1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Slab allocator functions that are independent of the allocator strategy 4 * 5 * (C) 2012 Christoph Lameter <cl@linux.com> 6 */ 7 #include <linux/slab.h> 8 9 #include <linux/mm.h> 10 #include <linux/poison.h> 11 #include <linux/interrupt.h> 12 #include <linux/memory.h> 13 #include <linux/cache.h> 14 #include <linux/compiler.h> 15 #include <linux/module.h> 16 #include <linux/cpu.h> 17 #include <linux/uaccess.h> 18 #include <linux/seq_file.h> 19 #include <linux/proc_fs.h> 20 #include <asm/cacheflush.h> 21 #include <asm/tlbflush.h> 22 #include <asm/page.h> 23 #include <linux/memcontrol.h> 24 25 #define CREATE_TRACE_POINTS 26 #include <trace/events/kmem.h> 27 28 #include "slab.h" 29 30 enum slab_state slab_state; 31 LIST_HEAD(slab_caches); 32 DEFINE_MUTEX(slab_mutex); 33 struct kmem_cache *kmem_cache; 34 35 #ifdef CONFIG_HARDENED_USERCOPY 36 bool usercopy_fallback __ro_after_init = 37 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK); 38 module_param(usercopy_fallback, bool, 0400); 39 MODULE_PARM_DESC(usercopy_fallback, 40 "WARN instead of reject usercopy whitelist violations"); 41 #endif 42 43 static LIST_HEAD(slab_caches_to_rcu_destroy); 44 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); 45 static DECLARE_WORK(slab_caches_to_rcu_destroy_work, 46 slab_caches_to_rcu_destroy_workfn); 47 48 /* 49 * Set of flags that will prevent slab merging 50 */ 51 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 52 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ 53 SLAB_FAILSLAB | SLAB_KASAN) 54 55 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ 56 SLAB_ACCOUNT) 57 58 /* 59 * Merge control. If this is set then no merging of slab caches will occur. 60 */ 61 static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); 62 63 static int __init setup_slab_nomerge(char *str) 64 { 65 slab_nomerge = true; 66 return 1; 67 } 68 69 #ifdef CONFIG_SLUB 70 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); 71 #endif 72 73 __setup("slab_nomerge", setup_slab_nomerge); 74 75 /* 76 * Determine the size of a slab object 77 */ 78 unsigned int kmem_cache_size(struct kmem_cache *s) 79 { 80 return s->object_size; 81 } 82 EXPORT_SYMBOL(kmem_cache_size); 83 84 #ifdef CONFIG_DEBUG_VM 85 static int kmem_cache_sanity_check(const char *name, unsigned int size) 86 { 87 if (!name || in_interrupt() || size < sizeof(void *) || 88 size > KMALLOC_MAX_SIZE) { 89 pr_err("kmem_cache_create(%s) integrity check failed\n", name); 90 return -EINVAL; 91 } 92 93 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 94 return 0; 95 } 96 #else 97 static inline int kmem_cache_sanity_check(const char *name, unsigned int size) 98 { 99 return 0; 100 } 101 #endif 102 103 void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p) 104 { 105 size_t i; 106 107 for (i = 0; i < nr; i++) { 108 if (s) 109 kmem_cache_free(s, p[i]); 110 else 111 kfree(p[i]); 112 } 113 } 114 115 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, 116 void **p) 117 { 118 size_t i; 119 120 for (i = 0; i < nr; i++) { 121 void *x = p[i] = kmem_cache_alloc(s, flags); 122 if (!x) { 123 __kmem_cache_free_bulk(s, i, p); 124 return 0; 125 } 126 } 127 return i; 128 } 129 130 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB) 131 132 LIST_HEAD(slab_root_caches); 133 134 void slab_init_memcg_params(struct kmem_cache *s) 135 { 136 s->memcg_params.root_cache = NULL; 137 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL); 138 INIT_LIST_HEAD(&s->memcg_params.children); 139 } 140 141 static int init_memcg_params(struct kmem_cache *s, 142 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 143 { 144 struct memcg_cache_array *arr; 145 146 if (root_cache) { 147 s->memcg_params.root_cache = root_cache; 148 s->memcg_params.memcg = memcg; 149 INIT_LIST_HEAD(&s->memcg_params.children_node); 150 INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node); 151 return 0; 152 } 153 154 slab_init_memcg_params(s); 155 156 if (!memcg_nr_cache_ids) 157 return 0; 158 159 arr = kvzalloc(sizeof(struct memcg_cache_array) + 160 memcg_nr_cache_ids * sizeof(void *), 161 GFP_KERNEL); 162 if (!arr) 163 return -ENOMEM; 164 165 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr); 166 return 0; 167 } 168 169 static void destroy_memcg_params(struct kmem_cache *s) 170 { 171 if (is_root_cache(s)) 172 kvfree(rcu_access_pointer(s->memcg_params.memcg_caches)); 173 } 174 175 static void free_memcg_params(struct rcu_head *rcu) 176 { 177 struct memcg_cache_array *old; 178 179 old = container_of(rcu, struct memcg_cache_array, rcu); 180 kvfree(old); 181 } 182 183 static int update_memcg_params(struct kmem_cache *s, int new_array_size) 184 { 185 struct memcg_cache_array *old, *new; 186 187 new = kvzalloc(sizeof(struct memcg_cache_array) + 188 new_array_size * sizeof(void *), GFP_KERNEL); 189 if (!new) 190 return -ENOMEM; 191 192 old = rcu_dereference_protected(s->memcg_params.memcg_caches, 193 lockdep_is_held(&slab_mutex)); 194 if (old) 195 memcpy(new->entries, old->entries, 196 memcg_nr_cache_ids * sizeof(void *)); 197 198 rcu_assign_pointer(s->memcg_params.memcg_caches, new); 199 if (old) 200 call_rcu(&old->rcu, free_memcg_params); 201 return 0; 202 } 203 204 int memcg_update_all_caches(int num_memcgs) 205 { 206 struct kmem_cache *s; 207 int ret = 0; 208 209 mutex_lock(&slab_mutex); 210 list_for_each_entry(s, &slab_root_caches, root_caches_node) { 211 ret = update_memcg_params(s, num_memcgs); 212 /* 213 * Instead of freeing the memory, we'll just leave the caches 214 * up to this point in an updated state. 