[net-next-2.6.git] / net / core / flow.c

/* flow.c: Generic flow cache.
 *
 * Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/mutex.h>
#include <net/flow.h>
#include <asm/atomic.h>
#include <linux/security.h>

struct flow_cache_entry {
	struct flow_cache_entry		*next;
	u16				family;
	u8				dir;
	u32				genid;
	struct flowi			key;
	struct flow_cache_object	*object;
};

struct flow_cache_percpu {
	struct flow_cache_entry		**hash_table;
	int				hash_count;
	u32				hash_rnd;
	int				hash_rnd_recalc;
	struct tasklet_struct		flush_tasklet;
};

struct flow_flush_info {
	struct flow_cache		*cache;
	atomic_t			cpuleft;
	struct completion		completion;
};

struct flow_cache {
	u32				hash_shift;
	unsigned long			order;
	struct flow_cache_percpu	*percpu;
	struct notifier_block		hotcpu_notifier;
	int				low_watermark;
	int				high_watermark;
	struct timer_list		rnd_timer;
};

atomic_t flow_cache_genid = ATOMIC_INIT(0);
static struct flow_cache flow_cache_global;
static struct kmem_cache *flow_cachep;

#define flow_cache_hash_size(cache)	(1 << (cache)->hash_shift)
#define FLOW_HASH_RND_PERIOD		(10 * 60 * HZ)

static void flow_cache_new_hashrnd(unsigned long arg)
{
	struct flow_cache *fc = (void *) arg;
	int i;

	for_each_possible_cpu(i)
		per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;

	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	add_timer(&fc->rnd_timer);
}

static int flow_entry_valid(struct flow_cache_entry *fle)
{
	if (atomic_read(&flow_cache_genid) != fle->genid)
		return 0;
	if (fle->object && !fle->object->ops->check(fle->object))
		return 0;
	return 1;
}

static void flow_entry_kill(struct flow_cache *fc,
			    struct flow_cache_percpu *fcp,
			    struct flow_cache_entry *fle)
{
	if (fle->object)
		fle->object->ops->delete(fle->object);
	kmem_cache_free(flow_cachep, fle);
	fcp->hash_count--;
}

static void __flow_cache_shrink(struct flow_cache *fc,
				struct flow_cache_percpu *fcp,
				int shrink_to)
{
	struct flow_cache_entry *fle, **flp;
	int i;

	for (i = 0; i < flow_cache_hash_size(fc); i++) {
		int saved = 0;

		flp = &fcp->hash_table[i];
		while ((fle = *flp) != NULL) {
			if (saved < shrink_to &&
			    flow_entry_valid(fle)) {
				saved++;
				flp = &fle->next;
			} else {
				*flp = fle->next;
				flow_entry_kill(fc, fcp, fle);
			}
		}
	}
}

static void flow_cache_shrink(struct flow_cache *fc,
			      struct flow_cache_percpu *fcp)
{
	int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);

	__flow_cache_shrink(fc, fcp, shrink_to);
}

static void flow_new_hash_rnd(struct flow_cache *fc,
			      struct flow_cache_percpu *fcp)
{
	get_random_bytes(&fcp->hash_rnd, sizeof(u32));
	fcp->hash_rnd_recalc = 0;
	__flow_cache_shrink(fc, fcp, 0);
}

static u32 flow_hash_code(struct flow_cache *fc,
			  struct flow_cache_percpu *fcp,
			  struct flowi *key)
{
	u32 *k = (u32 *) key;

	return (jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
		& (flow_cache_hash_size(fc) - 1));
}

#if (BITS_PER_LONG == 64)
typedef u64 flow_compare_t;
#else
typedef u32 flow_compare_t;
#endif

/* I hear what you're saying, use memcmp.  But memcmp cannot make
 * important assumptions that we can here, such as alignment and
 * constant size.
 */
static int flow_key_compare(struct flowi *key1, struct flowi *key2)
{
	flow_compare_t *k1, *k1_lim, *k2;
	const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);

