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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>
23#include <linux/mutex.h>
24#include <net/flow.h>
25#include <linux/atomic.h>
26#include <linux/security.h>
27
28struct flow_cache_entry {
29 union {
30 struct hlist_node hlist;
31 struct list_head gc_list;
32 } u;
33 struct net *net;
34 u16 family;
35 u8 dir;
36 u32 genid;
37 struct flowi key;
38 struct flow_cache_object *object;
39};
40
41struct flow_cache_percpu {
42 struct hlist_head *hash_table;
43 int hash_count;
44 u32 hash_rnd;
45 int hash_rnd_recalc;
46 struct tasklet_struct flush_tasklet;
47};
48
49struct flow_flush_info {
50 struct flow_cache *cache;
51 atomic_t cpuleft;
52 struct completion completion;
53};
54
55struct flow_cache {
56 u32 hash_shift;
57 struct flow_cache_percpu __percpu *percpu;
58 struct notifier_block hotcpu_notifier;
59 int low_watermark;
60 int high_watermark;
61 struct timer_list rnd_timer;
62};
63
64atomic_t flow_cache_genid = ATOMIC_INIT(0);
65EXPORT_SYMBOL(flow_cache_genid);
66static struct flow_cache flow_cache_global;
67static struct kmem_cache *flow_cachep __read_mostly;
68
69static DEFINE_SPINLOCK(flow_cache_gc_lock);
70static LIST_HEAD(flow_cache_gc_list);
71
72#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
73#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
74
75static void flow_cache_new_hashrnd(unsigned long arg)
76{
77 struct flow_cache *fc = (void *) arg;
78 int i;
79
80 for_each_possible_cpu(i)
81 per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
82
83 fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
84 add_timer(&fc->rnd_timer);
85}
86
87static int flow_entry_valid(struct flow_cache_entry *fle)
88{
89 if (atomic_read(&flow_cache_genid) != fle->genid)
90 return 0;
91 if (fle->object && !fle->object->ops->check(fle->object))
92 return 0;
93 return 1;
94}
95
96static void flow_entry_kill(struct flow_cache_entry *fle)
97{
98 if (fle->object)
99 fle->object->ops->delete(fle->object);
100 kmem_cache_free(flow_cachep, fle);
101}
102
103static void flow_cache_gc_task(struct work_struct *work)
104{
105 struct list_head gc_list;
106 struct flow_cache_entry *fce, *n;
107
108 INIT_LIST_HEAD(&gc_list);
109 spin_lock_bh(&flow_cache_gc_lock);
110 list_splice_tail_init(&flow_cache_gc_list, &gc_list);
111 spin_unlock_bh(&flow_cache_gc_lock);
112
113 list_for_each_entry_safe(fce, n, &gc_list, u.gc_list)
114 flow_entry_kill(fce);
115}
116static DECLARE_WORK(flow_cache_gc_work, flow_cache_gc_task);
117
118static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
119 int deleted, struct list_head *gc_list)
120{
121 if (deleted) {
122 fcp->hash_count -= deleted;
123 spin_lock_bh(&flow_cache_gc_lock);
124 list_splice_tail(gc_list, &flow_cache_gc_list);
125 spin_unlock_bh(&flow_cache_gc_lock);
126 schedule_work(&flow_cache_gc_work);
127 }
128}
129
130static void __flow_cache_shrink(struct flow_cache *fc,
131 struct flow_cache_percpu *fcp,
132 int shrink_to)
133{
134 struct flow_cache_entry *fle;
135 struct hlist_node *entry, *tmp;
136 LIST_HEAD(gc_list);
137 int i, deleted = 0;
138
139 for (i = 0; i < flow_cache_hash_size(fc); i++) {
140 int saved = 0;
141
142 hlist_for_each_entry_safe(fle, entry, tmp,
143 &fcp->hash_table[i], u.hlist) {
144 if (saved < shrink_to &&
145 flow_entry_valid(fle)) {
146 saved++;
147 } else {
148 deleted++;
149 hlist_del(&fle->u.hlist);
150 list_add_tail(&fle->u.gc_list, &gc_list);
151 }
152 }
