1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2007-2014 Nicira, Inc. 4 */ 5 6 #include "flow.h" 7 #include "datapath.h" 8 #include "flow_netlink.h" 9 #include <linux/uaccess.h> 10 #include <linux/netdevice.h> 11 #include <linux/etherdevice.h> 12 #include <linux/if_ether.h> 13 #include <linux/if_vlan.h> 14 #include <net/llc_pdu.h> 15 #include <linux/kernel.h> 16 #include <linux/jhash.h> 17 #include <linux/jiffies.h> 18 #include <linux/llc.h> 19 #include <linux/module.h> 20 #include <linux/in.h> 21 #include <linux/rcupdate.h> 22 #include <linux/cpumask.h> 23 #include <linux/if_arp.h> 24 #include <linux/ip.h> 25 #include <linux/ipv6.h> 26 #include <linux/sctp.h> 27 #include <linux/tcp.h> 28 #include <linux/udp.h> 29 #include <linux/icmp.h> 30 #include <linux/icmpv6.h> 31 #include <linux/rculist.h> 32 #include <net/ip.h> 33 #include <net/ipv6.h> 34 #include <net/ndisc.h> 35 36 #define TBL_MIN_BUCKETS 1024 37 #define REHASH_INTERVAL (10 * 60 * HZ) 38 39 static struct kmem_cache *flow_cache; 40 struct kmem_cache *flow_stats_cache __read_mostly; 41 42 static u16 range_n_bytes(const struct sw_flow_key_range *range) 43 { 44 return range->end - range->start; 45 } 46 47 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, 48 bool full, const struct sw_flow_mask *mask) 49 { 50 int start = full ? 0 : mask->range.start; 51 int len = full ? sizeof *dst : range_n_bytes(&mask->range); 52 const long *m = (const long *)((const u8 *)&mask->key + start); 53 const long *s = (const long *)((const u8 *)src + start); 54 long *d = (long *)((u8 *)dst + start); 55 int i; 56 57 /* If 'full' is true then all of 'dst' is fully initialized. Otherwise, 58 * if 'full' is false the memory outside of the 'mask->range' is left 59 * uninitialized. This can be used as an optimization when further 60 * operations on 'dst' only use contents within 'mask->range'. 61 */ 62 for (i = 0; i < len; i += sizeof(long)) 63 *d++ = *s++ & *m++; 64 } 65 66 struct sw_flow *ovs_flow_alloc(void) 67 { 68 struct sw_flow *flow; 69 struct sw_flow_stats *stats; 70 71 flow = kmem_cache_zalloc(flow_cache, GFP_KERNEL); 72 if (!flow) 73 return ERR_PTR(-ENOMEM); 74 75 flow->stats_last_writer = -1; 76 77 /* Initialize the default stat node. */ 78 stats = kmem_cache_alloc_node(flow_stats_cache, 79 GFP_KERNEL | __GFP_ZERO, 80 node_online(0) ? 0 : NUMA_NO_NODE); 81 if (!stats) 82 goto err; 83 84 spin_lock_init(&stats->lock); 85 86 RCU_INIT_POINTER(flow->stats[0], stats); 87 88 cpumask_set_cpu(0, &flow->cpu_used_mask); 89 90 return flow; 91 err: 92 kmem_cache_free(flow_cache, flow); 93 return ERR_PTR(-ENOMEM); 94 } 95 96 int ovs_flow_tbl_count(const struct flow_table *table) 97 { 98 return table->count; 99 } 100 101 static void flow_free(struct sw_flow *flow) 102 { 103 int cpu; 104 105 if (ovs_identifier_is_key(&flow->id)) 106 kfree(flow->id.unmasked_key); 107 if (flow->sf_acts) 108 ovs_nla_free_flow_actions((struct sw_flow_actions __force *)flow->sf_acts); 109 /* We open code this to make sure cpu 0 is always considered */ 110 for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) 111 if (flow->stats[cpu]) 112 kmem_cache_free(flow_stats_cache, 113 (struct sw_flow_stats __force *)flow->stats[cpu]); 114 kmem_cache_free(flow_cache, flow); 115 } 116 117 static void rcu_free_flow_callback(struct rcu_head *rcu) 118 { 119 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); 120 121 flow_free(flow); 122 } 123 124 void ovs_flow_free(struct sw_flow *flow, bool deferred) 125 { 126 if (!flow) 127 return; 128 129 if (deferred) 130 call_rcu(&flow->rcu, rcu_free_flow_callback); 131 else 132 flow_free(flow); 133 } 134 135 static void __table_instance_destroy(struct table_instance *ti) 136 { 137 kvfree(ti->buckets); 138 kfree(ti); 139 } 140 141 static struct table_instance *table_instance_alloc(int new_size) 142 { 143 struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL); 144 int i; 145 146 if (!ti) 147 return NULL; 148 149 ti->buckets = kvmalloc_array(new_size, sizeof(struct