215 */ 216 if (ret) 217 break; 218 } 219 mutex_unlock(&slab_mutex); 220 return ret; 221 } 222 223 void memcg_link_cache(struct kmem_cache *s) 224 { 225 if (is_root_cache(s)) { 226 list_add(&s->root_caches_node, &slab_root_caches); 227 } else { 228 list_add(&s->memcg_params.children_node, 229 &s->memcg_params.root_cache->memcg_params.children); 230 list_add(&s->memcg_params.kmem_caches_node, 231 &s->memcg_params.memcg->kmem_caches); 232 } 233 } 234 235 static void memcg_unlink_cache(struct kmem_cache *s) 236 { 237 if (is_root_cache(s)) { 238 list_del(&s->root_caches_node); 239 } else { 240 list_del(&s->memcg_params.children_node); 241 list_del(&s->memcg_params.kmem_caches_node); 242 } 243 } 244 #else 245 static inline int init_memcg_params(struct kmem_cache *s, 246 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 247 { 248 return 0; 249 } 250 251 static inline void destroy_memcg_params(struct kmem_cache *s) 252 { 253 } 254 255 static inline void memcg_unlink_cache(struct kmem_cache *s) 256 { 257 } 258 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */ 259 260 /* 261 * Figure out what the alignment of the objects will be given a set of 262 * flags, a user specified alignment and the size of the objects. 263 */ 264 static unsigned int calculate_alignment(slab_flags_t flags, 265 unsigned int align, unsigned int size) 266 { 267 /* 268 * If the user wants hardware cache aligned objects then follow that 269 * suggestion if the object is sufficiently large. 270 * 271 * The hardware cache alignment cannot override the specified 272 * alignment though. If that is greater then use it. 273 */ 274 if (flags & SLAB_HWCACHE_ALIGN) { 275 unsigned int ralign; 276 277 ralign = cache_line_size(); 278 while (size <= ralign / 2) 279 ralign /= 2; 280 align = max(align, ralign); 281 } 282 283 if (align < ARCH_SLAB_MINALIGN) 284 align = ARCH_SLAB_MINALIGN; 285 286 return ALIGN(align, sizeof(void *)); 287 } 288 289 /* 290 * Find a mergeable slab cache 291 */ 292 int slab_unmergeable(struct kmem_cache *s) 293 { 294 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 295 return 1; 296 297 if (!is_root_cache(s)) 298 return 1; 299 300 if (s->ctor) 301 return 1; 302 303 if (s->usersize) 304 return 1; 305 306 /* 307 * We may have set a slab to be unmergeable during bootstrap. 308 */ 309 if (s->refcount < 0) 310 return 1; 311 312 return 0; 313 } 314 315 struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, 316 slab_flags_t flags, const char *name, void (*ctor)(void *)) 317 { 318 struct kmem_cache *s; 319 320 if (slab_nomerge) 321 return NULL; 322 323 if (ctor) 324 return NULL; 325 326 size = ALIGN(size, sizeof(void *)); 327 align = calculate_alignment(flags, align, size); 328 size = ALIGN(size, align); 329 flags = kmem_cache_flags(size, flags, name, NULL); 330 331 if (flags & SLAB_NEVER_MERGE) 332 return NULL; 333 334 list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) { 335 if (slab_unmergeable(s)) 336 continue; 337 338 if (size > s->size) 339 continue; 340 341 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 342 continue; 343 /* 344 * Check if alignment is compatible. 345 * Courtesy of Adrian Drzewiecki 346 */ 347 if ((s->size & ~(align - 1)) != s->size) 348 continue; 349 350 if (s->size - size >= sizeof(void *)) 351 continue; 352 353 if (IS_ENABLED(CONFIG_SLAB) && align && 354 (align > s->align || s->align % align)) 355 continue; 356 357 return s; 358 } 359 return NULL; 360 } 361 362 static struct kmem_cache *create_cache(const char *name, 363 unsigned int object_size, unsigned int align, 364 slab_flags_t flags, unsigned int useroffset, 365 unsigned int usersize, void (*ctor)(void *), 366 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 367 { 368 struct kmem_cache *s; 369 int err; 370 371 if (WARN_ON(useroffset + usersize > object_size)) 372 useroffset = usersize = 0; 373 374 err = -ENOMEM; 375 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 376 if (!s) 377 goto out; 378 379 s->name = name; 380 s->size = s->object_size = object_size; 381 s->align = align; 382 s->ctor = ctor; 383 s->useroffset = useroffset; 384 s->usersize = usersize; 385 386 err = init_memcg_params(s, memcg, root_cache); 387 if (err) 388 goto out_free_cache; 389 390 err = __kmem_cache_create(s, flags); 391 if (err) 392 goto out_free_cache; 393 394 s->refcount = 1; 395 list_add(&s->list, &slab_caches); 396 memcg_link_cache(s); 397 out: 398 if (err) 399 return ERR_PTR(err); 400 return s; 401 402 out_free_cache: 403 destroy_memcg_params(s); 404 kmem_cache_free(kmem_cache, s); 405 goto out; 406 } 407 408 /* 409 * kmem_cache_create_usercopy - Create a cache. 410 * @name: A string which is used in /proc/slabinfo to identify this cache. 411 * @size: The size of objects to be created in this cache. 412 * @align: The required alignment for the objects. 