153 }
154
155 flow_cache_queue_garbage(fcp, deleted, &gc_list);
156}
157
158static void flow_cache_shrink(struct flow_cache *fc,
159 struct flow_cache_percpu *fcp)
160{
161 int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
162
163 __flow_cache_shrink(fc, fcp, shrink_to);
164}
165
166static void flow_new_hash_rnd(struct flow_cache *fc,
167 struct flow_cache_percpu *fcp)
168{
169 get_random_bytes(&fcp->hash_rnd, sizeof(u32));
170 fcp->hash_rnd_recalc = 0;
171 __flow_cache_shrink(fc, fcp, 0);
172}
173
174static u32 flow_hash_code(struct flow_cache *fc,
175 struct flow_cache_percpu *fcp,
176 const struct flowi *key,
177 size_t keysize)
178{
179 const u32 *k = (const u32 *) key;
180 const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);
181
182 return jhash2(k, length, fcp->hash_rnd)
183 & (flow_cache_hash_size(fc) - 1);
184}
185
186/* I hear what you're saying, use memcmp. But memcmp cannot make
187 * important assumptions that we can here, such as alignment.
188 */
189static int flow_key_compare(const struct flowi *key1, const struct flowi *key2,
190 size_t keysize)
191{
192 const flow_compare_t *k1, *k1_lim, *k2;
193
194 k1 = (const flow_compare_t *) key1;
195 k1_lim = k1 + keysize;
196
197 k2 = (const flow_compare_t *) key2;
198
199 do {
200 if (*k1++ != *k2++)
201 return 1;
202 } while (k1 < k1_lim);
203
204 return 0;
205}
206
207struct flow_cache_object *
208flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
209 flow_resolve_t resolver, void *ctx)
210{
211 struct flow_cache *fc = &flow_cache_global;
212 struct flow_cache_percpu *fcp;
213 struct flow_cache_entry *fle, *tfle;
214 struct hlist_node *entry;
215 struct flow_cache_object *flo;
216 size_t keysize;
217 unsigned int hash;
218
219 local_bh_disable();
220 fcp = this_cpu_ptr(fc->percpu);
221
222 fle = NULL;
223 flo = NULL;
224
225 keysize = flow_key_size(family);
226 if (!keysize)
227 goto nocache;
228
229 /* Packet really early in init? Making flow_cache_init a
230 * pre-smp initcall would solve this. --RR */
231 if (!fcp->hash_table)
232 goto nocache;
233
234 if (fcp->hash_rnd_recalc)
235 flow_new_hash_rnd(fc, fcp);
236
237 hash = flow_hash_code(fc, fcp, key, keysize);
238 hlist_for_each_entry(tfle, entry, &fcp->hash_table[hash], u.hlist) {
239 if (tfle->net == net &&
240 tfle->family == family &&
241 tfle->dir == dir &&
242 flow_key_compare(key, &tfle->key, keysize) == 0) {
243 fle = tfle;
244 break;
245 }
246 }
247
248 if (unlikely(!fle)) {
249 if (fcp->hash_count > fc->high_watermark)
250 flow_cache_shrink(fc, fcp);
251
252 fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
253 if (fle) {
254 fle->net = net;
255 fle->family = family;
256 fle->dir = dir;
257 memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));
258 fle->object = NULL;
259 hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
260 fcp->hash_count++;
261 }
262 } else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
263 flo = fle->object;
264 if (!flo)
265 goto ret_object;
266 flo = flo->ops->get(flo);
267 if (flo)
268 goto ret_object;
269 } else if (fle->object) {
270 flo = fle->object;
271 flo->ops->delete(flo);
272 fle->object = NULL;
273 }
274
275nocache:
276 flo = NULL;
277 if (fle) {
278 flo = fle->object;
279 fle->object = NULL;
280 }
281 flo = resolver(net, key, family, dir, flo, ctx);
282 if (fle) {
283 fle->genid = atomic_read(&flow_cache_genid);
284 if (!IS_ERR(flo))
285 fle->object = flo;
286 else
287 fle->genid--;