	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));

	k1 = (flow_compare_t *) key1;
	k1_lim = k1 + n_elem;

	k2 = (flow_compare_t *) key2;

	do {
		if (*k1++ != *k2++)
			return 1;
	} while (k1 < k1_lim);

	return 0;
}

struct flow_cache_object *
flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
		  flow_resolve_t resolver, void *ctx)
{
	struct flow_cache *fc = &flow_cache_global;
	struct flow_cache_percpu *fcp;
	struct flow_cache_entry *fle, **head;
	struct flow_cache_object *flo;
	unsigned int hash;

	local_bh_disable();
	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());

	fle = NULL;
	flo = NULL;
	/* Packet really early in init?  Making flow_cache_init a
	 * pre-smp initcall would solve this.  --RR */
	if (!fcp->hash_table)
		goto nocache;

	if (fcp->hash_rnd_recalc)
		flow_new_hash_rnd(fc, fcp);

	hash = flow_hash_code(fc, fcp, key);
	head = &fcp->hash_table[hash];
	for (fle = *head; fle; fle = fle->next) {
		if (fle->family == family &&
		    fle->dir == dir &&
		    flow_key_compare(key, &fle->key) == 0)
			break;
	}

	if (unlikely(!fle)) {
		if (fcp->hash_count > fc->high_watermark)
			flow_cache_shrink(fc, fcp);

		fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
		if (fle) {
			fle->next = *head;
			*head = fle;
			fle->family = family;
			fle->dir = dir;
			memcpy(&fle->key, key, sizeof(*key));
			fle->object = NULL;
			fcp->hash_count++;
		}
	} else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
		flo = fle->object;
		if (!flo)
			goto ret_object;
		flo = flo->ops->get(flo);
		if (flo)
			goto ret_object;
	} else if (fle->object) {
	        flo = fle->object;
	        flo->ops->delete(flo);
	        fle->object = NULL;
	}

nocache:
	flo = NULL;
	if (fle) {
		flo = fle->object;
		fle->object = NULL;
	}
	flo = resolver(net, key, family, dir, flo, ctx);
	if (fle) {
		fle->genid = atomic_read(&flow_cache_genid);
		if (!IS_ERR(flo))
			fle->object = flo;
		else
			fle->genid--;
	} else {
		if (flo && !IS_ERR(flo))
			flo->ops->delete(flo);
	}
ret_object:
	local_bh_enable();
	return flo;
}

static void flow_cache_flush_tasklet(unsigned long data)
{
	struct flow_flush_info *info = (void *)data;
	struct flow_cache *fc = info->cache;
	struct flow_cache_percpu *fcp;
	int i;

	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
	for (i = 0; i < flow_cache_hash_size(fc); i++) {
		struct flow_cache_entry *fle;

		fle = fcp->hash_table[i];
		for (; fle; fle = fle->next) {
			if (flow_entry_valid(fle))
				continue;

			if (fle->object)
				fle->object->ops->delete(fle->object);
			fle->object = NULL;
		}
	}

	if (atomic_dec_and_test(&info->cpuleft))
		complete(&info->completion);
}

static void flow_cache_flush_per_cpu(void *data)
{
	struct flow_flush_info *info = data;
	int cpu;
	struct tasklet_struct *tasklet;

	cpu = smp_processor_id();
	tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
	tasklet->data = (unsigned long)info;
	tasklet_schedule(tasklet);
}

void flow_cache_flush(void)
{
	struct flow_flush_info info;
	static DEFINE_MUTEX(flow_flush_sem);

	/* Don't want cpus going down or up during this. */
	get_online_cpus();
	mutex_lock(&flow_flush_sem);
	info.cache = &flow_cache_global;
	atomic_set(&info.cpuleft, num_online_cpus());
	init_completion(&info.completion);

	local_bh_disable();
	smp_call_function(flow_cache_flush_per_cpu, &info, 0);
	flow_cache_flush_tasklet((unsigned long)&info);
	local_bh_enable();

	wait_for_completion(&info.completion);
	mutex_unlock(&flow_flush_sem);
	put_online_cpus();
}

static void __init flow_cache_cpu_prepare(struct flow_cache *fc,
					  struct flow_cache_percpu *fcp)
{
	fcp->hash_table = (struct flow_cache_entry **)
		__get_free_pages(GFP_KERNEL|__GFP_ZERO, fc->order);
	if (!fcp->hash_table)
		panic("NET: failed to allocate flow cache order %lu\n", fc->order);

	fcp->hash_rnd_recalc = 1;
	fcp->hash_count = 0;
	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
}

static int flow_cache_cpu(struct notifier_block *nfb,
			  unsigned long action,
			  void *hcpu)
{
	struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
	int cpu = (unsigned long) hcpu;
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
		__flow_cache_shrink(fc, fcp, 0);
	return NOTIFY_OK;
}

static int flow_cache_init(struct flow_cache *fc)
{
	unsigned long order;
	int i;

	fc->hash_shift = 10;
	fc->low_watermark = 2 * flow_cache_hash_size(fc);
	fc->high_watermark = 4 * flow_cache_hash_size(fc);

	for (order = 0;
	     (PAGE_SIZE << order) <
		     (sizeof(struct flow_cache_entry *)*flow_cache_hash_size(fc));
	     order++)
		/* NOTHING */;
	fc->order = order;
	fc->percpu = alloc_percpu(struct flow_cache_percpu);