hlist_head), 150 GFP_KERNEL); 151 if (!ti->buckets) { 152 kfree(ti); 153 return NULL; 154 } 155 156 for (i = 0; i < new_size; i++) 157 INIT_HLIST_HEAD(&ti->buckets[i]); 158 159 ti->n_buckets = new_size; 160 ti->node_ver = 0; 161 ti->keep_flows = false; 162 get_random_bytes(&ti->hash_seed, sizeof(u32)); 163 164 return ti; 165 } 166 167 int ovs_flow_tbl_init(struct flow_table *table) 168 { 169 struct table_instance *ti, *ufid_ti; 170 171 ti = table_instance_alloc(TBL_MIN_BUCKETS); 172 173 if (!ti) 174 return -ENOMEM; 175 176 ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); 177 if (!ufid_ti) 178 goto free_ti; 179 180 rcu_assign_pointer(table->ti, ti); 181 rcu_assign_pointer(table->ufid_ti, ufid_ti); 182 INIT_LIST_HEAD(&table->mask_list); 183 table->last_rehash = jiffies; 184 table->count = 0; 185 table->ufid_count = 0; 186 return 0; 187 188 free_ti: 189 __table_instance_destroy(ti); 190 return -ENOMEM; 191 } 192 193 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu) 194 { 195 struct table_instance *ti = container_of(rcu, struct table_instance, rcu); 196 197 __table_instance_destroy(ti); 198 } 199 200 static void table_instance_destroy(struct table_instance *ti, 201 struct table_instance *ufid_ti, 202 bool deferred) 203 { 204 int i; 205 206 if (!ti) 207 return; 208 209 BUG_ON(!ufid_ti); 210 if (ti->keep_flows) 211 goto skip_flows; 212 213 for (i = 0; i < ti->n_buckets; i++) { 214 struct sw_flow *flow; 215 struct hlist_head *head = &ti->buckets[i]; 216 struct hlist_node *n; 217 int ver = ti->node_ver; 218 int ufid_ver = ufid_ti->node_ver; 219 220 hlist_for_each_entry_safe(flow, n, head, flow_table.node[ver]) { 221 hlist_del_rcu(&flow->flow_table.node[ver]); 222 if (ovs_identifier_is_ufid(&flow->id)) 223 hlist_del_rcu(&flow->ufid_table.node[ufid_ver]); 224 ovs_flow_free(flow, deferred); 225 } 226 } 227 228 skip_flows: 229 if (deferred) { 230 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 231 call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb); 232 } else { 233 __table_instance_destroy(ti); 234 __table_instance_destroy(ufid_ti); 235 } 236 } 237 238 /* No need for locking this function is called from RCU callback or 239 * error path. 240 */ 241 void ovs_flow_tbl_destroy(struct flow_table *table) 242 { 243 struct table_instance *ti = rcu_dereference_raw(table->ti); 244 struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti); 245 246 table_instance_destroy(ti, ufid_ti, false); 247 } 248 249 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, 250 u32 *bucket, u32 *last) 251 { 252 struct sw_flow *flow; 253 struct hlist_head *head; 254 int ver; 255 int i; 256 257 ver = ti->node_ver; 258 while (*bucket < ti->n_buckets) { 259 i = 0; 260 head = &ti->buckets[*bucket]; 261 hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) { 262 if (i < *last) { 263 i++; 264 continue; 265 } 266 *last = i + 1; 267 return flow; 268 } 269 (*bucket)++; 270 *last = 0; 271 } 272 273 return NULL; 274 } 275 276 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash) 277 { 278 hash = jhash_1word(hash, ti->hash_seed); 279 return &ti->buckets[hash & (ti->n_buckets - 1)]; 280 } 281 282 static void table_instance_insert(struct table_instance *ti, 283 struct sw_flow *flow) 284 { 285 struct hlist_head *head; 286 287 head = find_bucket(ti, flow->flow_table.hash); 288 hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head); 289 } 290 291 static void ufid_table_instance_insert(struct table_instance *ti, 292 struct sw_flow *flow) 293 { 294 struct hlist_head *head; 295 296 head = find_bucket(ti, flow->ufid_table.hash); 297 hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head); 298 } 299 300 static void flow_table_copy_flows(struct table_instance *old, 301 struct table_instance *new, bool ufid) 302 { 303 int old_ver; 304 int i; 305 306 old_ver = old->node_ver; 307 new->node_ver = !old_ver; 308 309 /* Insert in new table. */ 310 for (i = 0; i < old->n_buckets; i++) { 311 struct