288 } else {
289 if (flo && !IS_ERR(flo))
290 flo->ops->delete(flo);
291 }
292ret_object:
293 local_bh_enable();
294 return flo;
295}
296EXPORT_SYMBOL(flow_cache_lookup);
297
298static void flow_cache_flush_tasklet(unsigned long data)
299{
300 struct flow_flush_info *info = (void *)data;
301 struct flow_cache *fc = info->cache;
302 struct flow_cache_percpu *fcp;
303 struct flow_cache_entry *fle;
304 struct hlist_node *entry, *tmp;
305 LIST_HEAD(gc_list);
306 int i, deleted = 0;
307
308 fcp = this_cpu_ptr(fc->percpu);
309 for (i = 0; i < flow_cache_hash_size(fc); i++) {
310 hlist_for_each_entry_safe(fle, entry, tmp,
311 &fcp->hash_table[i], u.hlist) {
312 if (flow_entry_valid(fle))
313 continue;
314
315 deleted++;
316 hlist_del(&fle->u.hlist);
317 list_add_tail(&fle->u.gc_list, &gc_list);
318 }
319 }
320
321 flow_cache_queue_garbage(fcp, deleted, &gc_list);
322
323 if (atomic_dec_and_test(&info->cpuleft))
324 complete(&info->completion);
325}
326
327static void flow_cache_flush_per_cpu(void *data)
328{
329 struct flow_flush_info *info = data;
330 int cpu;
331 struct tasklet_struct *tasklet;
332
333 cpu = smp_processor_id();
334 tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
335 tasklet->data = (unsigned long)info;
336 tasklet_schedule(tasklet);
337}
338
339void flow_cache_flush(void)
340{
341 struct flow_flush_info info;
342 static DEFINE_MUTEX(flow_flush_sem);
343
344 /* Don't want cpus going down or up during this. */
345 get_online_cpus();
346 mutex_lock(&flow_flush_sem);
347 info.cache = &flow_cache_global;
348 atomic_set(&info.cpuleft, num_online_cpus());
349 init_completion(&info.completion);
350
351 local_bh_disable();
352 smp_call_function(flow_cache_flush_per_cpu, &info, 0);
353 flow_cache_flush_tasklet((unsigned long)&info);
354 local_bh_enable();
355
356 wait_for_completion(&info.completion);
357 mutex_unlock(&flow_flush_sem);
358 put_online_cpus();
359}
360
361static int __cpuinit flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
362{
363 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
364 size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);
365
366 if (!fcp->hash_table) {
367 fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
368 if (!fcp->hash_table) {
369 pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
370 return -ENOMEM;
371 }
372 fcp->hash_rnd_recalc = 1;
373 fcp->hash_count = 0;
374 tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
375 }
376 return 0;
377}
378
379static int __cpuinit flow_cache_cpu(struct notifier_block *nfb,
380 unsigned long action,
381 void *hcpu)
382{
383 struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
384 int res, cpu = (unsigned long) hcpu;
385 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
386
387 switch (action) {
388 case CPU_UP_PREPARE:
389 case CPU_UP_PREPARE_FROZEN:
390 res = flow_cache_cpu_prepare(fc, cpu);
391 if (res)
392 return notifier_from_errno(res);
393 break;
394 case CPU_DEAD:
395 case CPU_DEAD_FROZEN:
396 __flow_cache_shrink(fc, fcp, 0);
397 break;
398 }
399 return NOTIFY_OK;
400}
401
402static int __init flow_cache_init(struct flow_cache *fc)
403{
404 int i;
405
406 fc->hash_shift = 10;
407 fc->low_watermark = 2 * flow_cache_hash_size(fc);
408 fc->high_watermark = 4 * flow_cache_hash_size(fc);
409
410 fc->percpu = alloc_percpu(struct flow_cache_percpu);
411 if (!fc->percpu)
412 return -ENOMEM;
413
414 for_each_online_cpu(i) {
415 if (flow_cache_cpu_prepare(fc, i))
