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Linux/net/openvswitch/flow_table.c

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  1 /*
  2  * Copyright (c) 2007-2014 Nicira, Inc.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of version 2 of the GNU General Public
  6  * License as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful, but
  9  * WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public License
 14  * along with this program; if not, write to the Free Software
 15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 16  * 02110-1301, USA
 17  */
 18 
 19 #include "flow.h"
 20 #include "datapath.h"
 21 #include <linux/uaccess.h>
 22 #include <linux/netdevice.h>
 23 #include <linux/etherdevice.h>
 24 #include <linux/if_ether.h>
 25 #include <linux/if_vlan.h>
 26 #include <net/llc_pdu.h>
 27 #include <linux/kernel.h>
 28 #include <linux/jhash.h>
 29 #include <linux/jiffies.h>
 30 #include <linux/llc.h>
 31 #include <linux/module.h>
 32 #include <linux/in.h>
 33 #include <linux/rcupdate.h>
 34 #include <linux/if_arp.h>
 35 #include <linux/ip.h>
 36 #include <linux/ipv6.h>
 37 #include <linux/sctp.h>
 38 #include <linux/tcp.h>
 39 #include <linux/udp.h>
 40 #include <linux/icmp.h>
 41 #include <linux/icmpv6.h>
 42 #include <linux/rculist.h>
 43 #include <net/ip.h>
 44 #include <net/ipv6.h>
 45 #include <net/ndisc.h>
 46 
 47 #define TBL_MIN_BUCKETS         1024
 48 #define REHASH_INTERVAL         (10 * 60 * HZ)
 49 
 50 static struct kmem_cache *flow_cache;
 51 struct kmem_cache *flow_stats_cache __read_mostly;
 52 
 53 static u16 range_n_bytes(const struct sw_flow_key_range *range)
 54 {
 55         return range->end - range->start;
 56 }
 57 
 58 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
 59                        bool full, const struct sw_flow_mask *mask)
 60 {
 61         int start = full ? 0 : mask->range.start;
 62         int len = full ? sizeof *dst : range_n_bytes(&mask->range);
 63         const long *m = (const long *)((const u8 *)&mask->key + start);
 64         const long *s = (const long *)((const u8 *)src + start);
 65         long *d = (long *)((u8 *)dst + start);
 66         int i;
 67 
 68         /* If 'full' is true then all of 'dst' is fully initialized. Otherwise,
 69          * if 'full' is false the memory outside of the 'mask->range' is left
 70          * uninitialized. This can be used as an optimization when further
 71          * operations on 'dst' only use contents within 'mask->range'.
 72          */
 73         for (i = 0; i < len; i += sizeof(long))
 74                 *d++ = *s++ & *m++;
 75 }
 76 
 77 struct sw_flow *ovs_flow_alloc(void)
 78 {
 79         struct sw_flow *flow;
 80         struct flow_stats *stats;
 81         int node;
 82 
 83         flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
 84         if (!flow)
 85                 return ERR_PTR(-ENOMEM);
 86 
 87         flow->sf_acts = NULL;
 88         flow->mask = NULL;
 89         flow->id.unmasked_key = NULL;
 90         flow->id.ufid_len = 0;
 91         flow->stats_last_writer = NUMA_NO_NODE;
 92 
 93         /* Initialize the default stat node. */
 94         stats = kmem_cache_alloc_node(flow_stats_cache,
 95                                       GFP_KERNEL | __GFP_ZERO,
 96                                       node_online(0) ? 0 : NUMA_NO_NODE);
 97         if (!stats)
 98                 goto err;
 99 
100         spin_lock_init(&stats->lock);
101 
102         RCU_INIT_POINTER(flow->stats[0], stats);
103 
104         for_each_node(node)
105                 if (node != 0)
106                         RCU_INIT_POINTER(flow->stats[node], NULL);
107 
108         return flow;
109 err:
110         kmem_cache_free(flow_cache, flow);
111         return ERR_PTR(-ENOMEM);
112 }
113 
114 int ovs_flow_tbl_count(const struct flow_table *table)
115 {
116         return table->count;
117 }
118 
119 static struct flex_array *alloc_buckets(unsigned int n_buckets)
120 {
121         struct flex_array *buckets;
122         int i, err;
123 
124         buckets = flex_array_alloc(sizeof(struct hlist_head),
125                                    n_buckets, GFP_KERNEL);
126         if (!buckets)
127                 return NULL;
128 
129         err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
130         if (err) {
131                 flex_array_free(buckets);
132                 return NULL;
133         }
134 
135         for (i = 0; i < n_buckets; i++)
