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