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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SLOB Allocator: Simple List Of Blocks
4  *
5  * Matt Mackall <mpm@selenic.com> 12/30/03
6  *
7  * NUMA support by Paul Mundt, 2007.
8  *
9  * How SLOB works:
10  *
11  * The core of SLOB is a traditional K&R style heap allocator, with
12  * support for returning aligned objects. The granularity of this
13  * allocator is as little as 2 bytes, however typically most architectures
14  * will require 4 bytes on 32-bit and 8 bytes on 64-bit.
15  *
16  * The slob heap is a set of linked list of pages from alloc_pages(),
17  * and within each page, there is a singly-linked list of free blocks
18  * (slob_t). The heap is grown on demand. To reduce fragmentation,
19  * heap pages are segregated into three lists, with objects less than
20  * 256 bytes, objects less than 1024 bytes, and all other objects.
21  *
22  * Allocation from heap involves first searching for a page with
23  * sufficient free blocks (using a next-fit-like approach) followed by
24  * a first-fit scan of the page. Deallocation inserts objects back
25  * into the free list in address order, so this is effectively an
26  * address-ordered first fit.
27  *
28  * Above this is an implementation of kmalloc/kfree. Blocks returned
29  * from kmalloc are prepended with a 4-byte header with the kmalloc size.
30  * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
31  * alloc_pages() directly, allocating compound pages so the page order
32  * does not have to be separately tracked.
33  * These objects are detected in kfree() because PageSlab()
34  * is false for them.
35  *
36  * SLAB is emulated on top of SLOB by simply calling constructors and
37  * destructors for every SLAB allocation. Objects are returned with the
38  * 4-byte alignment unless the SLAB_HWCACHE_ALIGN flag is set, in which
39  * case the low-level allocator will fragment blocks to create the proper
40  * alignment. Again, objects of page-size or greater are allocated by
41  * calling alloc_pages(). As SLAB objects know their size, no separate
42  * size bookkeeping is necessary and there is essentially no allocation
43  * space overhead, and compound pages aren't needed for multi-page
44  * allocations.
45  *
46  * NUMA support in SLOB is fairly simplistic, pushing most of the real
47  * logic down to the page allocator, and simply doing the node accounting
48  * on the upper levels. In the event that a node id is explicitly
49  * provided, __alloc_pages_node() with the specified node id is used
50  * instead. The common case (or when the node id isn't explicitly provided)
51  * will default to the current node, as per numa_node_id().
52  *
53  * Node aware pages are still inserted in to the global freelist, and
54  * these are scanned for by matching against the node id encoded in the
55  * page flags. As a result, block allocations that can be satisfied from
56  * the freelist will only be done so on pages residing on the same node,
57  * in order to prevent random node placement.
58  */
59 
60 #include <linux/kernel.h>
61 #include <linux/slab.h>
62 
63 #include <linux/mm.h>
64 #include <linux/swap.h> /* struct reclaim_state */
65 #include <linux/cache.h>
66 #include <linux/init.h>
67 #include <linux/export.h>
68 #include <linux/rcupdate.h>
69 #include <linux/list.h>
70 #include <linux/kmemleak.h>
71 
72 #include <trace/events/kmem.h>
73 
74 #include <linux/atomic.h>
75 
76 #include "slab.h"
77 /*
78  * slob_block has a field 'units', which indicates size of block if +ve,
79  * or offset of next block if -ve (in SLOB_UNITs).
80  *
81  * Free blocks of size 1 unit simply contain the offset of the next block.
82  * Those with larger size contain their size in the first SLOB_UNIT of
83  * memory, and the offset of the next free block in the second SLOB_UNIT.
84  */
85 #if PAGE_SIZE <= (32767 * 2)
86 typedef s16 slobidx_t;
87 #else
88 typedef s32 slobidx_t;
89 #endif
90 
91 struct slob_block {
92 	slobidx_t units;
93 };
94 typedef struct slob_block slob_t;
95 
96 /*
97  * All partially free slob pages go on these lists.
98  */
99 #define SLOB_BREAK1 256
100 #define SLOB_BREAK2 1024
101 static LIST_HEAD(free_slob_small);
102 static LIST_HEAD(free_slob_medium);
103 static LIST_HEAD(free_slob_large);
104 
105 /*
106  * slob_page_free: true for pages on free_slob_pages list.