413 * @flags: SLAB flags 414 * @useroffset: Usercopy region offset 415 * @usersize: Usercopy region size 416 * @ctor: A constructor for the objects. 417 * 418 * Returns a ptr to the cache on success, NULL on failure. 419 * Cannot be called within a interrupt, but can be interrupted. 420 * The @ctor is run when new pages are allocated by the cache. 421 * 422 * The flags are 423 * 424 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 425 * to catch references to uninitialised memory. 426 * 427 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 428 * for buffer overruns. 429 * 430 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 431 * cacheline. This can be beneficial if you're counting cycles as closely 432 * as davem. 433 */ 434 struct kmem_cache * 435 kmem_cache_create_usercopy(const char *name, 436 unsigned int size, unsigned int align, 437 slab_flags_t flags, 438 unsigned int useroffset, unsigned int usersize, 439 void (*ctor)(void *)) 440 { 441 struct kmem_cache *s = NULL; 442 const char *cache_name; 443 int err; 444 445 get_online_cpus(); 446 get_online_mems(); 447 memcg_get_cache_ids(); 448 449 mutex_lock(&slab_mutex); 450 451 err = kmem_cache_sanity_check(name, size); 452 if (err) { 453 goto out_unlock; 454 } 455 456 /* Refuse requests with allocator specific flags */ 457 if (flags & ~SLAB_FLAGS_PERMITTED) { 458 err = -EINVAL; 459 goto out_unlock; 460 } 461 462 /* 463 * Some allocators will constraint the set of valid flags to a subset 464 * of all flags. We expect them to define CACHE_CREATE_MASK in this 465 * case, and we'll just provide them with a sanitized version of the 466 * passed flags. 467 */ 468 flags &= CACHE_CREATE_MASK; 469 470 /* Fail closed on bad usersize of useroffset values. */ 471 if (WARN_ON(!usersize && useroffset) || 472 WARN_ON(size < usersize || size - usersize < useroffset)) 473 usersize = useroffset = 0; 474 475 if (!usersize) 476 s = __kmem_cache_alias(name, size, align, flags, ctor); 477 if (s) 478 goto out_unlock; 479 480 cache_name = kstrdup_const(name, GFP_KERNEL); 481 if (!cache_name) { 482 err = -ENOMEM; 483 goto out_unlock; 484 } 485 486 s = create_cache(cache_name, size, 487 calculate_alignment(flags, align, size), 488 flags, useroffset, usersize, ctor, NULL, NULL); 489 if (IS_ERR(s)) { 490 err = PTR_ERR(s); 491 kfree_const(cache_name); 492 } 493 494 out_unlock: 495 mutex_unlock(&slab_mutex); 496 497 memcg_put_cache_ids(); 498 put_online_mems(); 499 put_online_cpus(); 500 501 if (err) { 502 if (flags & SLAB_PANIC) 503 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", 504 name, err); 505 else { 506 pr_warn("kmem_cache_create(%s) failed with error %d\n", 507 name, err); 508 dump_stack(); 509 } 510 return NULL; 511 } 512 return s; 513 } 514 EXPORT_SYMBOL(kmem_cache_create_usercopy); 515 516 struct kmem_cache * 517 kmem_cache_create(const char *name, unsigned int size, unsigned int align, 518 slab_flags_t flags, void (*ctor)(void *)) 519 { 520 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0, 521 ctor); 522 } 523 EXPORT_SYMBOL(kmem_cache_create); 524 525 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) 526 { 527 LIST_HEAD(to_destroy); 528 struct kmem_cache *s, *s2; 529 530 /* 531 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the 532 * @slab_caches_to_rcu_destroy list. The slab pages are freed 533 * through RCU and and the associated kmem_cache are dereferenced 534 * while freeing the pages, so the kmem_caches should be freed only 535 * after the pending RCU operations are finished. As rcu_barrier() 536 * is a pretty slow operation, we batch all pending destructions 537 * asynchronously. 538 */ 539 mutex_lock(&slab_mutex); 540 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); 541 mutex_unlock(&slab_mutex); 542 543 if (list_empty(&to_destroy)) 544 return; 545 546 rcu_barrier(); 547 548 list_for_each_entry_safe(s, s2, &to_destroy, list) { 549 #ifdef SLAB_SUPPORTS_SYSFS 550 sysfs_slab_release(s); 551 #else 552 slab_kmem_cache_release(s); 553 #endif 554 } 555 } 556 557 static int shutdown_cache(struct kmem_cache *s) 558 { 559 /* free asan quarantined objects */ 560 kasan_cache_shutdown(s); 561 562 if (__kmem_cache_shutdown(s) != 0) 563 return -EBUSY; 564 565 memcg_unlink_cache(s); 566 list_del(&s->list); 567 568 if (s->flags & SLAB_TYPESAFE_BY_RCU) { 569 list_add_tail(&s->list, &slab_caches_to_rcu_destroy); 570 schedule_work(&slab_caches_to_rcu_destroy_work); 571 } else { 572 #ifdef SLAB_SUPPORTS_SYSFS 573 sysfs_slab_release(s); 574 #else 575 slab_kmem_cache_release(s); 576 #endif 577 } 578 579 return 0; 580 } 581 582 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB) 583 /* 584 * memcg_create_kmem_cache - Create a cache for a memory cgroup. 585 * @memcg: The memory cgroup the new cache is for. 586 * @root_cache: The parent of the new cache. 587 * 588 * This function attempts to create a kmem cache that will serve allocation 589 * requests going from @memcg to @root_cache. The new cache inherits properties 590 * from its parent. 