136                 INIT_HLIST_HEAD((struct hlist_head *)
137                                         flex_array_get(buckets, i));
138 
139         return buckets;
140 }
141 
142 static void flow_free(struct sw_flow *flow)
143 {
144         int node;
145 
146         if (ovs_identifier_is_key(&flow->id))
147                 kfree(flow->id.unmasked_key);
148         kfree((struct sw_flow_actions __force *)flow->sf_acts);
149         for_each_node(node)
150                 if (flow->stats[node])
151                         kmem_cache_free(flow_stats_cache,
152                                         (struct flow_stats __force *)flow->stats[node]);
153         kmem_cache_free(flow_cache, flow);
154 }
155 
156 static void rcu_free_flow_callback(struct rcu_head *rcu)
157 {
158         struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
159 
160         flow_free(flow);
161 }
162 
163 void ovs_flow_free(struct sw_flow *flow, bool deferred)
164 {
165         if (!flow)
166                 return;
167 
168         if (deferred)
169                 call_rcu(&flow->rcu, rcu_free_flow_callback);
170         else
171                 flow_free(flow);
172 }
173 
174 static void free_buckets(struct flex_array *buckets)
175 {
176         flex_array_free(buckets);
177 }
178 
179 
180 static void __table_instance_destroy(struct table_instance *ti)
181 {
182         free_buckets(ti->buckets);
183         kfree(ti);
184 }
185 
186 static struct table_instance *table_instance_alloc(int new_size)
187 {
188         struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
189 
190         if (!ti)
191                 return NULL;
192 
193         ti->buckets = alloc_buckets(new_size);
194 
195         if (!ti->buckets) {
196                 kfree(ti);
197                 return NULL;
198         }
199         ti->n_buckets = new_size;
200         ti->node_ver = 0;
201         ti->keep_flows = false;
202         get_random_bytes(&ti->hash_seed, sizeof(u32));
203 
204         return ti;
205 }
206 
207 int ovs_flow_tbl_init(struct flow_table *table)
208 {
209         struct table_instance *ti, *ufid_ti;
210 
211         ti = table_instance_alloc(TBL_MIN_BUCKETS);
212 
213         if (!ti)
214                 return -ENOMEM;
215 
216         ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
217         if (!ufid_ti)
218                 goto free_ti;
219 
220         rcu_assign_pointer(table->ti, ti);
221         rcu_assign_pointer(table->ufid_ti, ufid_ti);
222         INIT_LIST_HEAD(&table->mask_list);
223         table->last_rehash = jiffies;
224         table->count = 0;
225         table->ufid_count = 0;
226         return 0;
227 
228 free_ti:
229         __table_instance_destroy(ti);
230         return -ENOMEM;
231 }
232 
233 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
234 {
235         struct table_instance *ti = container_of(rcu, struct table_instance, rcu);
236 
237         __table_instance_destroy(ti);
238 }
239 
240 static void table_instance_destroy(struct table_instance *ti,
241                                    struct table_instance *ufid_ti,
242                                    bool deferred)
243 {
244         int i;
245 
246         if (!ti)
247                 return;
248 
249         BUG_ON(!ufid_ti);
250         if (ti->keep_flows)
251                 goto skip_flows;
252 
253         for (i = 0; i < ti->n_buckets; i++) {
254                 struct sw_flow *flow;
255                 struct hlist_head *head = flex_array_get(ti->buckets, i);
256                 struct hlist_node *n;
257                 int ver = ti->node_ver;
258                 int ufid_ver = ufid_ti->node_ver;
259 
260                 hlist_for_each_entry_safe(flow, n, head, flow_table.node[ver]) {
261                         hlist_del_rcu(&flow->flow_table.node[ver]);
262                         if (ovs_identifier_is_ufid(&flow->id))
263                                 hlist_del_rcu(&flow->ufid_table.node[ufid_ver]);
264                         ovs_flow_free(flow, deferred);
265                 }
266         }
267 
268 skip_flows:
269         if (deferred) {
270                 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
271                 call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb);
272         } else {
273                 __table_instance_destroy(ti);
274                 __table_instance_destroy(ufid_ti);
275         }
276 }
277 
278 /* No need for locking this function is called from RCU callback or
279  * error path.
