[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 {
	union {
		struct hlist_node	hlist;
		struct list_head	gc_list;
	} u;
	u16				family;
	u8				dir;
	u32				genid;
	struct flowi			key;
	struct flow_cache_object	*object;
};

struct flow_cache_percpu {
	struct hlist_head		*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;
	struct flow_cache_percpu __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);
EXPORT_SYMBOL(flow_cache_genid);
static struct flow_cache flow_cache_global;
static struct kmem_cache *flow_cachep __read_mostly;

static DEFINE_SPINLOCK(flow_cache_gc_lock);
static LIST_HEAD(flow_cache_gc_list);

#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_entry *fle)
{
	if (fle->object)
		fle->object->ops->delete(fle->object);
	kmem_cache_free(flow_cachep, fle);
}

static void flow_cache_gc_task(struct work_struct *work)
{
	struct list_head gc_list;
	struct flow_cache_entry *fce, *n;

	INIT_LIST_HEAD(&gc_list);
	spin_lock_bh(&flow_cache_gc_lock);
	list_splice_tail_init(&flow_cache_gc_list, &gc_list);
	spin_unlock_bh(&flow_cache_gc_lock);

	list_for_each_entry_safe(fce, n, &gc_list, u.gc_list)
		flow_entry_kill(fce);
}
static DECLARE_WORK(flow_cache_gc_work, flow_cache_gc_task);

static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
				     int deleted, struct list_head *gc_list)
{
	if (deleted) {
		fcp->hash_count -= deleted;
		spin_lock_bh(&flow_cache_gc_lock);
		list_splice_tail(gc_list, &flow_cache_gc_list);
		spin_unlock_bh(&flow_cache_gc_lock);
		schedule_work(&flow_cache_gc_work);
	}
}

static void __flow_cache_shrink(struct flow_cache *fc,
				struct flow_cache_percpu *fcp,
				int shrink_to)
{
	struct flow_cache_entry *fle;
	struct hlist_node *entry, *tmp;
	LIST_HEAD(gc_list);
	int i, deleted = 0;

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

		hlist_for_each_entry_safe(fle, entry, tmp,
					  &fcp->hash_table[i], u.hlist) {
			if (saved < shrink_to &&
			    flow_entry_valid(fle)) {
				saved++;
			} else {
				deleted++;
				hlist_del(&fle->u.hlist);
				list_add_tail(&fle->u.gc_list, &gc_list);
			}
		}
	}

	flow_cache_queue_garbage(fcp, deleted, &gc_list);
}

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);
}

typedef unsigned long flow_compare_t;

/* 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, *tfle;
	struct hlist_node *entry;
	struct flow_cache_object *flo;
	unsigned int hash;

	local_bh_disable();
	fcp = this_cpu_ptr(fc->percpu);

	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);
	hlist_for_each_entry(tfle, entry, &fcp->hash_table[hash], u.hlist) {
		if (tfle->family == family &&
		    tfle->dir == dir &&
		    flow_key_compare(key, &tfle->key) == 0) {
			fle = tfle;
			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->family = family;
			fle->dir = dir;
			memcpy(&fle->key, key, sizeof(*key));
			fle->object = NULL;
			hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
			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;
}
EXPORT_SYMBOL(flow_cache_lookup);

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;
	struct flow_cache_entry *fle;
	struct hlist_node *entry, *tmp;
	LIST_HEAD(gc_list);
	int i, deleted = 0;

	fcp = this_cpu_ptr(fc->percpu);
	for (i = 0; i < flow_cache_hash_size(fc); i++) {
		hlist_for_each_entry_safe(fle, entry, tmp,
					  &fcp->hash_table[i], u.hlist) {
			if (flow_entry_valid(fle))
				continue;

			deleted++;
			hlist_del(&fle->u.hlist);
			list_add_tail(&fle->u.gc_list, &gc_list);
		}
	}

	flow_cache_queue_garbage(fcp, deleted, &gc_list);

	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 int __cpuinit flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
{
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
	size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);

	if (!fcp->hash_table) {
		fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
		if (!fcp->hash_table) {
			pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
			return -ENOMEM;
		}
		fcp->hash_rnd_recalc = 1;
		fcp->hash_count = 0;
		tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
	}
	return 0;
}

static int __cpuinit 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 res, cpu = (unsigned long) hcpu;
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
		res = flow_cache_cpu_prepare(fc, cpu);
		if (res)
			return notifier_from_errno(res);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		__flow_cache_shrink(fc, fcp, 0);
		break;
	}
	return NOTIFY_OK;
}

static int __init flow_cache_init(struct flow_cache *fc)
{
	int i;