591 */ 592 void memcg_create_kmem_cache(struct mem_cgroup *memcg, 593 struct kmem_cache *root_cache) 594 { 595 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ 596 struct cgroup_subsys_state *css = &memcg->css; 597 struct memcg_cache_array *arr; 598 struct kmem_cache *s = NULL; 599 char *cache_name; 600 int idx; 601 602 get_online_cpus(); 603 get_online_mems(); 604 605 mutex_lock(&slab_mutex); 606 607 /* 608 * The memory cgroup could have been offlined while the cache 609 * creation work was pending. 610 */ 611 if (memcg->kmem_state != KMEM_ONLINE) 612 goto out_unlock; 613 614 idx = memcg_cache_id(memcg); 615 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches, 616 lockdep_is_held(&slab_mutex)); 617 618 /* 619 * Since per-memcg caches are created asynchronously on first 620 * allocation (see memcg_kmem_get_cache()), several threads can try to 621 * create the same cache, but only one of them may succeed. 622 */ 623 if (arr->entries[idx]) 624 goto out_unlock; 625 626 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf)); 627 cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name, 628 css->serial_nr, memcg_name_buf); 629 if (!cache_name) 630 goto out_unlock; 631 632 s = create_cache(cache_name, root_cache->object_size, 633 root_cache->align, 634 root_cache->flags & CACHE_CREATE_MASK, 635 root_cache->useroffset, root_cache->usersize, 636 root_cache->ctor, memcg, root_cache); 637 /* 638 * If we could not create a memcg cache, do not complain, because 639 * that's not critical at all as we can always proceed with the root 640 * cache. 641 */ 642 if (IS_ERR(s)) { 643 kfree(cache_name); 644 goto out_unlock; 645 } 646 647 /* 648 * Since readers won't lock (see cache_from_memcg_idx()), we need a 649 * barrier here to ensure nobody will see the kmem_cache partially 650 * initialized. 651 */ 652 smp_wmb(); 653 arr->entries[idx] = s; 654 655 out_unlock: 656 mutex_unlock(&slab_mutex); 657 658 put_online_mems(); 659 put_online_cpus(); 660 } 661 662 static void kmemcg_deactivate_workfn(struct work_struct *work) 663 { 664 struct kmem_cache *s = container_of(work, struct kmem_cache, 665 memcg_params.deact_work); 666 667 get_online_cpus(); 668 get_online_mems(); 669 670 mutex_lock(&slab_mutex); 671 672 s->memcg_params.deact_fn(s); 673 674 mutex_unlock(&slab_mutex); 675 676 put_online_mems(); 677 put_online_cpus(); 678 679 /* done, put the ref from slab_deactivate_memcg_cache_rcu_sched() */ 680 css_put(&s->memcg_params.memcg->css); 681 } 682 683 static void kmemcg_deactivate_rcufn(struct rcu_head *head) 684 { 685 struct kmem_cache *s = container_of(head, struct kmem_cache, 686 memcg_params.deact_rcu_head); 687 688 /* 689 * We need to grab blocking locks. Bounce to ->deact_work. The 690 * work item shares the space with the RCU head and can't be 691 * initialized eariler. 692 */ 693 INIT_WORK(&s->memcg_params.deact_work, kmemcg_deactivate_workfn); 694 queue_work(memcg_kmem_cache_wq, &s->memcg_params.deact_work); 695 } 696 697 /** 698 * slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a 699 * sched RCU grace period 700 * @s: target kmem_cache 701 * @deact_fn: deactivation function to call 702 * 703 * Schedule @deact_fn to be invoked with online cpus, mems and slab_mutex 704 * held after a sched RCU grace period. The slab is guaranteed to stay 705 * alive until @deact_fn is finished. This is to be used from 706 * __kmemcg_cache_deactivate(). 707 */ 708 void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, 709 void (*deact_fn)(struct kmem_cache *)) 710 { 711 if (WARN_ON_ONCE(is_root_cache(s)) || 712 WARN_ON_ONCE(s->memcg_params.deact_fn)) 713 return; 714 715 /* pin memcg so that @s doesn't get destroyed in the middle */ 716 css_get(&s->memcg_params.memcg->css); 717 718 s->memcg_params.deact_fn = deact_fn; 719 call_rcu_sched(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn); 720 } 721 722 void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) 723 { 724 int idx; 725 struct memcg_cache_array *arr; 726 struct kmem_cache *s, *c; 727 728 idx = memcg_cache_id(memcg); 729 730 get_online_cpus(); 731 get_online_mems(); 732 733 mutex_lock(&slab_mutex); 734 list_for_each_entry(s, &slab_root_caches, root_caches_node) { 735 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 736 lockdep_is_held(&slab_mutex)); 737 c = arr->entries[idx]; 738 if (!c) 739 continue; 740 741 __kmemcg_cache_deactivate(c); 742 arr->entries[idx] = NULL; 743 } 744 mutex_unlock(&slab_mutex); 745 746 put_online_mems(); 747 put_online_cpus(); 748 } 749 750 void memcg_destroy_kmem_caches(struct mem_cgroup *memcg) 751 { 752 struct kmem_cache *s, *s2; 753 754 get_online_cpus(); 755 get_online_mems(); 756 757 mutex_lock(&slab_mutex); 758 list_for_each_entry_safe(s, s2, &memcg->kmem_caches, 759 memcg_params.kmem_caches_node) { 760 /* 761 * The cgroup is about to be freed and therefore has no charges 762 * left. Hence, all its caches must be empty by now. 763 */ 764 BUG_ON(shutdown_cache(s)); 765 } 766 mutex_unlock(&slab_mutex); 767 768 put_online_mems(); 769 put_online_cpus(); 770 } 771 772 static int shutdown_memcg_caches(struct kmem_cache *s) 773 { 774 struct memcg_cache_array *arr; 775 struct kmem_cache *c, *c2; 776 LIST_HEAD(busy); 777 int i; 778 779 BUG_ON(!is_root_cache(s)); 780 781 /* 782 * First, shutdown active caches, i.e. caches that belong to online 783 * memory cgroups. 