416 return -ENOMEM;
417 }
418 fc->hotcpu_notifier = (struct notifier_block){
419 .notifier_call = flow_cache_cpu,
420 };
421 register_hotcpu_notifier(&fc->hotcpu_notifier);
422
423 setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
424 (unsigned long) fc);
425 fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
426 add_timer(&fc->rnd_timer);
427
428 return 0;
429}
430
431static int __init flow_cache_init_global(void)
432{
433 flow_cachep = kmem_cache_create("flow_cache",
434 sizeof(struct flow_cache_entry),
435 0, SLAB_PANIC, NULL);
436
437 return flow_cache_init(&flow_cache_global);
438}
439
440module_init(flow_cache_init_global);
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>
23#include <linux/mutex.h>
24#include <net/flow.h>
25#include <linux/atomic.h>
26#include <linux/security.h>
27#include <net/net_namespace.h>
28
29struct flow_cache_entry {
30 union {
31 struct hlist_node hlist;
32 struct list_head gc_list;
33 } u;
34 struct net *net;
35 u16 family;
36 u8 dir;
37 u32 genid;
38 struct flowi key;
39 struct flow_cache_object *object;
40};
41
42struct flow_flush_info {
43 struct flow_cache *cache;
44 atomic_t cpuleft;
45 struct completion completion;
46};
47
48static struct kmem_cache *flow_cachep __read_mostly;
49
50#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
51#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
52
53static void flow_cache_new_hashrnd(unsigned long arg)
54{
55 struct flow_cache *fc = (void *) arg;
56 int i;
57
58 for_each_possible_cpu(i)
59 per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
60
61 fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
62 add_timer(&fc->rnd_timer);
63}
64
65static int flow_entry_valid(struct flow_cache_entry *fle,
66 struct netns_xfrm *xfrm)
67{
68 if (atomic_read(&xfrm->flow_cache_genid) != fle->genid)
69 return 0;
70 if (fle->object && !fle->object->ops->check(fle->object))
71 return 0;
72 return 1;
73}
74
75static void flow_entry_kill(struct flow_cache_entry *fle,
76 struct netns_xfrm *xfrm)
77{
78 if (fle->object)
79 fle->object->ops->delete(fle->object);
80 kmem_cache_free(flow_cachep, fle);
81}
82
83static void flow_cache_gc_task(struct work_struct *work)
84{
85 struct list_head gc_list;
86 struct flow_cache_entry *fce, *n;
87 struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
88 flow_cache_gc_work);
89
90 INIT_LIST_HEAD(&gc_list);
91 spin_lock_bh(&xfrm->flow_cache_gc_lock);
92 list_splice_tail_init(&xfrm->flow_cache_gc_list, &gc_list);
93 spin_unlock_bh(&xfrm->flow_cache_gc_lock);
94
95 list_for_each_entry_safe(fce, n, &gc_list, u.gc_list)
96 flow_entry_kill(fce, xfrm);
97}
98
99static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
100 int deleted, struct list_head *gc_list,
101 struct netns_xfrm *xfrm)
102{
103 if (deleted) {
104 fcp->hash_count -= deleted;
105 spin_lock_bh(&xfrm->flow_cache_gc_lock);
106 list_splice_tail(gc_list, &xfrm->flow_cache_gc_list);
107 spin_unlock_bh(&xfrm->flow_cache_gc_lock);
108 schedule_work(&xfrm->flow_cache_gc_work);
109 }
110}
111
112static void __flow_cache_shrink(struct flow_cache *fc,
113 struct flow_cache_percpu *fcp,
114 int shrink_to)
115{
116 struct flow_cache_entry *fle;
117 struct hlist_node *tmp;
118 LIST_HEAD(gc_list);
119 int i, deleted = 0;
120 struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
121 flow_cache_global);
122
123 for (i = 0; i < flow_cache_hash_size(fc); i++) {
124 int saved = 0;
125
126 hlist_for_each_entry_safe(fle, tmp,