sw_flow *flow; 312 struct hlist_head *head = &old->buckets[i]; 313 314 if (ufid) 315 hlist_for_each_entry(flow, head, 316 ufid_table.node[old_ver]) 317 ufid_table_instance_insert(new, flow); 318 else 319 hlist_for_each_entry(flow, head, 320 flow_table.node[old_ver]) 321 table_instance_insert(new, flow); 322 } 323 324 old->keep_flows = true; 325 } 326 327 static struct table_instance *table_instance_rehash(struct table_instance *ti, 328 int n_buckets, bool ufid) 329 { 330 struct table_instance *new_ti; 331 332 new_ti = table_instance_alloc(n_buckets); 333 if (!new_ti) 334 return NULL; 335 336 flow_table_copy_flows(ti, new_ti, ufid); 337 338 return new_ti; 339 } 340 341 int ovs_flow_tbl_flush(struct flow_table *flow_table) 342 { 343 struct table_instance *old_ti, *new_ti; 344 struct table_instance *old_ufid_ti, *new_ufid_ti; 345 346 new_ti = table_instance_alloc(TBL_MIN_BUCKETS); 347 if (!new_ti) 348 return -ENOMEM; 349 new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); 350 if (!new_ufid_ti) 351 goto err_free_ti; 352 353 old_ti = ovsl_dereference(flow_table->ti); 354 old_ufid_ti = ovsl_dereference(flow_table->ufid_ti); 355 356 rcu_assign_pointer(flow_table->ti, new_ti); 357 rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti); 358 flow_table->last_rehash = jiffies; 359 flow_table->count = 0; 360 flow_table->ufid_count = 0; 361 362 table_instance_destroy(old_ti, old_ufid_ti, true); 363 return 0; 364 365 err_free_ti: 366 __table_instance_destroy(new_ti); 367 return -ENOMEM; 368 } 369 370 static u32 flow_hash(const struct sw_flow_key *key, 371 const struct sw_flow_key_range *range) 372 { 373 int key_start = range->start; 374 int key_end = range->end; 375 const u32 *hash_key = (const u32 *)((const u8 *)key + key_start); 376 int hash_u32s = (key_end - key_start) >> 2; 377 378 /* Make sure number of hash bytes are multiple of u32. */ 379 BUILD_BUG_ON(sizeof(long) % sizeof(u32)); 380 381 return jhash2(hash_key, hash_u32s, 0); 382 } 383 384 static int flow_key_start(const struct sw_flow_key *key) 385 { 386 if (key->tun_proto) 387 return 0; 388 else 389 return rounddown(offsetof(struct sw_flow_key, phy), 390 sizeof(long)); 391 } 392 393 static bool cmp_key(const struct sw_flow_key *key1, 394 const struct sw_flow_key *key2, 395 int key_start, int key_end) 396 { 397 const long *cp1 = (const long *)((const u8 *)key1 + key_start); 398 const long *cp2 = (const long *)((const u8 *)key2 + key_start); 399 long diffs = 0; 400 int i; 401 402 for (i = key_start; i < key_end; i += sizeof(long)) 403 diffs |= *cp1++ ^ *cp2++; 404 405 return diffs == 0; 406 } 407 408 static bool flow_cmp_masked_key(const struct sw_flow *flow, 409 const struct sw_flow_key *key, 410 const struct sw_flow_key_range *range) 411 { 412 return cmp_key(&flow->key, key, range->start, range->end); 413 } 414 415 static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow, 416 const struct sw_flow_match *match) 417 { 418 struct sw_flow_key *key = match->key; 419 int key_start = flow_key_start(key); 420 int key_end = match->range.end; 421 422 BUG_ON(ovs_identifier_is_ufid(&flow->id)); 423 return cmp_key(flow->id.unmasked_key, key, key_start, key_end); 424 } 425 426 static struct sw_flow *masked_flow_lookup(struct table_instance *ti, 427 const struct sw_flow_key *unmasked, 428 const struct sw_flow_mask *mask) 429 { 430 struct sw_flow *flow; 431 struct hlist_head *head; 432 u32 hash; 433 struct sw_flow_key masked_key; 434 435 ovs_flow_mask_key(&masked_key, unmasked, false, mask); 436 hash = flow_hash(&masked_key, &mask->range); 437 head = find_bucket(ti, hash); 438 hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver]) { 439 if (flow->mask == mask && flow->flow_table.hash == hash && 440 flow_cmp_masked_key(flow, &masked_key, &mask->range)) 441 return flow; 442 } 443 return NULL; 444 } 445 446 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl, 447 const struct sw_flow_key *key, 448 u32 *n_mask_hit) 449 { 450 