107  */
slob_page_free(struct page * sp)108 static inline int slob_page_free(struct page *sp)
109 {
110 	return PageSlobFree(sp);
111 }
112 
set_slob_page_free(struct page * sp,struct list_head * list)113 static void set_slob_page_free(struct page *sp, struct list_head *list)
114 {
115 	list_add(&sp->slab_list, list);
116 	__SetPageSlobFree(sp);
117 }
118 
clear_slob_page_free(struct page * sp)119 static inline void clear_slob_page_free(struct page *sp)
120 {
121 	list_del(&sp->slab_list);
122 	__ClearPageSlobFree(sp);
123 }
124 
125 #define SLOB_UNIT sizeof(slob_t)
126 #define SLOB_UNITS(size) DIV_ROUND_UP(size, SLOB_UNIT)
127 
128 /*
129  * struct slob_rcu is inserted at the tail of allocated slob blocks, which
130  * were created with a SLAB_TYPESAFE_BY_RCU slab. slob_rcu is used to free
131  * the block using call_rcu.
132  */
133 struct slob_rcu {
134 	struct rcu_head head;
135 	int size;
136 };
137 
138 /*
139  * slob_lock protects all slob allocator structures.
140  */
141 static DEFINE_SPINLOCK(slob_lock);
142 
143 /*
144  * Encode the given size and next info into a free slob block s.
145  */
set_slob(slob_t * s,slobidx_t size,slob_t * next)146 static void set_slob(slob_t *s, slobidx_t size, slob_t *next)
147 {
148 	slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
149 	slobidx_t offset = next - base;
150 
151 	if (size > 1) {
152 		s[0].units = size;
153 		s[1].units = offset;
154 	} else
155 		s[0].units = -offset;
156 }
157 
158 /*
159  * Return the size of a slob block.
160  */
slob_units(slob_t * s)161 static slobidx_t slob_units(slob_t *s)
162 {
163 	if (s->units > 0)
164 		return s->units;
165 	return 1;
166 }
167 
168 /*
169  * Return the next free slob block pointer after this one.
170  */
slob_next(slob_t * s)171 static slob_t *slob_next(slob_t *s)
172 {
173 	slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
174 	slobidx_t next;
175 
176 	if (s[0].units < 0)
177 		next = -s[0].units;
178 	else
179 		next = s[1].units;
180 	return base+next;
181 }
182 
183 /*
184  * Returns true if s is the last free block in its page.
185  */
slob_last(slob_t * s)186 static int slob_last(slob_t *s)
187 {
188 	return !((unsigned long)slob_next(s) & ~PAGE_MASK);
189 }
190 
slob_new_pages(gfp_t gfp,int order,int node)191 static void *slob_new_pages(gfp_t gfp, int order, int node)
192 {
193 	struct page *page;
194 
195 #ifdef CONFIG_NUMA
196 	if (node != NUMA_NO_NODE)
197 		page = __alloc_pages_node(node, gfp, order);
198 	else
199 #endif
200 		page = alloc_pages(gfp, order);
201 
202 	if (!page)
203 		return NULL;
204 
205 	mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
206 			    PAGE_SIZE << order);
207 	return page_address(page);
208 }
209 
slob_free_pages(void * b,int order)210 static void slob_free_pages(void *b, int order)
211 {
212 	struct page *sp = virt_to_page(b);
213 
214 	if (current->reclaim_state)
215 		current->reclaim_state->reclaimed_slab += 1 << order;
216 
217 	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
218 			    -(PAGE_SIZE << order));
219 	__free_pages(sp, order);
220 }
221 
222 /*
223  * slob_page_alloc() - Allocate a slob block within a given slob_page sp.
224  * @sp: Page to look in.
225  * @size: Size of the allocation.
226  * @align: Allocation alignment.
227  * @align_offset: Offset in the allocated block that will be aligned.
228  * @page_removed_from_list: Return parameter.
229  *
230  * Tries to find a chunk of memory at least @size bytes big within @page.
231  *
232  * Return: Pointer to memory if allocated, %NULL otherwise.  If the
233  *         allocation fills up @page then the page is removed from the
234  *         freelist, in this case @page_removed_from_list will be set to
235  *         true (set to false otherwise).