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

	fc->percpu = alloc_percpu(struct flow_cache_percpu);
	if (!fc->percpu)
		return -ENOMEM;

	for_each_online_cpu(i) {
		if (flow_cache_cpu_prepare(fc, i))
			return -ENOMEM;
	}
	fc->hotcpu_notifier = (struct notifier_block){
		.notifier_call = flow_cache_cpu,
	};
	register_hotcpu_notifier(&fc->hotcpu_notifier);

	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);

	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);
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 {
8e479560 TT	29	union {
	30	struct hlist_node hlist;
	31	struct list_head gc_list;
	32	} u;
fe1a5f03 TT	33	u16 family;
	34	u8 dir;
	35	u32 genid;
	36	struct flowi key;
	37	struct flow_cache_object *object;
1da177e4 LT	38	};
1da177e4 LT	39
d7997fe1	40	struct flow_cache_percpu {
8e479560	41	struct hlist_head *hash_table;
d7997fe1 TT	42	int hash_count;
	43	u32 hash_rnd;
	44	int hash_rnd_recalc;
	45	struct tasklet_struct flush_tasklet;
5f58a5c8	46	};
1da177e4 LT	47
1da177e4 LT	48	struct flow_flush_info {
fe1a5f03	49	struct flow_cache *cache;
d7997fe1 TT	50	atomic_t cpuleft;
d7997fe1 TT	51	struct completion completion;
1da177e4	52	};
1da177e4	53
d7997fe1 TT	54	struct flow_cache {
d7997fe1 TT	55	u32 hash_shift;
83b6b1f5	56	struct flow_cache_percpu __percpu *percpu;
d7997fe1 TT	57	struct notifier_block hotcpu_notifier;
	58	int low_watermark;
	59	int high_watermark;
	60	struct timer_list rnd_timer;
	61	};
	62
	63	atomic_t flow_cache_genid = ATOMIC_INIT(0);
9e34a5b5	64	EXPORT_SYMBOL(flow_cache_genid);
d7997fe1	65	static struct flow_cache flow_cache_global;
83b6b1f5	66	static struct kmem_cache *flow_cachep __read_mostly;
d7997fe1	67
8e479560 TT	68	static DEFINE_SPINLOCK(flow_cache_gc_lock);
	69	static LIST_HEAD(flow_cache_gc_list);
	70
d7997fe1 TT	71	#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
d7997fe1 TT	72	#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
1da177e4 LT	73
	74	static void flow_cache_new_hashrnd(unsigned long arg)
	75	{
d7997fe1	76	struct flow_cache fc = (void ) arg;
1da177e4 LT	77	int i;
1da177e4 LT	78
6f912042	79	for_each_possible_cpu(i)
d7997fe1	80	per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
1da177e4	81
d7997fe1 TT	82	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
d7997fe1 TT	83	add_timer(&fc->rnd_timer);
1da177e4 LT	84	}
1da177e4 LT	85
fe1a5f03 TT	86	static int flow_entry_valid(struct flow_cache_entry *fle)
	87	{
	88	if (atomic_read(&flow_cache_genid) != fle->genid)
	89	return 0;
	90	if (fle->object && !fle->object->ops->check(fle->object))
	91	return 0;
	92	return 1;
	93	}
	94
8e479560	95	static void flow_entry_kill(struct flow_cache_entry *fle)
134b0fc5 JM	96	{
134b0fc5 JM	97	if (fle->object)
fe1a5f03	98	fle->object->ops->delete(fle->object);
134b0fc5	99	kmem_cache_free(flow_cachep, fle);
8e479560 TT	100	}
	101
	102	static void flow_cache_gc_task(struct work_struct *work)
	103	{
	104	struct list_head gc_list;
	105	struct flow_cache_entry fce, n;
	106
	107	INIT_LIST_HEAD(&gc_list);
	108	spin_lock_bh(&flow_cache_gc_lock);
	109	list_splice_tail_init(&flow_cache_gc_list, &gc_list);
	110	spin_unlock_bh(&flow_cache_gc_lock);
	111
	112	list_for_each_entry_safe(fce, n, &gc_list, u.gc_list)
	113	flow_entry_kill(fce);
	114	}
	115	static DECLARE_WORK(flow_cache_gc_work, flow_cache_gc_task);
	116
	117	static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
