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1/*
2 * Basic general purpose allocator for managing special purpose
3 * memory, for example, memory that is not managed by the regular
4 * kmalloc/kfree interface. Uses for this includes on-device special
5 * memory, uncached memory etc.
6 *
7 * It is safe to use the allocator in NMI handlers and other special
8 * unblockable contexts that could otherwise deadlock on locks. This
9 * is implemented by using atomic operations and retries on any
10 * conflicts. The disadvantage is that there may be livelocks in
11 * extreme cases. For better scalability, one allocator can be used
12 * for each CPU.
13 *
14 * The lockless operation only works if there is enough memory
15 * available. If new memory is added to the pool a lock has to be
16 * still taken. So any user relying on locklessness has to ensure
17 * that sufficient memory is preallocated.
18 *
19 * The basic atomic operation of this allocator is cmpxchg on long.
20 * On architectures that don't have NMI-safe cmpxchg implementation,
21 * the allocator can NOT be used in NMI handler. So code uses the
22 * allocator in NMI handler should depend on
23 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
24 *
25 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
26 *
27 * This source code is licensed under the GNU General Public License,
28 * Version 2. See the file COPYING for more details.
29 */
30
31#include <linux/slab.h>
32#include <linux/export.h>
33#include <linux/bitmap.h>
34#include <linux/rculist.h>
35#include <linux/interrupt.h>
36#include <linux/genalloc.h>
37#include <linux/of_address.h>
38#include <linux/of_device.h>
39
40static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
41{
42 return chunk->end_addr - chunk->start_addr + 1;
43}
44
45static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
46{
47 unsigned long val, nval;
48
49 nval = *addr;
50 do {
51 val = nval;
52 if (val & mask_to_set)
53 return -EBUSY;
54 cpu_relax();
55 } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
56
57 return 0;
58}
59
60static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
61{
62 unsigned long val, nval;
63
64 nval = *addr;
65 do {
66 val = nval;
67 if ((val & mask_to_clear) != mask_to_clear)
68 return -EBUSY;
69 cpu_relax();
70 } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
71
72 return 0;
73}
74
75/*
76 * bitmap_set_ll - set the specified number of bits at the specified position
77 * @map: pointer to a bitmap
78 * @start: a bit position in @map
79 * @nr: number of bits to set
80 *
81 * Set @nr bits start from @start in @map lock-lessly. Several users
82 * can set/clear the same bitmap simultaneously without lock. If two
83 * users set the same bit, one user will return remain bits, otherwise
84 * return 0.
85 */
86static int bitmap_set_ll(unsigned long *map, int start, int nr)
87{
88 unsigned long *p = map + BIT_WORD(start);
89 const int size = start + nr;
90 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
91 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
92
93 while (nr - bits_to_set >= 0) {
94 if (set_bits_ll(p, mask_to_set))
95 return nr;
96 nr -= bits_to_set;
97 bits_to_set = BITS_PER_LONG;
98 mask_to_set = ~0UL;
99 p++;
100 }
101 if (nr) {
102 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
103 if (set_bits_ll(p, mask_to_set))
104 return nr;
105 }
106
107 return 0;
108}
109
110/*
111 * bitmap_clear_ll - clear the specified number of bits at the specified position
112 * @map: pointer to a bitmap
113 * @start: a bit position in @map
114 * @nr: number of bits to set
115 *
116 * Clear @nr bits start from @start in @map lock-lessly. Several users
117 * can set/clear the same bitmap simultaneously without lock. If two
118 * users clear the same bit, one user will return remain bits,
119 * otherwise return 0.
120 */
121static int bitmap_clear_ll(unsigned long *map, int start, int nr)
122{
123 unsigned long *p = map + BIT_WORD(start);
124 const int size = start + nr;
125 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
126 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
127
128 while (nr - bits_to_clear >= 0) {
129 if (clear_bits_ll(p, mask_to_clear))
130 return nr;
131 nr -= bits_to_clear;
132 bits_to_clear = BITS_PER_LONG;
133 mask_to_clear = ~0UL;
134 p++;
135 }
136 if (nr) {
137 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
138 if (clear_bits_ll(p, mask_to_clear))
139 return nr;
140 }
141
142 return 0;
143}
144
145/**
146 * gen_pool_create - create a new special memory pool
147 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
148 * @nid: node id of the node the pool structure should be allocated on, or -1
149 *
150 * Create a new special memory pool that can be used to manage special purpose
151 * memory not managed by the regular kmalloc/kfree interface.
152 */
153struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
154{
155 struct gen_pool *pool;
156
157 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
158 if (pool != NULL) {
159 spin_lock_init(&pool->lock);
160 INIT_LIST_HEAD(&pool->chunks);
161 pool->min_alloc_order = min_alloc_order;
162 pool->algo = gen_pool_first_fit;
163 pool->data = NULL;
164 }
165 return pool;
166}
167EXPORT_SYMBOL(gen_pool_create);
168
169/**
170 * gen_pool_add_virt - add a new chunk of special memory to the pool
171 * @pool: pool to add new memory chunk to
172 * @virt: virtual starting address of memory chunk to add to pool
173 * @phys: physical starting address of memory chunk to add to pool
174 * @size: size in bytes of the memory chunk to add to pool
175 * @nid: node id of the node the chunk structure and bitmap should be
176 * allocated on, or -1
177 *
178 * Add a new chunk of special memory to the specified pool.