	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
		    (unsigned long) fc);
	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	add_timer(&fc->rnd_timer);

	for_each_possible_cpu(i)
		flow_cache_cpu_prepare(fc, per_cpu_ptr(fc->percpu, i));

	fc->hotcpu_notifier = (struct notifier_block){
		.notifier_call = flow_cache_cpu,
	};
	register_hotcpu_notifier(&fc->hotcpu_notifier);

	return 0;
}

static int __init flow_cache_init_global(void)
{
	flow_cachep = kmem_cache_create("flow_cache",
					sizeof(struct flow_cache_entry),
					0, SLAB_PANIC, NULL);

	return flow_cache_init(&flow_cache_global);
}

module_init(flow_cache_init_global);

EXPORT_SYMBOL(flow_cache_genid);
EXPORT_SYMBOL(flow_cache_lookup);
Commit	Line	Data
1da177e4 LT	1	/* flow.c: Generic flow cache.
	2	*
	3	* Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
	4	* Copyright (C) 2003 David S. Miller (davem@redhat.com)
	5	*/
	6
	7	#include <linux/kernel.h>
	8	#include <linux/module.h>
	9	#include <linux/list.h>
	10	#include <linux/jhash.h>
	11	#include <linux/interrupt.h>
	12	#include <linux/mm.h>
	13	#include <linux/random.h>
	14	#include <linux/init.h>
	15	#include <linux/slab.h>
	16	#include <linux/smp.h>
	17	#include <linux/completion.h>
	18	#include <linux/percpu.h>
	19	#include <linux/bitops.h>
	20	#include <linux/notifier.h>
	21	#include <linux/cpu.h>
	22	#include <linux/cpumask.h>
4a3e2f71	23	#include <linux/mutex.h>
1da177e4 LT	24	#include <net/flow.h>
1da177e4 LT	25	#include <asm/atomic.h>
df71837d	26	#include <linux/security.h>
1da177e4 LT	27
1da177e4 LT	28	struct flow_cache_entry {
fe1a5f03 TT	29	struct flow_cache_entry *next;
	30	u16 family;
	31	u8 dir;
	32	u32 genid;
	33	struct flowi key;
	34	struct flow_cache_object *object;
1da177e4 LT	35	};
1da177e4 LT	36
d7997fe1	37	struct flow_cache_percpu {
fe1a5f03	38	struct flow_cache_entry **hash_table;
d7997fe1 TT	39	int hash_count;
	40	u32 hash_rnd;
	41	int hash_rnd_recalc;
	42	struct tasklet_struct flush_tasklet;
5f58a5c8	43	};
1da177e4 LT	44
1da177e4 LT	45	struct flow_flush_info {
fe1a5f03	46	struct flow_cache *cache;
d7997fe1 TT	47	atomic_t cpuleft;
d7997fe1 TT	48	struct completion completion;
1da177e4	49	};
1da177e4	50
d7997fe1 TT	51	struct flow_cache {
	52	u32 hash_shift;
	53	unsigned long order;
fe1a5f03	54	struct flow_cache_percpu *percpu;
d7997fe1 TT	55	struct notifier_block hotcpu_notifier;
	56	int low_watermark;
	57	int high_watermark;
	58	struct timer_list rnd_timer;
	59	};
	60
	61	atomic_t flow_cache_genid = ATOMIC_INIT(0);
	62	static struct flow_cache flow_cache_global;
	63	static struct kmem_cache *flow_cachep;
	64
	65	#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
	66	#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
1da177e4 LT	67
	68	static void flow_cache_new_hashrnd(unsigned long arg)
	69	{
d7997fe1	70	struct flow_cache fc = (void ) arg;
1da177e4 LT	71	int i;
1da177e4 LT	72
6f912042	73	for_each_possible_cpu(i)
d7997fe1	74	per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
1da177e4	75
d7997fe1 TT	76	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
d7997fe1 TT	77	add_timer(&fc->rnd_timer);
1da177e4 LT	78	}
1da177e4 LT	79
fe1a5f03 TT	80	static int flow_entry_valid(struct flow_cache_entry *fle)
	81	{
	82	if (atomic_read(&flow_cache_genid) != fle->genid)