784 */ 785 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 786 lockdep_is_held(&slab_mutex)); 787 for_each_memcg_cache_index(i) { 788 c = arr->entries[i]; 789 if (!c) 790 continue; 791 if (shutdown_cache(c)) 792 /* 793 * The cache still has objects. Move it to a temporary 794 * list so as not to try to destroy it for a second 795 * time while iterating over inactive caches below. 796 */ 797 list_move(&c->memcg_params.children_node, &busy); 798 else 799 /* 800 * The cache is empty and will be destroyed soon. Clear 801 * the pointer to it in the memcg_caches array so that 802 * it will never be accessed even if the root cache 803 * stays alive. 804 */ 805 arr->entries[i] = NULL; 806 } 807 808 /* 809 * Second, shutdown all caches left from memory cgroups that are now 810 * offline. 811 */ 812 list_for_each_entry_safe(c, c2, &s->memcg_params.children, 813 memcg_params.children_node) 814 shutdown_cache(c); 815 816 list_splice(&busy, &s->memcg_params.children); 817 818 /* 819 * A cache being destroyed must be empty. In particular, this means 820 * that all per memcg caches attached to it must be empty too. 821 */ 822 if (!list_empty(&s->memcg_params.children)) 823 return -EBUSY; 824 return 0; 825 } 826 #else 827 static inline int shutdown_memcg_caches(struct kmem_cache *s) 828 { 829 return 0; 830 } 831 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */ 832 833 void slab_kmem_cache_release(struct kmem_cache *s) 834 { 835 __kmem_cache_release(s); 836 destroy_memcg_params(s); 837 kfree_const(s->name); 838 kmem_cache_free(kmem_cache, s); 839 } 840 841 void kmem_cache_destroy(struct kmem_cache *s) 842 { 843 int err; 844 845 if (unlikely(!s)) 846 return; 847 848 get_online_cpus(); 849 get_online_mems(); 850 851 mutex_lock(&slab_mutex); 852 853 s->refcount--; 854 if (s->refcount) 855 goto out_unlock; 856 857 err = shutdown_memcg_caches(s); 858 if (!err) 859 err = shutdown_cache(s); 860 861 if (err) { 862 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n", 863 s->name); 864 dump_stack(); 865 } 866 out_unlock: 867 mutex_unlock(&slab_mutex); 868 869 put_online_mems(); 870 put_online_cpus(); 871 } 872 EXPORT_SYMBOL(kmem_cache_destroy); 873 874 /** 875 * kmem_cache_shrink - Shrink a cache. 876 * @cachep: The cache to shrink. 877 * 878 * Releases as many slabs as possible for a cache. 879 * To help debugging, a zero exit status indicates all slabs were released. 880 */ 881 int kmem_cache_shrink(struct kmem_cache *cachep) 882 { 883 int ret; 884 885 get_online_cpus(); 886 get_online_mems(); 887 kasan_cache_shrink(cachep); 888 ret = __kmem_cache_shrink(cachep); 889 put_online_mems(); 890 put_online_cpus(); 891 return ret; 892 } 893 EXPORT_SYMBOL(kmem_cache_shrink); 894 895 bool slab_is_available(void) 896 { 897 return slab_state >= UP; 898 } 899 900 #ifndef CONFIG_SLOB 901 /* Create a cache during boot when no slab services are available yet */ 902 void __init create_boot_cache(struct kmem_cache *s, const char *name, 903 unsigned int size, slab_flags_t flags, 904 unsigned int useroffset, unsigned int usersize) 905 { 906 int err; 907 908 s->name = name; 909 s->size = s->object_size = size; 910 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); 911 s->useroffset = useroffset; 912 s->usersize = usersize; 913 914 slab_init_memcg_params(s); 915 916 err = __kmem_cache_create(s, flags); 917 918 if (err) 919 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n", 920 name, size, err); 921 922 s->refcount = -1; /* Exempt from merging for now */ 923 } 924 925 struct kmem_cache *__init create_kmalloc_cache(const char *name, 926 unsigned int size, slab_flags_t flags, 927 unsigned int useroffset, unsigned int usersize) 928 { 929 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 930 931 if (!s) 932 panic("Out of memory when creating slab %s\n", name); 933 934 create_boot_cache(s, name, size, flags, useroffset, usersize); 935 list_add(&s->list, &slab_caches); 936 memcg_link_cache(s); 937 s->refcount = 1; 938 return s; 939 } 940 941 struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1] __ro_after_init; 942 EXPORT_SYMBOL(kmalloc_caches); 943 944 #ifdef CONFIG_ZONE_DMA 945 struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1] __ro_after_init; 946 EXPORT_SYMBOL(kmalloc_dma_caches); 947 #endif 948 949 /* 950 * Conversion table for small slabs sizes / 8 to the index in the 951 * kmalloc array. This is necessary for slabs < 192 since we have non power 952 * of two cache sizes there. The size of larger slabs can be determined using 953 * fls. 954 */ 955 static u8 size_index[24] __ro_after_init = { 956 3, /* 8 */ 957 4, /* 16 */ 958 5, /* 24 */ 959 5, /* 32 */ 960 6, /* 40 */ 961 6, /* 48 */ 962 6, /* 56 */ 963 6, /* 64 */ 964 1, /* 72 */ 965 1, /* 80 */ 966 1, /* 88 */ 967 1, /* 96 */ 968 7, /* 104 */ 969 7, /* 112 */ 970 7, /* 120 */ 971 7, /* 128 */ 972 2, /* 136 */ 973 2, /* 144 */ 974 2, /* 152 */ 975 2, /* 160 */ 976 2, /* 168 */ 977 2, /* 176 */ 978 2, /* 184 */ 979 2 /* 192 */ 980 }; 981 982 static inline unsigned int size_index_elem(unsigned int bytes) 983 { 984 return (bytes - 1) / 8; 985 } 986 987 /* 988 * Find the kmem_cache structure that serves a given size of 989 * allocation 990 */ 991 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) 992 { 993 unsigned int index; 994 995 if (unlikely(size > KMALLOC_MAX_SIZE)) { 996 WARN_ON_ONCE(!