236  */
slob_page_alloc(struct page * sp,size_t size,int align,int align_offset,bool * page_removed_from_list)237 static void *slob_page_alloc(struct page *sp, size_t size, int align,
238 			      int align_offset, bool *page_removed_from_list)
239 {
240 	slob_t *prev, *cur, *aligned = NULL;
241 	int delta = 0, units = SLOB_UNITS(size);
242 
243 	*page_removed_from_list = false;
244 	for (prev = NULL, cur = sp->freelist; ; prev = cur, cur = slob_next(cur)) {
245 		slobidx_t avail = slob_units(cur);
246 
247 		/*
248 		 * 'aligned' will hold the address of the slob block so that the
249 		 * address 'aligned'+'align_offset' is aligned according to the
250 		 * 'align' parameter. This is for kmalloc() which prepends the
251 		 * allocated block with its size, so that the block itself is
252 		 * aligned when needed.
253 		 */
254 		if (align) {
255 			aligned = (slob_t *)
256 				(ALIGN((unsigned long)cur + align_offset, align)
257 				 - align_offset);
258 			delta = aligned - cur;
259 		}
260 		if (avail >= units + delta) { /* room enough? */
261 			slob_t *next;
262 
263 			if (delta) { /* need to fragment head to align? */
264 				next = slob_next(cur);
265 				set_slob(aligned, avail - delta, next);
266 				set_slob(cur, delta, aligned);
267 				prev = cur;
268 				cur = aligned;
269 				avail = slob_units(cur);
270 			}
271 
272 			next = slob_next(cur);
273 			if (avail == units) { /* exact fit? unlink. */
274 				if (prev)
275 					set_slob(prev, slob_units(prev), next);
276 				else
277 					sp->freelist = next;
278 			} else { /* fragment */
279 				if (prev)
280 					set_slob(prev, slob_units(prev), cur + units);
281 				else
282 					sp->freelist = cur + units;
283 				set_slob(cur + units, avail - units, next);
284 			}
285 
286 			sp->units -= units;
287 			if (!sp->units) {
288 				clear_slob_page_free(sp);
289 				*page_removed_from_list = true;
290 			}
291 			return cur;
292 		}
293 		if (slob_last(cur))
294 			return NULL;
295 	}
296 }
297 
298 /*
299  * slob_alloc: entry point into the slob allocator.
300  */
slob_alloc(size_t size,gfp_t gfp,int align,int node,int align_offset)301 static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
302 							int align_offset)
303 {
304 	struct page *sp;
305 	struct list_head *slob_list;
306 	slob_t *b = NULL;
307 	unsigned long flags;
308 	bool _unused;
309 
310 	if (size < SLOB_BREAK1)
311 		slob_list = &free_slob_small;
312 	else if (size < SLOB_BREAK2)
313 		slob_list = &free_slob_medium;
314 	else
315 		slob_list = &free_slob_large;
316 
317 	spin_lock_irqsave(&slob_lock, flags);
318 	/* Iterate through each partially free page, try to find room */
319 	list_for_each_entry(sp, slob_list, slab_list) {
320 		bool page_removed_from_list = false;
321 #ifdef CONFIG_NUMA
322 		/*
323 		 * If there's a node specification, search for a partial
324 		 * page with a matching node id in the freelist.
325 		 */
326 		if (node != NUMA_NO_NODE && page_to_nid(sp) != node)
327 			continue;
328 #endif
329 		/* Enough room on this page? */
330 		if (sp->units < SLOB_UNITS(size))
331 			continue;
332 
333 		b = slob_page_alloc(sp, size, align, align_offset, &page_removed_from_list);
334 		if (!b)
335 			continue;
336 
337 		/*
338 		 * If slob_page_alloc() removed sp from the list then we
339 		 * cannot call list functions on sp.  If so allocation
340 		 * did not fragment the page anyway so optimisation is
341 		 * unnecessary.
342 		 */
343 		if (!page_removed_from_list) {
344 			/*
345 			 * Improve fragment distribution and reduce our average
346 			 * search time by starting our next search here. (see
347 			 * Knuth vol 1, sec 2.5, pg 449)
348 			 */
349 			if (!list_is_first(&sp->slab_list, slob_list))
350 				list_rotate_to_front(&sp->slab_list, slob_list);
351 		}
352 		break;
353 	}
354 	spin_unlock_irqrestore(&slob_lock, flags);
355 
356 	/* Not enough space: must allocate a new page */
357 	if (!b) {
358 		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
359 		if (!b)
360 			return NULL;
361 		sp = virt_to_page(b);
362 		__SetPageSlab(sp);
363 
364 		spin_lock_irqsave(&slob_lock, flags);
365 		sp->units = SLOB_UNITS(PAGE_SIZE);
366 		sp->freelist = b;
367 		INIT_LIST_HEAD(&sp->slab_list);
368 		set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE));
369 		set_slob_page_free(sp, slob_list);
370 		b = slob_page_alloc(sp, size, align, align_offset, &_unused);
371 		BUG_ON(!b);
372 		spin_unlock_irqrestore(&slob_lock, flags);
373 	}
374 	if (unlikely(gfp & __GFP_ZERO))
375 		memset(b, 0, size);
376 	return b;
377 }
378 
379 /*
380  * slob_free: entry point into the slob allocator.