127 &fcp->hash_table[i], u.hlist) {
128 if (saved < shrink_to &&
129 flow_entry_valid(fle, xfrm)) {
130 saved++;
131 } else {
132 deleted++;
133 hlist_del(&fle->u.hlist);
134 list_add_tail(&fle->u.gc_list, &gc_list);
135 }
136 }
137 }
138
139 flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
140}
141
142static void flow_cache_shrink(struct flow_cache *fc,
143 struct flow_cache_percpu *fcp)
144{
145 int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
146
147 __flow_cache_shrink(fc, fcp, shrink_to);
148}
149
150static void flow_new_hash_rnd(struct flow_cache *fc,
151 struct flow_cache_percpu *fcp)
152{
153 get_random_bytes(&fcp->hash_rnd, sizeof(u32));
154 fcp->hash_rnd_recalc = 0;
155 __flow_cache_shrink(fc, fcp, 0);
156}
157
158static u32 flow_hash_code(struct flow_cache *fc,
159 struct flow_cache_percpu *fcp,
160 const struct flowi *key,
161 size_t keysize)
162{
163 const u32 *k = (const u32 *) key;
164 const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);
165
166 return jhash2(k, length, fcp->hash_rnd)
167 & (flow_cache_hash_size(fc) - 1);
168}
169
170/* I hear what you're saying, use memcmp. But memcmp cannot make
171 * important assumptions that we can here, such as alignment.
172 */
173static int flow_key_compare(const struct flowi *key1, const struct flowi *key2,
174 size_t keysize)
175{
176 const flow_compare_t *k1, *k1_lim, *k2;
177
178 k1 = (const flow_compare_t *) key1;
179 k1_lim = k1 + keysize;
180
181 k2 = (const flow_compare_t *) key2;
182
183 do {
184 if (*k1++ != *k2++)
185 return 1;
186 } while (k1 < k1_lim);
187
188 return 0;
189}
190
191struct flow_cache_object *
192flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
193 flow_resolve_t resolver, void *ctx)
194{
195 struct flow_cache *fc = &net->xfrm.flow_cache_global;
196 struct flow_cache_percpu *fcp;
197 struct flow_cache_entry *fle, *tfle;
198 struct flow_cache_object *flo;
199 size_t keysize;
200 unsigned int hash;
201
202 local_bh_disable();
203 fcp = this_cpu_ptr(fc->percpu);
204
205 fle = NULL;
206 flo = NULL;
207
208 keysize = flow_key_size(family);
209 if (!keysize)
210 goto nocache;
211
212 /* Packet really early in init? Making flow_cache_init a
213 * pre-smp initcall would solve this. --RR */
214 if (!fcp->hash_table)
215 goto nocache;
216
217 if (fcp->hash_rnd_recalc)
218 flow_new_hash_rnd(fc, fcp);
219
220 hash = flow_hash_code(fc, fcp, key, keysize);
221 hlist_for_each_entry(tfle, &fcp->hash_table[hash], u.hlist) {
222 if (tfle->net == net &&
223 tfle->family == family &&
224 tfle->dir == dir &&
225 flow_key_compare(key, &tfle->key, keysize) == 0) {
226 fle = tfle;
227 break;
228 }
229 }
230
231 if (unlikely(!fle)) {
232 if (fcp->hash_count > fc->high_watermark)
233 flow_cache_shrink(fc, fcp);
234
235 fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
236 if (fle) {
237 fle->net = net;
238 fle->family = family;
239 fle->dir = dir;
240 memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));
241 fle->object = NULL;
242 hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
243 fcp->hash_count++;
244 }
245 } else if (likely(fle->genid == atomic_read(&net->xfrm.flow_cache_genid))) {
246 flo = fle->object;
247 if (!flo)
248 goto ret_object;
249 flo = flo->ops->get(flo);
250 if (flo)
251 goto ret_object;
252 } else if (fle->object) {
253 flo = fle->object;
254 flo->ops->delete(flo);
255 fle->object = NULL;
256 }
257
258nocache:
259 flo = NULL;
260 if (fle) {