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); 451 struct sw_flow_mask *mask; 452 struct sw_flow *flow; 453 454 *n_mask_hit = 0; 455 list_for_each_entry_rcu(mask, &tbl->mask_list, list) { 456 (*n_mask_hit)++; 457 flow = masked_flow_lookup(ti, key, mask); 458 if (flow) /* Found */ 459 return flow; 460 } 461 return NULL; 462 } 463 464 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl, 465 const struct sw_flow_key *key) 466 { 467 u32 __always_unused n_mask_hit; 468 469 return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit); 470 } 471 472 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl, 473 const struct sw_flow_match *match) 474 { 475 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); 476 struct sw_flow_mask *mask; 477 struct sw_flow *flow; 478 479 /* Always called under ovs-mutex. */ 480 list_for_each_entry(mask, &tbl->mask_list, list) { 481 flow = masked_flow_lookup(ti, match->key, mask); 482 if (flow && ovs_identifier_is_key(&flow->id) && 483 ovs_flow_cmp_unmasked_key(flow, match)) 484 return flow; 485 } 486 return NULL; 487 } 488 489 static u32 ufid_hash(const struct sw_flow_id *sfid) 490 { 491 return jhash(sfid->ufid, sfid->ufid_len, 0); 492 } 493 494 static bool ovs_flow_cmp_ufid(const struct sw_flow *flow, 495 const struct sw_flow_id *sfid) 496 { 497 if (flow->id.ufid_len != sfid->ufid_len) 498 return false; 499 500 return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len); 501 } 502 503 bool ovs_flow_cmp(const struct sw_flow *flow, const struct sw_flow_match *match) 504 { 505 if (ovs_identifier_is_ufid(&flow->id)) 506 return flow_cmp_masked_key(flow, match->key, &match->range); 507 508 return ovs_flow_cmp_unmasked_key(flow, match); 509 } 510 511 struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl, 512 const struct sw_flow_id *ufid) 513 { 514 struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti); 515 struct sw_flow *flow; 516 struct hlist_head *head; 517 u32 hash; 518 519 hash = ufid_hash(ufid); 520 head = find_bucket(ti, hash); 521 hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver]) { 522 if (flow->ufid_table.hash == hash && 523 ovs_flow_cmp_ufid(flow, ufid)) 524 return flow; 525 } 526 return NULL; 527 } 528 529 int ovs_flow_tbl_num_masks(const struct flow_table *table) 530 { 531 struct sw_flow_mask *mask; 532 int num = 0; 533 534 list_for_each_entry(mask, &table->mask_list, list) 535 num++; 536 537 return num; 538 } 539 540 static struct table_instance *table_instance_expand(struct table_instance *ti, 541 bool ufid) 542 { 543 return table_instance_rehash(ti, ti->n_buckets * 2, ufid); 544 } 545 546 /* Remove 'mask' from the mask list, if it is not needed any more. */ 547 static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask) 548 { 549 if (mask) { 550 /* ovs-lock is required to protect mask-refcount and 551 * mask list. 552 */ 553 ASSERT_OVSL(); 554 BUG_ON(!mask->ref_count); 555 mask->ref_count--; 556 557 if (!mask->ref_count) { 558 list_del_rcu(&mask->list); 559 kfree_rcu(mask, rcu); 560 } 561 } 562 } 563 564 /* Must be called with OVS mutex held. */ 565 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow) 566 { 567 struct table_instance *ti = ovsl_dereference(table->ti); 568 struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti); 569 570 BUG_ON(table->count == 0); 571 hlist_del_rcu(&flow->flow_table.node[ti->node_ver]); 572 table->count--; 573 if (ovs_identifier_is_ufid(&flow->id)) { 574 hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]); 575 table->ufid_count--; 576 } 577 578 /* RCU delete the mask. 