381  */
slob_free(void * block,int size)382 static void slob_free(void *block, int size)
383 {
384 	struct page *sp;
385 	slob_t *prev, *next, *b = (slob_t *)block;
386 	slobidx_t units;
387 	unsigned long flags;
388 	struct list_head *slob_list;
389 
390 	if (unlikely(ZERO_OR_NULL_PTR(block)))
391 		return;
392 	BUG_ON(!size);
393 
394 	sp = virt_to_page(block);
395 	units = SLOB_UNITS(size);
396 
397 	spin_lock_irqsave(&slob_lock, flags);
398 
399 	if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
400 		/* Go directly to page allocator. Do not pass slob allocator */
401 		if (slob_page_free(sp))
402 			clear_slob_page_free(sp);
403 		spin_unlock_irqrestore(&slob_lock, flags);
404 		__ClearPageSlab(sp);
405 		page_mapcount_reset(sp);
406 		slob_free_pages(b, 0);
407 		return;
408 	}
409 
410 	if (!slob_page_free(sp)) {
411 		/* This slob page is about to become partially free. Easy! */
412 		sp->units = units;
413 		sp->freelist = b;
414 		set_slob(b, units,
415 			(void *)((unsigned long)(b +
416 					SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
417 		if (size < SLOB_BREAK1)
418 			slob_list = &free_slob_small;
419 		else if (size < SLOB_BREAK2)
420 			slob_list = &free_slob_medium;
421 		else
422 			slob_list = &free_slob_large;
423 		set_slob_page_free(sp, slob_list);
424 		goto out;
425 	}
426 
427 	/*
428 	 * Otherwise the page is already partially free, so find reinsertion
429 	 * point.
430 	 */
431 	sp->units += units;
432 
433 	if (b < (slob_t *)sp->freelist) {
434 		if (b + units == sp->freelist) {
435 			units += slob_units(sp->freelist);
436 			sp->freelist = slob_next(sp->freelist);
437 		}
438 		set_slob(b, units, sp->freelist);
439 		sp->freelist = b;
440 	} else {
441 		prev = sp->freelist;
442 		next = slob_next(prev);
443 		while (b > next) {
444 			prev = next;
445 			next = slob_next(prev);
446 		}
447 
448 		if (!slob_last(prev) && b + units == next) {
449 			units += slob_units(next);
450 			set_slob(b, units, slob_next(next));
451 		} else
452 			set_slob(b, units, next);
453 
454 		if (prev + slob_units(prev) == b) {
455 			units = slob_units(b) + slob_units(prev);
456 			set_slob(prev, units, slob_next(b));
457 		} else
458 			set_slob(prev, slob_units(prev), b);
459 	}
460 out:
461 	spin_unlock_irqrestore(&slob_lock, flags);
462 }
463 
464 #ifdef CONFIG_PRINTK
__kmem_obj_info(struct kmem_obj_info * kpp,void * object,struct page * page)465 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
466 {
467 	kpp->kp_ptr = object;
468 	kpp->kp_page = page;
469 }
470 #endif
471 
472 /*
473  * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.
474  */
475 
476 static __always_inline void *
__do_kmalloc_node(size_t size,gfp_t gfp,int node,unsigned long caller)477 __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
478 {
479 	unsigned int *m;
480 	unsigned int minalign;
481 	void *ret;
482 
483 	minalign = max_t(unsigned int, ARCH_KMALLOC_MINALIGN,
484 			 arch_slab_minalign());
485 	gfp &= gfp_allowed_mask;
486 
487 	might_alloc(gfp);
488 
489 	if (size < PAGE_SIZE - minalign) {
490 		int align = minalign;
491 
492 		/*
493 		 * For power of two sizes, guarantee natural alignment for
494 		 * kmalloc()'d objects.