(flags & __GFP_NOWARN)); 997 return NULL; 998 } 999 1000 if (size <= 192) { 1001 if (!size) 1002 return ZERO_SIZE_PTR; 1003 1004 index = size_index[size_index_elem(size)]; 1005 } else 1006 index = fls(size - 1); 1007 1008 #ifdef CONFIG_ZONE_DMA 1009 if (unlikely((flags & GFP_DMA))) 1010 return kmalloc_dma_caches[index]; 1011 1012 #endif 1013 return kmalloc_caches[index]; 1014 } 1015 1016 /* 1017 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 1018 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is 1019 * kmalloc-67108864. 1020 */ 1021 const struct kmalloc_info_struct kmalloc_info[] __initconst = { 1022 {NULL, 0}, {"kmalloc-96", 96}, 1023 {"kmalloc-192", 192}, {"kmalloc-8", 8}, 1024 {"kmalloc-16", 16}, {"kmalloc-32", 32}, 1025 {"kmalloc-64", 64}, {"kmalloc-128", 128}, 1026 {"kmalloc-256", 256}, {"kmalloc-512", 512}, 1027 {"kmalloc-1024", 1024}, {"kmalloc-2048", 2048}, 1028 {"kmalloc-4096", 4096}, {"kmalloc-8192", 8192}, 1029 {"kmalloc-16384", 16384}, {"kmalloc-32768", 32768}, 1030 {"kmalloc-65536", 65536}, {"kmalloc-131072", 131072}, 1031 {"kmalloc-262144", 262144}, {"kmalloc-524288", 524288}, 1032 {"kmalloc-1048576", 1048576}, {"kmalloc-2097152", 2097152}, 1033 {"kmalloc-4194304", 4194304}, {"kmalloc-8388608", 8388608}, 1034 {"kmalloc-16777216", 16777216}, {"kmalloc-33554432", 33554432}, 1035 {"kmalloc-67108864", 67108864} 1036 }; 1037 1038 /* 1039 * Patch up the size_index table if we have strange large alignment 1040 * requirements for the kmalloc array. This is only the case for 1041 * MIPS it seems. The standard arches will not generate any code here. 1042 * 1043 * Largest permitted alignment is 256 bytes due to the way we 1044 * handle the index determination for the smaller caches. 1045 * 1046 * Make sure that nothing crazy happens if someone starts tinkering 1047 * around with ARCH_KMALLOC_MINALIGN 1048 */ 1049 void __init setup_kmalloc_cache_index_table(void) 1050 { 1051 unsigned int i; 1052 1053 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 1054 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 1055 1056 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 1057 unsigned int elem = size_index_elem(i); 1058 1059 if (elem >= ARRAY_SIZE(size_index)) 1060 break; 1061 size_index[elem] = KMALLOC_SHIFT_LOW; 1062 } 1063 1064 if (KMALLOC_MIN_SIZE >= 64) { 1065 /* 1066 * The 96 byte size cache is not used if the alignment 1067 * is 64 byte. 1068 */ 1069 for (i = 64 + 8; i <= 96; i += 8) 1070 size_index[size_index_elem(i)] = 7; 1071 1072 } 1073 1074 if (KMALLOC_MIN_SIZE >= 128) { 1075 /* 1076 * The 192 byte sized cache is not used if the alignment 1077 * is 128 byte. Redirect kmalloc to use the 256 byte cache 1078 * instead. 1079 */ 1080 for (i = 128 + 8; i <= 192; i += 8) 1081 size_index[size_index_elem(i)] = 8; 1082 } 1083 } 1084 1085 static void __init new_kmalloc_cache(int idx, slab_flags_t flags) 1086 { 1087 kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name, 1088 kmalloc_info[idx].size, flags, 0, 1089 kmalloc_info[idx].size); 1090 } 1091 1092 /* 1093 * Create the kmalloc array. Some of the regular kmalloc arrays 1094 * may already have been created because they were needed to 1095 * enable allocations for slab creation. 1096 */ 1097 void __init create_kmalloc_caches(slab_flags_t flags) 1098 { 1099 int i; 1100 1101 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 1102 if (!kmalloc_caches[i]) 1103 new_kmalloc_cache(i, flags); 1104 1105 /* 1106 * Caches that are not of the two-to-the-power-of size. 1107 * These have to be created immediately after the 1108 * earlier power of two caches 1109 */ 1110 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) 1111 new_kmalloc_cache(1, flags); 1112 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) 1113 new_kmalloc_cache(2, flags); 1114 } 1115 1116 /* Kmalloc array is now usable */ 1117 slab_state = UP; 1118 1119 #ifdef CONFIG_ZONE_DMA 1120 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { 1121 struct kmem_cache *s = kmalloc_caches[i]; 1122 1123 if (s) { 1124 unsigned int size = kmalloc_size(i); 1125 char *n = kasprintf(GFP_NOWAIT, 1126 "dma-kmalloc-%u", size); 1127 1128 BUG_ON(!n); 1129 kmalloc_dma_caches[i] = create_kmalloc_cache(n, 1130 size, SLAB_CACHE_DMA | flags, 0, 0); 1131 } 1132 } 1133 #endif 1134 } 1135 #endif /* !CONFIG_SLOB */ 1136 1137 /* 1138 * To avoid unnecessary overhead, we pass through large allocation requests 1139 * directly to the page allocator. We use __GFP_COMP, because we will need to 1140 * know the allocation order to free the pages properly in kfree. 