		tm = rcu_dereference_protected(net->ipv4.tcp_metrics_hash[i].chain, 1);
		while (tm) {
			next = rcu_dereference_protected(tm->tcpm_next, 1);
			kfree(tm);
			tm = next;
		}
	}
	if (is_vmalloc_addr(net->ipv4.tcp_metrics_hash))
		vfree(net->ipv4.tcp_metrics_hash);
	else
		kfree(net->ipv4.tcp_metrics_hash);
}

static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
	.init	=	tcp_net_metrics_init,
	.exit	=	tcp_net_metrics_exit,
};

void __init tcp_metrics_init(void)
{
	int ret;

	ret = register_pernet_subsys(&tcp_net_metrics_ops);
	if (ret < 0)
		goto cleanup;
	ret = genl_register_family_with_ops(&tcp_metrics_nl_family,
					    tcp_metrics_nl_ops,
					    ARRAY_SIZE(tcp_metrics_nl_ops));
	if (ret < 0)
		goto cleanup_subsys;
	return;

cleanup_subsys:
	unregister_pernet_subsys(&tcp_net_metrics_ops);

cleanup:
	return;
}