'flow->mask' is not NULLed, as it should be 579 * accessible as long as the RCU read lock is held. 580 */ 581 flow_mask_remove(table, flow->mask); 582 } 583 584 static struct sw_flow_mask *mask_alloc(void) 585 { 586 struct sw_flow_mask *mask; 587 588 mask = kmalloc(sizeof(*mask), GFP_KERNEL); 589 if (mask) 590 mask->ref_count = 1; 591 592 return mask; 593 } 594 595 static bool mask_equal(const struct sw_flow_mask *a, 596 const struct sw_flow_mask *b) 597 { 598 const u8 *a_ = (const u8 *)&a->key + a->range.start; 599 const u8 *b_ = (const u8 *)&b->key + b->range.start; 600 601 return (a->range.end == b->range.end) 602 && (a->range.start == b->range.start) 603 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0); 604 } 605 606 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl, 607 const struct sw_flow_mask *mask) 608 { 609 struct list_head *ml; 610 611 list_for_each(ml, &tbl->mask_list) { 612 struct sw_flow_mask *m; 613 m = container_of(ml, struct sw_flow_mask, list); 614 if (mask_equal(mask, m)) 615 return m; 616 } 617 618 return NULL; 619 } 620 621 /* Add 'mask' into the mask list, if it is not already there. */ 622 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow, 623 const struct sw_flow_mask *new) 624 { 625 struct sw_flow_mask *mask; 626 mask = flow_mask_find(tbl, new); 627 if (!mask) { 628 /* Allocate a new mask if none exsits. */ 629 mask = mask_alloc(); 630 if (!mask) 631 return -ENOMEM; 632 mask->key = new->key; 633 mask->range = new->range; 634 list_add_rcu(&mask->list, &tbl->mask_list); 635 } else { 636 BUG_ON(!mask->ref_count); 637 mask->ref_count++; 638 } 639 640 flow->mask = mask; 641 return 0; 642 } 643 644 /* Must be called with OVS mutex held. */ 645 static void flow_key_insert(struct flow_table *table, struct sw_flow *flow) 646 { 647 struct table_instance *new_ti = NULL; 648 struct table_instance *ti; 649 650 flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range); 651 ti = ovsl_dereference(table->ti); 652 table_instance_insert(ti, flow); 653 table->count++; 654 655 /* Expand table, if necessary, to make room. */ 656 if (table->count > ti->n_buckets) 657 new_ti = table_instance_expand(ti, false); 658 else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL)) 659 new_ti = table_instance_rehash(ti, ti->n_buckets, false); 660 661 if (new_ti) { 662 rcu_assign_pointer(table->ti, new_ti); 663 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 664 table->last_rehash = jiffies; 665 } 666 } 667 668 /* Must be called with OVS mutex held. */ 669 static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow) 670 { 671 struct table_instance *ti; 672 673 flow->ufid_table.hash = ufid_hash(&flow->id); 674 ti = ovsl_dereference(table->ufid_ti); 675 ufid_table_instance_insert(ti, flow); 676 table->ufid_count++; 677 678 /* Expand table, if necessary, to make room. */ 679 if (table->ufid_count > ti->n_buckets) { 680 struct table_instance *new_ti; 681 682 new_ti = table_instance_expand(ti, true); 683 if (new_ti) { 684 rcu_assign_pointer(table->ufid_ti, new_ti); 685 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 686 } 687 } 688 } 689 690 /* Must be called with OVS mutex held. */ 691 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow, 692 const struct sw_flow_mask *mask) 693 { 694 int err; 695 696 err = flow_mask_insert(table, flow, mask); 697 if (err) 698 return err; 699 flow_key_insert(table, flow); 700 if (ovs_identifier_is_ufid(&flow->id)) 701 flow_ufid_insert(table, flow); 702 703 return 0; 704 } 705 706 /* Initializes the flow module. 707 * Returns zero if successful or a negative error code. */ 708 int ovs_flow_init(void) 709 { 710 BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long)); 711 BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long)); 712 713 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow) 714 + (nr_cpu_ids 715 * sizeof(struct sw_flow_stats *)), 716 0, 0, NULL); 717 if (flow_cache == NULL) 718 return -ENOMEM; 719 720 flow_stats_cache 721 = kmem_cache_create("sw_flow_stats", sizeof(struct sw_flow_stats), 722 0, SLAB_HWCACHE_ALIGN, NULL); 723 if (flow_stats_cache == NULL) { 724 kmem_cache_destroy(flow_cache); 725 flow_cache = NULL; 726 return -ENOMEM; 727 } 728 729 return 0; 730 } 731 732 /* Uninitializes the flow module. */ 733 void ovs_flow_exit(void) 734 { 735 kmem_cache_destroy(flow_stats_cache); 736 kmem_cache_destroy(flow_cache); 737 } 738