280  */
281 void ovs_flow_tbl_destroy(struct flow_table *table)
282 {
283         struct table_instance *ti = rcu_dereference_raw(table->ti);
284         struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
285 
286         table_instance_destroy(ti, ufid_ti, false);
287 }
288 
289 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
290                                        u32 *bucket, u32 *last)
291 {
292         struct sw_flow *flow;
293         struct hlist_head *head;
294         int ver;
295         int i;
296 
297         ver = ti->node_ver;
298         while (*bucket < ti->n_buckets) {
299                 i = 0;
300                 head = flex_array_get(ti->buckets, *bucket);
301                 hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) {
302                         if (i < *last) {
303                                 i++;
304                                 continue;
305                         }
306                         *last = i + 1;
307                         return flow;
308                 }
309                 (*bucket)++;
310                 *last = 0;
311         }
312 
313         return NULL;
314 }
315 
316 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash)
317 {
318         hash = jhash_1word(hash, ti->hash_seed);
319         return flex_array_get(ti->buckets,
320                                 (hash & (ti->n_buckets - 1)));
321 }
322 
323 static void table_instance_insert(struct table_instance *ti,
324                                   struct sw_flow *flow)
325 {
326         struct hlist_head *head;
327 
328         head = find_bucket(ti, flow->flow_table.hash);
329         hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head);
330 }
331 
332 static void ufid_table_instance_insert(struct table_instance *ti,
333                                        struct sw_flow *flow)
334 {
335         struct hlist_head *head;
336 
337         head = find_bucket(ti, flow->ufid_table.hash);
338         hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head);
339 }
340 
341 static void flow_table_copy_flows(struct table_instance *old,
342                                   struct table_instance *new, bool ufid)
343 {
344         int old_ver;
345         int i;
346 
347         old_ver = old->node_ver;
348         new->node_ver = !old_ver;
349 
350         /* Insert in new table. */
351         for (i = 0; i < old->n_buckets; i++) {
352                 struct sw_flow *flow;
353                 struct hlist_head *head;
354 
355                 head = flex_array_get(old->buckets, i);
356 
357                 if (ufid)
358                         hlist_for_each_entry(flow, head,
359                                              ufid_table.node[old_ver])
360                                 ufid_table_instance_insert(new, flow);
361                 else
362                         hlist_for_each_entry(flow, head,
363                                              flow_table.node[old_ver])
364                                 table_instance_insert(new, flow);
365         }
366 
367         old->keep_flows = true;
368 }
369 
370 static struct table_instance *table_instance_rehash(struct table_instance *ti,
371                                                     int n_buckets, bool ufid)
372 {
373         struct table_instance *new_ti;
374 
375         new_ti = table_instance_alloc(n_buckets);
376         if (!new_ti)
377                 return NULL;
378 
379         flow_table_copy_flows(ti, new_ti, ufid);
380 
381         return new_ti;
382 }
383 
384 int ovs_flow_tbl_flush(struct flow_table *flow_table)
385 {
386         struct table_instance *old_ti, *new_ti;
387         struct table_instance *old_ufid_ti, *new_ufid_ti;
388 
389         new_ti = table_instance_alloc(TBL_MIN_BUCKETS);
390         if (!new_ti)
391                 return -ENOMEM;
392         new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
393         if (!new_ufid_ti)
394                 goto err_free_ti;
395 
396         old_ti = ovsl_dereference(flow_table->ti);
397         old_ufid_ti = ovsl_dereference(flow_table->ufid_ti);
398 