	83	return 0;
	84	if (fle->object && !fle->object->ops->check(fle->object))
	85	return 0;
	86	return 1;
	87	}
	88
d7997fe1 TT	89	static void flow_entry_kill(struct flow_cache *fc,
	90	struct flow_cache_percpu *fcp,
	91	struct flow_cache_entry *fle)
134b0fc5 JM	92	{
134b0fc5 JM	93	if (fle->object)
fe1a5f03	94	fle->object->ops->delete(fle->object);
134b0fc5	95	kmem_cache_free(flow_cachep, fle);
d7997fe1	96	fcp->hash_count--;
134b0fc5 JM	97	}
134b0fc5 JM	98
d7997fe1 TT	99	static void __flow_cache_shrink(struct flow_cache *fc,
	100	struct flow_cache_percpu *fcp,
	101	int shrink_to)
1da177e4 LT	102	{
	103	struct flow_cache_entry fle, *flp;
	104	int i;
	105
d7997fe1	106	for (i = 0; i < flow_cache_hash_size(fc); i++) {
fe1a5f03	107	int saved = 0;
1da177e4	108
d7997fe1	109	flp = &fcp->hash_table[i];
1da177e4	110	while ((fle = *flp) != NULL) {
fe1a5f03 TT	111	if (saved < shrink_to &&
	112	flow_entry_valid(fle)) {
	113	saved++;
	114	flp = &fle->next;
	115	} else {
	116	*flp = fle->next;
	117	flow_entry_kill(fc, fcp, fle);
	118	}
1da177e4 LT	119	}
	120	}
	121	}
	122
d7997fe1 TT	123	static void flow_cache_shrink(struct flow_cache *fc,
d7997fe1 TT	124	struct flow_cache_percpu *fcp)
1da177e4	125	{
d7997fe1	126	int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
1da177e4	127
d7997fe1	128	__flow_cache_shrink(fc, fcp, shrink_to);
1da177e4 LT	129	}
1da177e4 LT	130
d7997fe1 TT	131	static void flow_new_hash_rnd(struct flow_cache *fc,
d7997fe1 TT	132	struct flow_cache_percpu *fcp)
1da177e4	133	{
d7997fe1 TT	134	get_random_bytes(&fcp->hash_rnd, sizeof(u32));
	135	fcp->hash_rnd_recalc = 0;
	136	__flow_cache_shrink(fc, fcp, 0);
1da177e4 LT	137	}
1da177e4 LT	138
d7997fe1 TT	139	static u32 flow_hash_code(struct flow_cache *fc,
	140	struct flow_cache_percpu *fcp,
	141	struct flowi *key)
1da177e4 LT	142	{
	143	u32 k = (u32 ) key;
	144
d7997fe1 TT	145	return (jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
d7997fe1 TT	146	& (flow_cache_hash_size(fc) - 1));
1da177e4 LT	147	}
	148
	149	#if (BITS_PER_LONG == 64)
	150	typedef u64 flow_compare_t;
	151	#else
	152	typedef u32 flow_compare_t;
	153	#endif
	154
1da177e4 LT	155	/* I hear what you're saying, use memcmp. But memcmp cannot make
	156	* important assumptions that we can here, such as alignment and
	157	* constant size.
	158	*/
	159	static int flow_key_compare(struct flowi key1, struct flowi key2)
	160	{
	161	flow_compare_t k1, k1_lim, *k2;
	162	const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);
	163
f0fe91de	164	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));
1da177e4 LT	165
	166	k1 = (flow_compare_t *) key1;
	167	k1_lim = k1 + n_elem;
	168
	169	k2 = (flow_compare_t *) key2;
	170
	171	do {
	172	if (k1++ != k2++)
	173	return 1;
	174	} while (k1 < k1_lim);
	175
	176	return 0;
	177	}
	178
fe1a5f03 TT	179	struct flow_cache_object *
	180	flow_cache_lookup(struct net net, struct flowi key, u16 family, u8 dir,
	181	flow_resolve_t resolver, void *ctx)
1da177e4	182	{
d7997fe1 TT	183	struct flow_cache *fc = &flow_cache_global;
d7997fe1 TT	184	struct flow_cache_percpu *fcp;
1da177e4	185	struct flow_cache_entry fle, *head;
fe1a5f03	186	struct flow_cache_object *flo;
1da177e4	187	unsigned int hash;
1da177e4 LT	188