495 		 */
496 		if (is_power_of_2(size))
497 			align = max_t(unsigned int, minalign, size);
498 
499 		if (!size)
500 			return ZERO_SIZE_PTR;
501 
502 		m = slob_alloc(size + minalign, gfp, align, node, minalign);
503 
504 		if (!m)
505 			return NULL;
506 		*m = size;
507 		ret = (void *)m + minalign;
508 
509 		trace_kmalloc_node(caller, ret,
510 				   size, size + minalign, gfp, node);
511 	} else {
512 		unsigned int order = get_order(size);
513 
514 		if (likely(order))
515 			gfp |= __GFP_COMP;
516 		ret = slob_new_pages(gfp, order, node);
517 
518 		trace_kmalloc_node(caller, ret,
519 				   size, PAGE_SIZE << order, gfp, node);
520 	}
521 
522 	kmemleak_alloc(ret, size, 1, gfp);
523 	return ret;
524 }
525 
__kmalloc(size_t size,gfp_t gfp)526 void *__kmalloc(size_t size, gfp_t gfp)
527 {
528 	return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, _RET_IP_);
529 }
530 EXPORT_SYMBOL(__kmalloc);
531 
__kmalloc_track_caller(size_t size,gfp_t gfp,unsigned long caller)532 void *__kmalloc_track_caller(size_t size, gfp_t gfp, unsigned long caller)
533 {
534 	return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, caller);
535 }
536 EXPORT_SYMBOL(__kmalloc_track_caller);
537 
538 #ifdef CONFIG_NUMA
__kmalloc_node_track_caller(size_t size,gfp_t gfp,int node,unsigned long caller)539 void *__kmalloc_node_track_caller(size_t size, gfp_t gfp,
540 					int node, unsigned long caller)
541 {
542 	return __do_kmalloc_node(size, gfp, node, caller);
543 }
544 EXPORT_SYMBOL(__kmalloc_node_track_caller);
545 #endif
546 
kfree(const void * block)547 void kfree(const void *block)
548 {
549 	struct page *sp;
550 
551 	trace_kfree(_RET_IP_, block);
552 
553 	if (unlikely(ZERO_OR_NULL_PTR(block)))
554 		return;
555 	kmemleak_free(block);
556 
557 	sp = virt_to_page(block);
558 	if (PageSlab(sp)) {
559 		unsigned int align = max_t(unsigned int,
560 					   ARCH_KMALLOC_MINALIGN,
561 					   arch_slab_minalign());
562 		unsigned int *m = (unsigned int *)(block - align);
563 
564 		slob_free(m, *m + align);
565 	} else {
566 		unsigned int order = compound_order(sp);
567 		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
568 				    -(PAGE_SIZE << order));
569 		__free_pages(sp, order);
570 
571 	}
572 }
573 EXPORT_SYMBOL(kfree);
574 
575 /* can't use ksize for kmem_cache_alloc memory, only kmalloc */
__ksize(const void * block)576 size_t __ksize(const void *block)
577 {
578 	struct page *sp;
579 	unsigned int align;
580 	unsigned int *m;
581 
582 	BUG_ON(!block);
583 	if (unlikely(block == ZERO_SIZE_PTR))
584 		return 0;
585 
586 	sp = virt_to_page(block);
587 	if (unlikely(!PageSlab(sp)))
588 		return page_size(sp);
589 
590 	align = max_t(unsigned int, ARCH_KMALLOC_MINALIGN,
591 		      arch_slab_minalign());
592 	m = (unsigned int *)(block - align);
593 	return SLOB_UNITS(*m) * SLOB_UNIT;
594 }
595 EXPORT_SYMBOL(__ksize);
596 
__kmem_cache_create(struct kmem_cache * c,slab_flags_t flags)597 int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
598 {
599 	if (flags & SLAB_TYPESAFE_BY_RCU) {
600 		/* leave room for rcu footer at the end of object */
601 		c->size += sizeof(struct slob_rcu);
602 	}
603 	c->flags = flags;
604 	return 0;
605 }
606 
slob_alloc_node(struct kmem_cache * c,gfp_t flags,int node)607 static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
608 {
609 	void *b;
610 
611 	flags &= gfp_allowed_mask;
612 
613 	might_alloc(flags);
614 
615 	if (c->size < PAGE_SIZE) {
616 		b = slob_alloc(c->size, flags, c->align, node, 0);
617 		trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size,