399         rcu_assign_pointer(flow_table->ti, new_ti);
400         rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti);
401         flow_table->last_rehash = jiffies;
402         flow_table->count = 0;
403         flow_table->ufid_count = 0;
404 
405         table_instance_destroy(old_ti, old_ufid_ti, true);
406         return 0;
407 
408 err_free_ti:
409         __table_instance_destroy(new_ti);
410         return -ENOMEM;
411 }
412 
413 static u32 flow_hash(const struct sw_flow_key *key,
414                      const struct sw_flow_key_range *range)
415 {
416         int key_start = range->start;
417         int key_end = range->end;
418         const u32 *hash_key = (const u32 *)((const u8 *)key + key_start);
419         int hash_u32s = (key_end - key_start) >> 2;
420 
421         /* Make sure number of hash bytes are multiple of u32. */
422         BUILD_BUG_ON(sizeof(long) % sizeof(u32));
423 
424         return jhash2(hash_key, hash_u32s, 0);
425 }
426 
427 static int flow_key_start(const struct sw_flow_key *key)
428 {
429         if (key->tun_key.ipv4_dst)
430                 return 0;
431         else
432                 return rounddown(offsetof(struct sw_flow_key, phy),
433                                           sizeof(long));
434 }
435 
436 static bool cmp_key(const struct sw_flow_key *key1,
437                     const struct sw_flow_key *key2,
438                     int key_start, int key_end)
439 {
440         const long *cp1 = (const long *)((const u8 *)key1 + key_start);
441         const long *cp2 = (const long *)((const u8 *)key2 + key_start);
442         long diffs = 0;
443         int i;
444 
445         for (i = key_start; i < key_end;  i += sizeof(long))
446                 diffs |= *cp1++ ^ *cp2++;
447 
448         return diffs == 0;
449 }
450 
451 static bool flow_cmp_masked_key(const struct sw_flow *flow,
452                                 const struct sw_flow_key *key,
453                                 const struct sw_flow_key_range *range)
454 {
455         return cmp_key(&flow->key, key, range->start, range->end);
456 }
457 
458 static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
459                                       const struct sw_flow_match *match)
460 {
461         struct sw_flow_key *key = match->key;
462         int key_start = flow_key_start(key);
463         int key_end = match->range.end;
464 
465         BUG_ON(ovs_identifier_is_ufid(&flow->id));
466         return cmp_key(flow->id.unmasked_key, key, key_start, key_end);
467 }
468 
469 static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
470                                           const struct sw_flow_key *unmasked,
471                                           const struct sw_flow_mask *mask)
472 {
473         struct sw_flow *flow;
474         struct hlist_head *head;
475         u32 hash;
476         struct sw_flow_key masked_key;
477 
478         ovs_flow_mask_key(&masked_key, unmasked, false, mask);
479         hash = flow_hash(&masked_key, &mask->range);
480         head = find_bucket(ti, hash);
481         hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver]) {
482                 if (flow->mask == mask && flow->flow_table.hash == hash &&
483                     flow_cmp_masked_key(flow, &masked_key, &mask->range))
484                         return flow;
485         }
486         return NULL;
487 }
488 
489 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
490                                     const struct sw_flow_key *key,
491                                     u32 *n_mask_hit)
492 {
493         struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
494         struct sw_flow_mask *mask;
495         struct sw_flow *flow;
496 
497         *n_mask_hit = 0;
498         list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
499                 (*n_mask_hit)++;
500                 flow = masked_flow_lookup(ti, key, mask);
501                 if (flow)  /* Found */
502                         return flow;
503         }
504         return NULL;
505 }
506 
507 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