1da177e4 LT	189	local_bh_disable();
d7997fe1	190	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
1da177e4 LT	191
1da177e4 LT	192	fle = NULL;
fe1a5f03	193	flo = NULL;
1da177e4 LT	194	/* Packet really early in init? Making flow_cache_init a
1da177e4 LT	195	* pre-smp initcall would solve this. --RR */
d7997fe1	196	if (!fcp->hash_table)
1da177e4 LT	197	goto nocache;
1da177e4 LT	198
d7997fe1 TT	199	if (fcp->hash_rnd_recalc)
d7997fe1 TT	200	flow_new_hash_rnd(fc, fcp);
1da177e4	201
fe1a5f03	202	hash = flow_hash_code(fc, fcp, key);
d7997fe1	203	head = &fcp->hash_table[hash];
1da177e4 LT	204	for (fle = *head; fle; fle = fle->next) {
	205	if (fle->family == family &&
	206	fle->dir == dir &&
fe1a5f03	207	flow_key_compare(key, &fle->key) == 0)
1da177e4	208	break;
1da177e4 LT	209	}
1da177e4 LT	210
fe1a5f03	211	if (unlikely(!fle)) {
d7997fe1 TT	212	if (fcp->hash_count > fc->high_watermark)
d7997fe1 TT	213	flow_cache_shrink(fc, fcp);
1da177e4	214
54e6ecb2	215	fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
1da177e4 LT	216	if (fle) {
	217	fle->next = *head;
	218	*head = fle;
	219	fle->family = family;
	220	fle->dir = dir;
	221	memcpy(&fle->key, key, sizeof(*key));
	222	fle->object = NULL;
d7997fe1	223	fcp->hash_count++;
1da177e4	224	}
fe1a5f03 TT	225	} else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
	226	flo = fle->object;
	227	if (!flo)
	228	goto ret_object;
	229	flo = flo->ops->get(flo);
	230	if (flo)
	231	goto ret_object;
	232	} else if (fle->object) {
	233	flo = fle->object;
	234	flo->ops->delete(flo);
	235	fle->object = NULL;
1da177e4 LT	236	}
	237
	238	nocache:
fe1a5f03 TT	239	flo = NULL;
	240	if (fle) {
	241	flo = fle->object;
	242	fle->object = NULL;
	243	}
	244	flo = resolver(net, key, family, dir, flo, ctx);
	245	if (fle) {
	246	fle->genid = atomic_read(&flow_cache_genid);
	247	if (!IS_ERR(flo))
	248	fle->object = flo;
	249	else
	250	fle->genid--;
	251	} else {
	252	if (flo && !IS_ERR(flo))
	253	flo->ops->delete(flo);
1da177e4	254	}
fe1a5f03 TT	255	ret_object:
	256	local_bh_enable();
	257	return flo;
1da177e4 LT	258	}
	259
	260	static void flow_cache_flush_tasklet(unsigned long data)
	261	{
	262	struct flow_flush_info info = (void )data;
d7997fe1 TT	263	struct flow_cache *fc = info->cache;
d7997fe1 TT	264	struct flow_cache_percpu *fcp;
1da177e4	265	int i;
1da177e4	266
d7997fe1 TT	267	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
d7997fe1 TT	268	for (i = 0; i < flow_cache_hash_size(fc); i++) {
1da177e4 LT	269	struct flow_cache_entry *fle;
1da177e4 LT	270
d7997fe1	271	fle = fcp->hash_table[i];
1da177e4	272	for (; fle; fle = fle->next) {
fe1a5f03	273	if (flow_entry_valid(fle))
1da177e4 LT	274	continue;
1da177e4 LT	275
fe1a5f03 TT	276	if (fle->object)
fe1a5f03 TT	277	fle->object->ops->delete(fle->object);
1da177e4	278	fle->object = NULL;
1da177e4 LT	279	}
	280	}
	281
	282	if (atomic_dec_and_test(&info->cpuleft))
	283	complete(&info->completion);
	284	}
	285
1da177e4 LT	286	static void flow_cache_flush_per_cpu(void *data)
	287	{
	288	struct flow_flush_info *info = data;
	289	int cpu;
	290	struct tasklet_struct *tasklet;
	291
	292	cpu = smp_processor_id();
d7997fe1	293	tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
1da177e4 LT	294	tasklet->data = (unsigned long)info;