	118	int deleted, struct list_head *gc_list)
	119	{
	120	if (deleted) {
	121	fcp->hash_count -= deleted;
	122	spin_lock_bh(&flow_cache_gc_lock);
	123	list_splice_tail(gc_list, &flow_cache_gc_list);
	124	spin_unlock_bh(&flow_cache_gc_lock);
	125	schedule_work(&flow_cache_gc_work);
	126	}
134b0fc5 JM	127	}
134b0fc5 JM	128
d7997fe1 TT	129	static void __flow_cache_shrink(struct flow_cache *fc,
	130	struct flow_cache_percpu *fcp,
	131	int shrink_to)
1da177e4	132	{
8e479560 TT	133	struct flow_cache_entry *fle;
	134	struct hlist_node entry, tmp;
	135	LIST_HEAD(gc_list);
	136	int i, deleted = 0;
1da177e4	137
d7997fe1	138	for (i = 0; i < flow_cache_hash_size(fc); i++) {
fe1a5f03	139	int saved = 0;
1da177e4	140
8e479560 TT	141	hlist_for_each_entry_safe(fle, entry, tmp,
8e479560 TT	142	&fcp->hash_table[i], u.hlist) {
fe1a5f03 TT	143	if (saved < shrink_to &&
	144	flow_entry_valid(fle)) {
	145	saved++;
fe1a5f03	146	} else {
8e479560 TT	147	deleted++;
	148	hlist_del(&fle->u.hlist);
	149	list_add_tail(&fle->u.gc_list, &gc_list);
fe1a5f03	150	}
1da177e4 LT	151	}
1da177e4 LT	152	}
8e479560 TT	153
8e479560 TT	154	flow_cache_queue_garbage(fcp, deleted, &gc_list);
1da177e4 LT	155	}
1da177e4 LT	156
d7997fe1 TT	157	static void flow_cache_shrink(struct flow_cache *fc,
d7997fe1 TT	158	struct flow_cache_percpu *fcp)
1da177e4	159	{
d7997fe1	160	int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
1da177e4	161
d7997fe1	162	__flow_cache_shrink(fc, fcp, shrink_to);
1da177e4 LT	163	}
1da177e4 LT	164
d7997fe1 TT	165	static void flow_new_hash_rnd(struct flow_cache *fc,
d7997fe1 TT	166	struct flow_cache_percpu *fcp)
1da177e4	167	{
d7997fe1 TT	168	get_random_bytes(&fcp->hash_rnd, sizeof(u32));
	169	fcp->hash_rnd_recalc = 0;
	170	__flow_cache_shrink(fc, fcp, 0);
1da177e4 LT	171	}
1da177e4 LT	172
d7997fe1 TT	173	static u32 flow_hash_code(struct flow_cache *fc,
	174	struct flow_cache_percpu *fcp,
	175	struct flowi *key)
1da177e4 LT	176	{
	177	u32 k = (u32 ) key;
	178
a02cec21 ED	179	return jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
a02cec21 ED	180	& (flow_cache_hash_size(fc) - 1);
1da177e4 LT	181	}
1da177e4 LT	182
83b6b1f5	183	typedef unsigned long flow_compare_t;
1da177e4	184
1da177e4 LT	185	/* I hear what you're saying, use memcmp. But memcmp cannot make
	186	* important assumptions that we can here, such as alignment and
	187	* constant size.
	188	*/
	189	static int flow_key_compare(struct flowi key1, struct flowi key2)
	190	{
	191	flow_compare_t k1, k1_lim, *k2;
	192	const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);
	193
f0fe91de	194	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));
1da177e4 LT	195
	196	k1 = (flow_compare_t *) key1;
	197	k1_lim = k1 + n_elem;
	198
	199	k2 = (flow_compare_t *) key2;
	200
	201	do {
	202	if (k1++ != k2++)
	203	return 1;
	204	} while (k1 < k1_lim);
	205
	206	return 0;
	207	}
	208
fe1a5f03 TT	209	struct flow_cache_object *
	210	flow_cache_lookup(struct net net, struct flowi key, u16 family, u8 dir,
	211	flow_resolve_t resolver, void *ctx)
1da177e4	212	{
d7997fe1 TT	213	struct flow_cache *fc = &flow_cache_global;
d7997fe1 TT	214	struct flow_cache_percpu *fcp;
8e479560 TT	215	struct flow_cache_entry fle, tfle;
8e479560 TT	216	struct hlist_node *entry;
fe1a5f03	217	struct flow_cache_object *flo;
1da177e4	218	unsigned int hash;
1da177e4 LT	219
1da177e4 LT	220	local_bh_disable();
7a9b2d59	221	fcp = this_cpu_ptr(fc->percpu);