508                                     const struct sw_flow_key *key)
509 {
510         u32 __always_unused n_mask_hit;
511 
512         return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
513 }
514 
515 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
516                                           const struct sw_flow_match *match)
517 {
518         struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
519         struct sw_flow_mask *mask;
520         struct sw_flow *flow;
521 
522         /* Always called under ovs-mutex. */
523         list_for_each_entry(mask, &tbl->mask_list, list) {
524                 flow = masked_flow_lookup(ti, match->key, mask);
525                 if (flow && ovs_identifier_is_key(&flow->id) &&
526                     ovs_flow_cmp_unmasked_key(flow, match))
527                         return flow;
528         }
529         return NULL;
530 }
531 
532 static u32 ufid_hash(const struct sw_flow_id *sfid)
533 {
534         return jhash(sfid->ufid, sfid->ufid_len, 0);
535 }
536 
537 static bool ovs_flow_cmp_ufid(const struct sw_flow *flow,
538                               const struct sw_flow_id *sfid)
539 {
540         if (flow->id.ufid_len != sfid->ufid_len)
541                 return false;
542 
543         return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len);
544 }
545 
546 bool ovs_flow_cmp(const struct sw_flow *flow, const struct sw_flow_match *match)
547 {
548         if (ovs_identifier_is_ufid(&flow->id))
549                 return flow_cmp_masked_key(flow, match->key, &match->range);
550 
551         return ovs_flow_cmp_unmasked_key(flow, match);
552 }
553 
554 struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,
555                                          const struct sw_flow_id *ufid)
556 {
557         struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti);
558         struct sw_flow *flow;
559         struct hlist_head *head;
560         u32 hash;
561 
562         hash = ufid_hash(ufid);
563         head = find_bucket(ti, hash);
564         hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver]) {
565                 if (flow->ufid_table.hash == hash &&
566                     ovs_flow_cmp_ufid(flow, ufid))
567                         return flow;
568         }
569         return NULL;
570 }
571 
572 int ovs_flow_tbl_num_masks(const struct flow_table *table)
573 {
574         struct sw_flow_mask *mask;
575         int num = 0;
576 
577         list_for_each_entry(mask, &table->mask_list, list)
578                 num++;
579 
580         return num;
581 }
582 
583 static struct table_instance *table_instance_expand(struct table_instance *ti,
584                                                     bool ufid)
585 {
586         return table_instance_rehash(ti, ti->n_buckets * 2, ufid);
587 }
588 
589 /* Remove 'mask' from the mask list, if it is not needed any more. */
590 static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
591 {
592         if (mask) {
593                 /* ovs-lock is required to protect mask-refcount and
594                  * mask list.
595                  */
596                 ASSERT_OVSL();
597                 BUG_ON(!mask->ref_count);
598                 mask->ref_count--;
599 
600                 if (!mask->ref_count) {
601                         list_del_rcu(&mask->list);
602                         kfree_rcu(mask, rcu);
603                 }
604         }
605 }
606 
607 /* Must be called with OVS mutex held. */
608 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
609 {
610         struct table_instance *ti = ovsl_dereference(table->ti);
611         struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);
612 
613         BUG_ON(table->count == 0);
614         hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
615         table->count--;
616         if (ovs_identifier_is_ufid(&flow->id)) {
617                 hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
618                 table->ufid_count--;
619         }
620 
621         /* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
622          * accessible as long as the RCU read lock is held.