	295	tasklet_schedule(tasklet);
	296	}
	297
	298	void flow_cache_flush(void)
	299	{
	300	struct flow_flush_info info;
4a3e2f71	301	static DEFINE_MUTEX(flow_flush_sem);
1da177e4 LT	302
1da177e4 LT	303	/* Don't want cpus going down or up during this. */
86ef5c9a	304	get_online_cpus();
4a3e2f71	305	mutex_lock(&flow_flush_sem);
d7997fe1	306	info.cache = &flow_cache_global;
1da177e4 LT	307	atomic_set(&info.cpuleft, num_online_cpus());
	308	init_completion(&info.completion);
	309
	310	local_bh_disable();
8691e5a8	311	smp_call_function(flow_cache_flush_per_cpu, &info, 0);
1da177e4 LT	312	flow_cache_flush_tasklet((unsigned long)&info);
	313	local_bh_enable();
	314
	315	wait_for_completion(&info.completion);
4a3e2f71	316	mutex_unlock(&flow_flush_sem);
86ef5c9a	317	put_online_cpus();
1da177e4 LT	318	}
1da177e4 LT	319
d7997fe1 TT	320	static void __init flow_cache_cpu_prepare(struct flow_cache *fc,
d7997fe1 TT	321	struct flow_cache_percpu *fcp)
1da177e4	322	{
d7997fe1 TT	323	fcp->hash_table = (struct flow_cache_entry **)
	324	__get_free_pages(GFP_KERNEL\|__GFP_ZERO, fc->order);
	325	if (!fcp->hash_table)
	326	panic("NET: failed to allocate flow cache order %lu\n", fc->order);
	327
	328	fcp->hash_rnd_recalc = 1;
	329	fcp->hash_count = 0;
	330	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
1da177e4 LT	331	}
1da177e4 LT	332
1da177e4 LT	333	static int flow_cache_cpu(struct notifier_block *nfb,
	334	unsigned long action,
	335	void *hcpu)
	336	{
d7997fe1 TT	337	struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
	338	int cpu = (unsigned long) hcpu;
	339	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
	340
8bb78442	341	if (action == CPU_DEAD \|\| action == CPU_DEAD_FROZEN)
d7997fe1	342	__flow_cache_shrink(fc, fcp, 0);
1da177e4 LT	343	return NOTIFY_OK;
1da177e4 LT	344	}
1da177e4	345
d7997fe1	346	static int flow_cache_init(struct flow_cache *fc)
1da177e4	347	{
d7997fe1	348	unsigned long order;
1da177e4 LT	349	int i;
1da177e4 LT	350
d7997fe1 TT	351	fc->hash_shift = 10;
	352	fc->low_watermark = 2 * flow_cache_hash_size(fc);
	353	fc->high_watermark = 4 * flow_cache_hash_size(fc);
	354
	355	for (order = 0;
	356	(PAGE_SIZE << order) <
	357	(sizeof(struct flow_cache_entry )flow_cache_hash_size(fc));
	358	order++)
	359	/* NOTHING */;
	360	fc->order = order;
	361	fc->percpu = alloc_percpu(struct flow_cache_percpu);
1da177e4	362
d7997fe1 TT	363	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
	364	(unsigned long) fc);
	365	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	366	add_timer(&fc->rnd_timer);
1da177e4	367
6f912042	368	for_each_possible_cpu(i)
d7997fe1 TT	369	flow_cache_cpu_prepare(fc, per_cpu_ptr(fc->percpu, i));
	370
	371	fc->hotcpu_notifier = (struct notifier_block){
	372	.notifier_call = flow_cache_cpu,
	373	};
	374	register_hotcpu_notifier(&fc->hotcpu_notifier);
1da177e4	375
1da177e4 LT	376	return 0;
	377	}
	378
d7997fe1 TT	379	static int __init flow_cache_init_global(void)
	380	{
	381	flow_cachep = kmem_cache_create("flow_cache",
	382	sizeof(struct flow_cache_entry),
	383	0, SLAB_PANIC, NULL);
	384
	385	return flow_cache_init(&flow_cache_global);
	386	}
	387
	388	module_init(flow_cache_init_global);
1da177e4 LT	389
	390	EXPORT_SYMBOL(flow_cache_genid);
	391	EXPORT_SYMBOL(flow_cache_lookup);