1da177e4 LT	222
1da177e4 LT	223	fle = NULL;
fe1a5f03	224	flo = NULL;
1da177e4 LT	225	/* Packet really early in init? Making flow_cache_init a
1da177e4 LT	226	* pre-smp initcall would solve this. --RR */
d7997fe1	227	if (!fcp->hash_table)
1da177e4 LT	228	goto nocache;
1da177e4 LT	229
d7997fe1 TT	230	if (fcp->hash_rnd_recalc)
d7997fe1 TT	231	flow_new_hash_rnd(fc, fcp);
1da177e4	232
fe1a5f03	233	hash = flow_hash_code(fc, fcp, key);
8e479560 TT	234	hlist_for_each_entry(tfle, entry, &fcp->hash_table[hash], u.hlist) {
	235	if (tfle->family == family &&
	236	tfle->dir == dir &&
	237	flow_key_compare(key, &tfle->key) == 0) {
	238	fle = tfle;
1da177e4	239	break;
8e479560	240	}
1da177e4 LT	241	}
1da177e4 LT	242
fe1a5f03	243	if (unlikely(!fle)) {
d7997fe1 TT	244	if (fcp->hash_count > fc->high_watermark)
d7997fe1 TT	245	flow_cache_shrink(fc, fcp);
1da177e4	246
54e6ecb2	247	fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
1da177e4	248	if (fle) {
1da177e4 LT	249	fle->family = family;
	250	fle->dir = dir;
	251	memcpy(&fle->key, key, sizeof(*key));
	252	fle->object = NULL;
8e479560	253	hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
d7997fe1	254	fcp->hash_count++;
1da177e4	255	}
fe1a5f03 TT	256	} else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
	257	flo = fle->object;
	258	if (!flo)
	259	goto ret_object;
	260	flo = flo->ops->get(flo);
	261	if (flo)
	262	goto ret_object;
	263	} else if (fle->object) {
	264	flo = fle->object;
	265	flo->ops->delete(flo);
	266	fle->object = NULL;
1da177e4 LT	267	}
	268
	269	nocache:
fe1a5f03 TT	270	flo = NULL;
	271	if (fle) {
	272	flo = fle->object;
	273	fle->object = NULL;
	274	}
	275	flo = resolver(net, key, family, dir, flo, ctx);
	276	if (fle) {
	277	fle->genid = atomic_read(&flow_cache_genid);
	278	if (!IS_ERR(flo))
	279	fle->object = flo;
	280	else
	281	fle->genid--;
	282	} else {
	283	if (flo && !IS_ERR(flo))
	284	flo->ops->delete(flo);
1da177e4	285	}
fe1a5f03 TT	286	ret_object:
	287	local_bh_enable();
	288	return flo;
1da177e4	289	}
9e34a5b5	290	EXPORT_SYMBOL(flow_cache_lookup);
1da177e4 LT	291
	292	static void flow_cache_flush_tasklet(unsigned long data)
	293	{
	294	struct flow_flush_info info = (void )data;
d7997fe1 TT	295	struct flow_cache *fc = info->cache;
d7997fe1 TT	296	struct flow_cache_percpu *fcp;
8e479560 TT	297	struct flow_cache_entry *fle;
	298	struct hlist_node entry, tmp;
	299	LIST_HEAD(gc_list);
	300	int i, deleted = 0;
1da177e4	301
7a9b2d59	302	fcp = this_cpu_ptr(fc->percpu);
d7997fe1	303	for (i = 0; i < flow_cache_hash_size(fc); i++) {
8e479560 TT	304	hlist_for_each_entry_safe(fle, entry, tmp,
8e479560 TT	305	&fcp->hash_table[i], u.hlist) {
fe1a5f03	306	if (flow_entry_valid(fle))
1da177e4 LT	307	continue;
1da177e4 LT	308
8e479560 TT	309	deleted++;
	310	hlist_del(&fle->u.hlist);
	311	list_add_tail(&fle->u.gc_list, &gc_list);
1da177e4 LT	312	}
	313	}
	314
8e479560 TT	315	flow_cache_queue_garbage(fcp, deleted, &gc_list);
8e479560 TT	316
1da177e4 LT	317	if (atomic_dec_and_test(&info->cpuleft))
	318	complete(&info->completion);
	319	}
	320
1da177e4 LT	321	static void flow_cache_flush_per_cpu(void *data)
	322	{
	323	struct flow_flush_info *info = data;
	324	int cpu;
	325	struct tasklet_struct *tasklet;
	326
	327	cpu = smp_processor_id();
d7997fe1	328	tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
1da177e4 LT	329	tasklet->data = (unsigned long)info;
	330	tasklet_schedule(tasklet);