623          */
624         flow_mask_remove(table, flow->mask);
625 }
626 
627 static struct sw_flow_mask *mask_alloc(void)
628 {
629         struct sw_flow_mask *mask;
630 
631         mask = kmalloc(sizeof(*mask), GFP_KERNEL);
632         if (mask)
633                 mask->ref_count = 1;
634 
635         return mask;
636 }
637 
638 static bool mask_equal(const struct sw_flow_mask *a,
639                        const struct sw_flow_mask *b)
640 {
641         const u8 *a_ = (const u8 *)&a->key + a->range.start;
642         const u8 *b_ = (const u8 *)&b->key + b->range.start;
643 
644         return  (a->range.end == b->range.end)
645                 && (a->range.start == b->range.start)
646                 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
647 }
648 
649 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
650                                            const struct sw_flow_mask *mask)
651 {
652         struct list_head *ml;
653 
654         list_for_each(ml, &tbl->mask_list) {
655                 struct sw_flow_mask *m;
656                 m = container_of(ml, struct sw_flow_mask, list);
657                 if (mask_equal(mask, m))
658                         return m;
659         }
660 
661         return NULL;
662 }
663 
664 /* Add 'mask' into the mask list, if it is not already there. */
665 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
666                             const struct sw_flow_mask *new)
667 {
668         struct sw_flow_mask *mask;
669         mask = flow_mask_find(tbl, new);
670         if (!mask) {
671                 /* Allocate a new mask if none exsits. */
672                 mask = mask_alloc();
673                 if (!mask)
674                         return -ENOMEM;
675                 mask->key = new->key;
676                 mask->range = new->range;
677                 list_add_rcu(&mask->list, &tbl->mask_list);
678         } else {
679                 BUG_ON(!mask->ref_count);
680                 mask->ref_count++;
681         }
682 
683         flow->mask = mask;
684         return 0;
685 }
686 
687 /* Must be called with OVS mutex held. */
688 static void flow_key_insert(struct flow_table *table, struct sw_flow *flow)
689 {
690         struct table_instance *new_ti = NULL;
691         struct table_instance *ti;
692 
693         flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range);
694         ti = ovsl_dereference(table->ti);
695         table_instance_insert(ti, flow);
696         table->count++;
697 
698         /* Expand table, if necessary, to make room. */
699         if (table->count > ti->n_buckets)
700                 new_ti = table_instance_expand(ti, false);
701         else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL))
702                 new_ti = table_instance_rehash(ti, ti->n_buckets, false);
703 
704         if (new_ti) {
705                 rcu_assign_pointer(table->ti, new_ti);
706                 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
707                 table->last_rehash = jiffies;
708         }
709 }
710 
711 /* Must be called with OVS mutex held. */
712 static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow)
713 {
714         struct table_instance *ti;
715 
716         flow->ufid_table.hash = ufid_hash(&flow->id);
717         ti = ovsl_dereference(table->ufid_ti);
718         ufid_table_instance_insert(ti, flow);
719         table->ufid_count++;
720 
721         /* Expand table, if necessary, to make room. */
722         if (table->ufid_count > ti->n_buckets) {
723                 struct table_instance *new_ti;
724 
725                 new_ti = table_instance_expand(ti, true);
726                 if (new_ti) {
727                         rcu_assign_pointer(table->ufid_ti, new_ti);
728                         call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
729                 }
730         }
731 }
732 
733 /* Must be called with OVS mutex held. */
734 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
735                         const struct sw_flow_mask *mask)
736 {
737         int err;
738 
739         err = flow_mask_insert(table, flow, mask);
740         if (err)
741                 return err;
742         flow_key_insert(table, flow);
743         if (ovs_identifier_is_ufid(&flow->id))
744                 flow_ufid_insert(table, flow);
745 
746         return 0;
747 }
748 
749 /* Initializes the flow module.
750  * Returns zero if successful or a negative error code. */
751 int ovs_flow_init(void)
752 {
753         BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
754         BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));
755 
756         flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
757                                        + (nr_node_ids
758                                           * sizeof(struct flow_stats *)),
759                                        0, 0, NULL);
760         if (flow_cache == NULL)
761                 return -ENOMEM;
762 
763         flow_stats_cache
764                 = kmem_cache_create("sw_flow_stats", sizeof(struct flow_stats),
765                                     0, SLAB_HWCACHE_ALIGN, NULL);
766         if (flow_stats_cache == NULL) {
767                 kmem_cache_destroy(flow_cache);
768                 flow_cache = NULL;
769                 return -ENOMEM;
770         }
771 
772         return 0;
773 }
774 
775 /* Uninitializes the flow module. */
776 void ovs_flow_exit(void)
777 {
778         kmem_cache_destroy(flow_stats_cache);
779         kmem_cache_destroy(flow_cache);
780 }
781 

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