261 flo = fle->object;
262 fle->object = NULL;
263 }
264 flo = resolver(net, key, family, dir, flo, ctx);
265 if (fle) {
266 fle->genid = atomic_read(&net->xfrm.flow_cache_genid);
267 if (!IS_ERR(flo))
268 fle->object = flo;
269 else
270 fle->genid--;
271 } else {
272 if (!IS_ERR_OR_NULL(flo))
273 flo->ops->delete(flo);
274 }
275ret_object:
276 local_bh_enable();
277 return flo;
278}
279EXPORT_SYMBOL(flow_cache_lookup);
280
281static void flow_cache_flush_tasklet(unsigned long data)
282{
283 struct flow_flush_info *info = (void *)data;
284 struct flow_cache *fc = info->cache;
285 struct flow_cache_percpu *fcp;
286 struct flow_cache_entry *fle;
287 struct hlist_node *tmp;
288 LIST_HEAD(gc_list);
289 int i, deleted = 0;
290 struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
291 flow_cache_global);
292
293 fcp = this_cpu_ptr(fc->percpu);
294 for (i = 0; i < flow_cache_hash_size(fc); i++) {
295 hlist_for_each_entry_safe(fle, tmp,
296 &fcp->hash_table[i], u.hlist) {
297 if (flow_entry_valid(fle, xfrm))
298 continue;
299
300 deleted++;
301 hlist_del(&fle->u.hlist);
302 list_add_tail(&fle->u.gc_list, &gc_list);
303 }
304 }
305
306 flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
307
308 if (atomic_dec_and_test(&info->cpuleft))
309 complete(&info->completion);
310}
311
312/*
313 * Return whether a cpu needs flushing. Conservatively, we assume
314 * the presence of any entries means the core may require flushing,
315 * since the flow_cache_ops.check() function may assume it's running
316 * on the same core as the per-cpu cache component.
317 */
318static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu)
319{
320 struct flow_cache_percpu *fcp;
321 int i;
322
323 fcp = per_cpu_ptr(fc->percpu, cpu);
324 for (i = 0; i < flow_cache_hash_size(fc); i++)
325 if (!hlist_empty(&fcp->hash_table[i]))
326 return 0;
327 return 1;
328}
329
330static void flow_cache_flush_per_cpu(void *data)
331{
332 struct flow_flush_info *info = data;
333 struct tasklet_struct *tasklet;
334
335 tasklet = &this_cpu_ptr(info->cache->percpu)->flush_tasklet;
336 tasklet->data = (unsigned long)info;
337 tasklet_schedule(tasklet);
338}
339
340void flow_cache_flush(struct net *net)
341{
342 struct flow_flush_info info;
343 cpumask_var_t mask;
344 int i, self;
345
346 /* Track which cpus need flushing to avoid disturbing all cores. */
347 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
348 return;
349 cpumask_clear(mask);
350
351 /* Don't want cpus going down or up during this. */
352 get_online_cpus();
353 mutex_lock(&net->xfrm.flow_flush_sem);
354 info.cache = &net->xfrm.flow_cache_global;
355 for_each_online_cpu(i)
356 if (!flow_cache_percpu_empty(info.cache, i))
357 cpumask_set_cpu(i, mask);
358 atomic_set(&info.cpuleft, cpumask_weight(mask));
359 if (atomic_read(&info.cpuleft) == 0)
360 goto done;
361
362 init_completion(&info.completion);
363
364 local_bh_disable();
365 self = cpumask_test_and_clear_cpu(smp_processor_id(), mask);
366 on_each_cpu_mask(mask, flow_cache_flush_per_cpu, &info, 0);
367 if (self)
368 flow_cache_flush_tasklet((unsigned long)&info);
369 local_bh_enable();
370
371 wait_for_completion(&info.completion);
372
373done:
374 mutex_unlock(&net->xfrm.flow_flush_sem);
375 put_online_cpus();
376 free_cpumask_var(mask);
377}
378
379static void flow_cache_flush_task(struct work_struct *work)
380{
381 struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
382 flow_cache_gc_work);