	331	}
	332
	333	void flow_cache_flush(void)
	334	{
	335	struct flow_flush_info info;
4a3e2f71	336	static DEFINE_MUTEX(flow_flush_sem);
1da177e4 LT	337
1da177e4 LT	338	/* Don't want cpus going down or up during this. */
86ef5c9a	339	get_online_cpus();
4a3e2f71	340	mutex_lock(&flow_flush_sem);
d7997fe1	341	info.cache = &flow_cache_global;
1da177e4 LT	342	atomic_set(&info.cpuleft, num_online_cpus());
	343	init_completion(&info.completion);
	344
	345	local_bh_disable();
8691e5a8	346	smp_call_function(flow_cache_flush_per_cpu, &info, 0);
1da177e4 LT	347	flow_cache_flush_tasklet((unsigned long)&info);
	348	local_bh_enable();
	349
	350	wait_for_completion(&info.completion);
4a3e2f71	351	mutex_unlock(&flow_flush_sem);
86ef5c9a	352	put_online_cpus();
1da177e4 LT	353	}
1da177e4 LT	354
83b6b1f5	355	static int __cpuinit flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
1da177e4	356	{
83b6b1f5 ED	357	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
83b6b1f5 ED	358	size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);
d7997fe1	359
83b6b1f5 ED	360	if (!fcp->hash_table) {
	361	fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
	362	if (!fcp->hash_table) {
	363	pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
	364	return -ENOMEM;
	365	}
	366	fcp->hash_rnd_recalc = 1;
	367	fcp->hash_count = 0;
	368	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
	369	}
	370	return 0;
1da177e4 LT	371	}
1da177e4 LT	372
83b6b1f5	373	static int __cpuinit flow_cache_cpu(struct notifier_block *nfb,
1da177e4 LT	374	unsigned long action,
	375	void *hcpu)
	376	{
d7997fe1	377	struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
83b6b1f5	378	int res, cpu = (unsigned long) hcpu;
d7997fe1 TT	379	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
d7997fe1 TT	380
83b6b1f5 ED	381	switch (action) {
	382	case CPU_UP_PREPARE:
	383	case CPU_UP_PREPARE_FROZEN:
	384	res = flow_cache_cpu_prepare(fc, cpu);
	385	if (res)
	386	return notifier_from_errno(res);
	387	break;
	388	case CPU_DEAD:
	389	case CPU_DEAD_FROZEN:
d7997fe1	390	__flow_cache_shrink(fc, fcp, 0);
83b6b1f5 ED	391	break;
83b6b1f5 ED	392	}
1da177e4 LT	393	return NOTIFY_OK;
1da177e4 LT	394	}
1da177e4	395
83b6b1f5	396	static int __init flow_cache_init(struct flow_cache *fc)
1da177e4 LT	397	{
	398	int i;
	399
d7997fe1 TT	400	fc->hash_shift = 10;
	401	fc->low_watermark = 2 * flow_cache_hash_size(fc);
	402	fc->high_watermark = 4 * flow_cache_hash_size(fc);
	403
d7997fe1	404	fc->percpu = alloc_percpu(struct flow_cache_percpu);
83b6b1f5 ED	405	if (!fc->percpu)
83b6b1f5 ED	406	return -ENOMEM;
1da177e4	407
83b6b1f5 ED	408	for_each_online_cpu(i) {
	409	if (flow_cache_cpu_prepare(fc, i))
	410	return -ENOMEM;
	411	}
d7997fe1 TT	412	fc->hotcpu_notifier = (struct notifier_block){
	413	.notifier_call = flow_cache_cpu,
	414	};
	415	register_hotcpu_notifier(&fc->hotcpu_notifier);
1da177e4	416
83b6b1f5 ED	417	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
	418	(unsigned long) fc);
	419	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	420	add_timer(&fc->rnd_timer);
	421
1da177e4 LT	422	return 0;
	423	}
	424
d7997fe1 TT	425	static int __init flow_cache_init_global(void)
	426	{
	427	flow_cachep = kmem_cache_create("flow_cache",
	428	sizeof(struct flow_cache_entry),
	429	0, SLAB_PANIC, NULL);
	430
	431	return flow_cache_init(&flow_cache_global);
	432	}
	433
	434	module_init(flow_cache_init_global);