618 					    SLOB_UNITS(c->size) * SLOB_UNIT,
619 					    flags, node);
620 	} else {
621 		b = slob_new_pages(flags, get_order(c->size), node);
622 		trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size,
623 					    PAGE_SIZE << get_order(c->size),
624 					    flags, node);
625 	}
626 
627 	if (b && c->ctor) {
628 		WARN_ON_ONCE(flags & __GFP_ZERO);
629 		c->ctor(b);
630 	}
631 
632 	kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);
633 	return b;
634 }
635 
kmem_cache_alloc(struct kmem_cache * cachep,gfp_t flags)636 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
637 {
638 	return slob_alloc_node(cachep, flags, NUMA_NO_NODE);
639 }
640 EXPORT_SYMBOL(kmem_cache_alloc);
641 
642 #ifdef CONFIG_NUMA
__kmalloc_node(size_t size,gfp_t gfp,int node)643 void *__kmalloc_node(size_t size, gfp_t gfp, int node)
644 {
645 	return __do_kmalloc_node(size, gfp, node, _RET_IP_);
646 }
647 EXPORT_SYMBOL(__kmalloc_node);
648 
kmem_cache_alloc_node(struct kmem_cache * cachep,gfp_t gfp,int node)649 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t gfp, int node)
650 {
651 	return slob_alloc_node(cachep, gfp, node);
652 }
653 EXPORT_SYMBOL(kmem_cache_alloc_node);
654 #endif
655 
__kmem_cache_free(void * b,int size)656 static void __kmem_cache_free(void *b, int size)
657 {
658 	if (size < PAGE_SIZE)
659 		slob_free(b, size);
660 	else
661 		slob_free_pages(b, get_order(size));
662 }
663 
kmem_rcu_free(struct rcu_head * head)664 static void kmem_rcu_free(struct rcu_head *head)
665 {
666 	struct slob_rcu *slob_rcu = (struct slob_rcu *)head;
667 	void *b = (void *)slob_rcu - (slob_rcu->size - sizeof(struct slob_rcu));
668 
669 	__kmem_cache_free(b, slob_rcu->size);
670 }
671 
kmem_cache_free(struct kmem_cache * c,void * b)672 void kmem_cache_free(struct kmem_cache *c, void *b)
673 {
674 	kmemleak_free_recursive(b, c->flags);
675 	if (unlikely(c->flags & SLAB_TYPESAFE_BY_RCU)) {
676 		struct slob_rcu *slob_rcu;
677 		slob_rcu = b + (c->size - sizeof(struct slob_rcu));
678 		slob_rcu->size = c->size;
679 		call_rcu(&slob_rcu->head, kmem_rcu_free);
680 	} else {
681 		__kmem_cache_free(b, c->size);
682 	}
683 
684 	trace_kmem_cache_free(_RET_IP_, b, c->name);
685 }
686 EXPORT_SYMBOL(kmem_cache_free);
687 
kmem_cache_free_bulk(struct kmem_cache * s,size_t size,void ** p)688 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
689 {
690 	__kmem_cache_free_bulk(s, size, p);
691 }
692 EXPORT_SYMBOL(kmem_cache_free_bulk);
693 
kmem_cache_alloc_bulk(struct kmem_cache * s,gfp_t flags,size_t size,void ** p)694 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
695 								void **p)
696 {
697 	return __kmem_cache_alloc_bulk(s, flags, size, p);
698 }
699 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
700 
__kmem_cache_shutdown(struct kmem_cache * c)701 int __kmem_cache_shutdown(struct kmem_cache *c)
702 {
703 	/* No way to check for remaining objects */
704 	return 0;
705 }
706 
__kmem_cache_release(struct kmem_cache * c)707 void __kmem_cache_release(struct kmem_cache *c)
708 {
709 }
710 
__kmem_cache_shrink(struct kmem_cache * d)711 int __kmem_cache_shrink(struct kmem_cache *d)
712 {
713 	return 0;
714 }
715 
716 struct kmem_cache kmem_cache_boot = {
717 	.name = "kmem_cache",
718 	.size = sizeof(struct kmem_cache),
719 	.flags = SLAB_PANIC,
720 	.align = ARCH_KMALLOC_MINALIGN,
721 };
722 
kmem_cache_init(void)723 void __init kmem_cache_init(void)
724 {
725 	kmem_cache = &kmem_cache_boot;
726 	slab_state = UP;
727 }
728 
kmem_cache_init_late(void)729 void __init kmem_cache_init_late(void)
730 {
731 	slab_state = FULL;
732 }
733