1141 */ 1142 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 1143 { 1144 void *ret; 1145 struct page *page; 1146 1147 flags |= __GFP_COMP; 1148 page = alloc_pages(flags, order); 1149 ret = page ? page_address(page) : NULL; 1150 kmemleak_alloc(ret, size, 1, flags); 1151 kasan_kmalloc_large(ret, size, flags); 1152 return ret; 1153 } 1154 EXPORT_SYMBOL(kmalloc_order); 1155 1156 #ifdef CONFIG_TRACING 1157 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) 1158 { 1159 void *ret = kmalloc_order(size, flags, order); 1160 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); 1161 return ret; 1162 } 1163 EXPORT_SYMBOL(kmalloc_order_trace); 1164 #endif 1165 1166 #ifdef CONFIG_SLAB_FREELIST_RANDOM 1167 /* Randomize a generic freelist */ 1168 static void freelist_randomize(struct rnd_state *state, unsigned int *list, 1169 unsigned int count) 1170 { 1171 unsigned int rand; 1172 unsigned int i; 1173 1174 for (i = 0; i < count; i++) 1175 list[i] = i; 1176 1177 /* Fisher-Yates shuffle */ 1178 for (i = count - 1; i > 0; i--) { 1179 rand = prandom_u32_state(state); 1180 rand %= (i + 1); 1181 swap(list[i], list[rand]); 1182 } 1183 } 1184 1185 /* Create a random sequence per cache */ 1186 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 1187 gfp_t gfp) 1188 { 1189 struct rnd_state state; 1190 1191 if (count < 2 || cachep->random_seq) 1192 return 0; 1193 1194 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); 1195 if (!cachep->random_seq) 1196 return -ENOMEM; 1197 1198 /* Get best entropy at this stage of boot */ 1199 prandom_seed_state(&state, get_random_long()); 1200 1201 freelist_randomize(&state, cachep->random_seq, count); 1202 return 0; 1203 } 1204 1205 /* Destroy the per-cache random freelist sequence */ 1206 void cache_random_seq_destroy(struct kmem_cache *cachep) 1207 { 1208 kfree(cachep->random_seq); 1209 cachep->random_seq = NULL; 1210 } 1211 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 1212 1213 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 1214 #ifdef CONFIG_SLAB 1215 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR) 1216 #else 1217 #define SLABINFO_RIGHTS S_IRUSR 1218 #endif 1219 1220 static void print_slabinfo_header(struct seq_file *m) 1221 { 1222 /* 1223 * Output format version, so at least we can change it 1224 * without _too_ many complaints. 1225 */ 1226 #ifdef CONFIG_DEBUG_SLAB 1227 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 1228 #else 1229 seq_puts(m, "slabinfo - version: 2.1\n"); 1230 #endif 1231 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); 1232 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 1233 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 1234 #ifdef CONFIG_DEBUG_SLAB 1235 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 1236 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 1237 #endif 1238 seq_putc(m, '\n'); 1239 } 1240 1241 void *slab_start(struct seq_file *m, loff_t *pos) 1242 { 1243 mutex_lock(&slab_mutex); 1244 return seq_list_start(&slab_root_caches, *pos); 1245 } 1246 1247 void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1248 { 1249 return seq_list_next(p, &slab_root_caches, pos); 1250 } 1251 1252 void slab_stop(struct seq_file *m, void *p) 1253 { 1254 mutex_unlock(&slab_mutex); 1255 } 1256 1257 static void 1258 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) 1259 { 1260 struct kmem_cache *c; 1261 struct slabinfo sinfo; 1262 1263 if (!is_root_cache(s)) 1264 return; 1265 1266 for_each_memcg_cache(c, s) { 1267 memset(&sinfo, 0, sizeof(sinfo)); 1268 get_slabinfo(c, &sinfo); 1269 1270 info->active_slabs += sinfo.active_slabs; 1271 info->num_slabs += sinfo.num_slabs; 1272 info->shared_avail += sinfo.shared_avail; 1273 info->active_objs += sinfo.active_objs; 1274 info->num_objs += sinfo.num_objs; 1275 } 1276 } 1277 1278 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1279 { 1280 struct slabinfo sinfo; 1281 1282 memset(&sinfo, 0, sizeof(sinfo)); 1283 get_slabinfo(s, &sinfo); 1284 1285 memcg_accumulate_slabinfo(s, &sinfo); 1286 1287 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1288 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, 1289 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1290 1291 seq_printf(m, " : tunables %4u %4u %4u", 1292 sinfo.limit, sinfo.batchcount, sinfo.shared); 1293 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1294 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1295 slabinfo_show_stats(m, s); 1296 seq_putc(m, '\n'); 1297 } 1298 1299 static int slab_show(struct seq_file *m, void *p) 1300 { 1301 struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node); 1302 1303 if (p == slab_root_caches.next) 1304 print_slabinfo_header(m); 1305 cache_show(s, m); 1306 return 0; 1307 } 1308 1309 void dump_unreclaimable_slab(void) 1310 { 1311 struct kmem_cache *s, *s2; 1312 struct slabinfo sinfo; 1313 1314 /* 1315 * Here acquiring slab_mutex is risky since we don't prefer to get 1316 * sleep in oom path. But, without mutex hold, it may introduce a 1317 * risk of crash. 1318 * Use mutex_trylock to protect the list traverse, dump nothing 1319 * without acquiring the mutex. 