383 struct net *net = container_of(xfrm, struct net, xfrm);
384
385 flow_cache_flush(net);
386}
387
388void flow_cache_flush_deferred(struct net *net)
389{
390 schedule_work(&net->xfrm.flow_cache_flush_work);
391}
392
393static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
394{
395 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
396 size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);
397
398 if (!fcp->hash_table) {
399 fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
400 if (!fcp->hash_table) {
401 pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
402 return -ENOMEM;
403 }
404 fcp->hash_rnd_recalc = 1;
405 fcp->hash_count = 0;
406 tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
407 }
408 return 0;
409}
410
411static int flow_cache_cpu(struct notifier_block *nfb,
412 unsigned long action,
413 void *hcpu)
414{
415 struct flow_cache *fc = container_of(nfb, struct flow_cache,
416 hotcpu_notifier);
417 int res, cpu = (unsigned long) hcpu;
418 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
419
420 switch (action) {
421 case CPU_UP_PREPARE:
422 case CPU_UP_PREPARE_FROZEN:
423 res = flow_cache_cpu_prepare(fc, cpu);
424 if (res)
425 return notifier_from_errno(res);
426 break;
427 case CPU_DEAD:
428 case CPU_DEAD_FROZEN:
429 __flow_cache_shrink(fc, fcp, 0);
430 break;
431 }
432 return NOTIFY_OK;
433}
434
435int flow_cache_init(struct net *net)
436{
437 int i;
438 struct flow_cache *fc = &net->xfrm.flow_cache_global;
439
440 if (!flow_cachep)
441 flow_cachep = kmem_cache_create("flow_cache",
442 sizeof(struct flow_cache_entry),
443 0, SLAB_PANIC, NULL);
444 spin_lock_init(&net->xfrm.flow_cache_gc_lock);
445 INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
446 INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);
447 INIT_WORK(&net->xfrm.flow_cache_flush_work, flow_cache_flush_task);
448 mutex_init(&net->xfrm.flow_flush_sem);
449
450 fc->hash_shift = 10;
451 fc->low_watermark = 2 * flow_cache_hash_size(fc);
452 fc->high_watermark = 4 * flow_cache_hash_size(fc);
453
454 fc->percpu = alloc_percpu(struct flow_cache_percpu);
455 if (!fc->percpu)
456 return -ENOMEM;
457
458 cpu_notifier_register_begin();
459
460 for_each_online_cpu(i) {
461 if (flow_cache_cpu_prepare(fc, i))
462 goto err;
463 }
464 fc->hotcpu_notifier = (struct notifier_block){
465 .notifier_call = flow_cache_cpu,
466 };
467 __register_hotcpu_notifier(&fc->hotcpu_notifier);
468
469 cpu_notifier_register_done();
470
471 setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
472 (unsigned long) fc);
473 fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
474 add_timer(&fc->rnd_timer);
475
476 return 0;
477
478err:
479 for_each_possible_cpu(i) {
480 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
481 kfree(fcp->hash_table);
482 fcp->hash_table = NULL;
483 }
484
485 cpu_notifier_register_done();
486
487 free_percpu(fc->percpu);
488 fc->percpu = NULL;
489
490 return -ENOMEM;
491}
492EXPORT_SYMBOL(flow_cache_init);
493
494void flow_cache_fini(struct net *net)
495{
496 int i;
497 struct flow_cache *fc = &net->xfrm.flow_cache_global;
498
499 del_timer_sync(&fc->rnd_timer);
500 unregister_hotcpu_notifier(&fc->hotcpu_notifier);
501
502 for_each_possible_cpu(i) {
503 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
504 kfree(fcp->hash_table);
505 fcp->hash_table = NULL;
506 }
507
508 free_percpu(fc->percpu);
509 fc->percpu = NULL;
510}
511EXPORT_SYMBOL(flow_cache_fini);