1320 */ 1321 if (!mutex_trylock(&slab_mutex)) { 1322 pr_warn("excessive unreclaimable slab but cannot dump stats\n"); 1323 return; 1324 } 1325 1326 pr_info("Unreclaimable slab info:\n"); 1327 pr_info("Name Used Total\n"); 1328 1329 list_for_each_entry_safe(s, s2, &slab_caches, list) { 1330 if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT)) 1331 continue; 1332 1333 get_slabinfo(s, &sinfo); 1334 1335 if (sinfo.num_objs > 0) 1336 pr_info("%-17s %10luKB %10luKB\n", cache_name(s), 1337 (sinfo.active_objs * s->size) / 1024, 1338 (sinfo.num_objs * s->size) / 1024); 1339 } 1340 mutex_unlock(&slab_mutex); 1341 } 1342 1343 #if defined(CONFIG_MEMCG) 1344 void *memcg_slab_start(struct seq_file *m, loff_t *pos) 1345 { 1346 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1347 1348 mutex_lock(&slab_mutex); 1349 return seq_list_start(&memcg->kmem_caches, *pos); 1350 } 1351 1352 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos) 1353 { 1354 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1355 1356 return seq_list_next(p, &memcg->kmem_caches, pos); 1357 } 1358 1359 void memcg_slab_stop(struct seq_file *m, void *p) 1360 { 1361 mutex_unlock(&slab_mutex); 1362 } 1363 1364 int memcg_slab_show(struct seq_file *m, void *p) 1365 { 1366 struct kmem_cache *s = list_entry(p, struct kmem_cache, 1367 memcg_params.kmem_caches_node); 1368 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1369 1370 if (p == memcg->kmem_caches.next) 1371 print_slabinfo_header(m); 1372 cache_show(s, m); 1373 return 0; 1374 } 1375 #endif 1376 1377 /* 1378 * slabinfo_op - iterator that generates /proc/slabinfo 1379 * 1380 * Output layout: 1381 * cache-name 1382 * num-active-objs 1383 * total-objs 1384 * object size 1385 * num-active-slabs 1386 * total-slabs 1387 * num-pages-per-slab 1388 * + further values on SMP and with statistics enabled 1389 */ 1390 static const struct seq_operations slabinfo_op = { 1391 .start = slab_start, 1392 .next = slab_next, 1393 .stop = slab_stop, 1394 .show = slab_show, 1395 }; 1396 1397 static int slabinfo_open(struct inode *inode, struct file *file) 1398 { 1399 return seq_open(file, &slabinfo_op); 1400 } 1401 1402 static const struct file_operations proc_slabinfo_operations = { 1403 .open = slabinfo_open, 1404 .read = seq_read, 1405 .write = slabinfo_write, 1406 .llseek = seq_lseek, 1407 .release = seq_release, 1408 }; 1409 1410 static int __init slab_proc_init(void) 1411 { 1412 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, 1413 &proc_slabinfo_operations); 1414 return 0; 1415 } 1416 module_init(slab_proc_init); 1417 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ 1418 1419 static __always_inline void *__do_krealloc(const void *p, size_t new_size, 1420 gfp_t flags) 1421 { 1422 void *ret; 1423 size_t ks = 0; 1424 1425 if (p) 1426 ks = ksize(p); 1427 1428 if (ks >= new_size) { 1429 kasan_krealloc((void *)p, new_size, flags); 1430 return (void *)p; 1431 } 1432 1433 ret = kmalloc_track_caller(new_size, flags); 1434 if (ret && p) 1435 memcpy(ret, p, ks); 1436 1437 return ret; 1438 } 1439 1440 /** 1441 * __krealloc - like krealloc() but don't free @p. 1442 * @p: object to reallocate memory for. 1443 * @new_size: how many bytes of memory are required. 1444 * @flags: the type of memory to allocate. 1445 * 1446 * This function is like krealloc() except it never frees the originally 1447 * allocated buffer. Use this if you don't want to free the buffer immediately 1448 * like, for example, with RCU. 1449 */ 1450 void *__krealloc(const void *p, size_t new_size, gfp_t flags) 1451 { 1452 if (unlikely(!new_size)) 1453 return ZERO_SIZE_PTR; 1454 1455 return __do_krealloc(p, new_size, flags); 1456 1457 } 1458 EXPORT_SYMBOL(__krealloc); 1459 1460 /** 1461 * krealloc - reallocate memory. The contents will remain unchanged. 1462 * @p: object to reallocate memory for. 1463 * @new_size: how many bytes of memory are required. 1464 * @flags: the type of memory to allocate. 1465 * 1466 * The contents of the object pointed to are preserved up to the 1467 * lesser of the new and old sizes. If @p is %NULL, krealloc() 1468 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a 1469 * %NULL pointer, the object pointed to is freed. 1470 */ 1471 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1472 { 1473 void *ret; 1474 1475 if (unlikely(!new_size)) { 1476 kfree(p); 1477 return ZERO_SIZE_PTR; 1478 } 1479 1480 ret = __do_krealloc(p, new_size, flags); 1481 if (ret && p != ret) 1482 kfree(p); 1483 1484 return ret; 1485 } 1486 EXPORT_SYMBOL(krealloc); 1487 1488 /** 1489 * kzfree - like kfree but zero memory 1490 * @p: object to free memory of 1491 * 1492 * The memory of the object @p points to is zeroed before freed. 1493 * If @p is %NULL, kzfree() does nothing. 1494 * 1495 * Note: this function zeroes the whole allocated buffer which can be a good 1496 * deal bigger than the requested buffer size passed to kmalloc(). So be 1497 * careful when using this function in performance sensitive code. 1498 */ 1499 void kzfree(const void *p) 1500 { 1501 size_t ks; 1502 void *mem = (void *)p; 1503 1504 if (unlikely(ZERO_OR_NULL_PTR(mem))) 1505 return; 1506 ks = ksize(mem); 1507 memset(mem, 0, ks); 1508 kfree(mem); 1509 } 1510 EXPORT_SYMBOL(kzfree); 1511 1512 /* Tracepoints definitions. */ 1513 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1514 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1515 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); 1516 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); 1517 EXPORT_TRACEPOINT_SYMBOL(kfree); 1518 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1519 1520 int should_failslab(struct kmem_cache *s, gfp_t gfpflags) 1521 { 1522 if (__should_failslab(s, gfpflags)) 1523 return -ENOMEM; 1524 return 0; 1525 } 1526 ALLOW_ERROR_INJECTION(should_failslab, ERRNO); 1527