179 *
180 * Returns 0 on success or a -ve errno on failure.
181 */
182int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
183 size_t size, int nid)
184{
185 struct gen_pool_chunk *chunk;
186 int nbits = size >> pool->min_alloc_order;
187 int nbytes = sizeof(struct gen_pool_chunk) +
188 BITS_TO_LONGS(nbits) * sizeof(long);
189
190 chunk = kzalloc_node(nbytes, GFP_KERNEL, nid);
191 if (unlikely(chunk == NULL))
192 return -ENOMEM;
193
194 chunk->phys_addr = phys;
195 chunk->start_addr = virt;
196 chunk->end_addr = virt + size - 1;
197 atomic_set(&chunk->avail, size);
198
199 spin_lock(&pool->lock);
200 list_add_rcu(&chunk->next_chunk, &pool->chunks);
201 spin_unlock(&pool->lock);
202
203 return 0;
204}
205EXPORT_SYMBOL(gen_pool_add_virt);
206
207/**
208 * gen_pool_virt_to_phys - return the physical address of memory
209 * @pool: pool to allocate from
210 * @addr: starting address of memory
211 *
212 * Returns the physical address on success, or -1 on error.
213 */
214phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
215{
216 struct gen_pool_chunk *chunk;
217 phys_addr_t paddr = -1;
218
219 rcu_read_lock();
220 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
221 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
222 paddr = chunk->phys_addr + (addr - chunk->start_addr);
223 break;
224 }
225 }
226 rcu_read_unlock();
227
228 return paddr;
229}
230EXPORT_SYMBOL(gen_pool_virt_to_phys);
231
232/**
233 * gen_pool_destroy - destroy a special memory pool
234 * @pool: pool to destroy
235 *
236 * Destroy the specified special memory pool. Verifies that there are no
237 * outstanding allocations.
238 */
239void gen_pool_destroy(struct gen_pool *pool)
240{
241 struct list_head *_chunk, *_next_chunk;
242 struct gen_pool_chunk *chunk;
243 int order = pool->min_alloc_order;
244 int bit, end_bit;
245
246 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
247 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
248 list_del(&chunk->next_chunk);
249
250 end_bit = chunk_size(chunk) >> order;
251 bit = find_next_bit(chunk->bits, end_bit, 0);
252 BUG_ON(bit < end_bit);
253
254 kfree(chunk);
255 }
256 kfree(pool);
257 return;
258}
259EXPORT_SYMBOL(gen_pool_destroy);
260
261/**
262 * gen_pool_alloc - allocate special memory from the pool
263 * @pool: pool to allocate from
264 * @size: number of bytes to allocate from the pool
265 *
266 * Allocate the requested number of bytes from the specified pool.
267 * Uses the pool allocation function (with first-fit algorithm by default).
268 * Can not be used in NMI handler on architectures without
269 * NMI-safe cmpxchg implementation.
270 */
271unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
272{
273 struct gen_pool_chunk *chunk;
274 unsigned long addr = 0;
275 int order = pool->min_alloc_order;
276 int nbits, start_bit = 0, end_bit, remain;
277
278#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
279 BUG_ON(in_nmi());
280#endif
281
282 if (size == 0)
283 return 0;
284
285 nbits = (size + (1UL << order) - 1) >> order;
286 rcu_read_lock();
287 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
288 if (size > atomic_read(&chunk->avail))
289 continue;
290
291 end_bit = chunk_size(chunk) >> order;
292retry:
293 start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits,
294 pool->data);
295 if (start_bit >= end_bit)
296 continue;
297 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
298 if (remain) {
299 remain = bitmap_clear_ll(chunk->bits, start_bit,
300 nbits - remain);
301 BUG_ON(remain);
302 goto retry;
303 }
304
305 addr = chunk->start_addr + ((unsigned long)start_bit << order);
306 size = nbits << order;
307 atomic_sub(size, &chunk->avail);
308 break;
309 }
310 rcu_read_unlock();
311 return addr;
312}
313EXPORT_SYMBOL(gen_pool_alloc);
314
315/**
316 * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
317 * @pool: pool to allocate from
318 * @size: number of bytes to allocate from the pool
319 * @dma: dma-view physical address return value. Use NULL if unneeded.
320 *
321 * Allocate the requested number of bytes from the specified pool.
322 * Uses the pool allocation function (with first-fit algorithm by default).
323 * Can not be used in NMI handler on architectures without
324 * NMI-safe cmpxchg implementation.
325 */
326void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
327{
328 unsigned long vaddr;
329
330 if (!pool)
331 return NULL;
332
333 vaddr = gen_pool_alloc(pool, size);
334 if (!vaddr)
335 return NULL;
336
337 if (dma)
338 *dma = gen_pool_virt_to_phys(pool, vaddr);
339
340 return (void *)vaddr;
341}
342EXPORT_SYMBOL(gen_pool_dma_alloc);
343
344/**
345 * gen_pool_free - free allocated special memory back to the pool
346 * @pool: pool to free to
347 * @addr: starting address of memory to free back to pool
348 * @size: size in bytes of memory to free
349 *
350 * Free previously allocated special memory back to the specified
351 * pool. Can not be used in NMI handler on architectures without
352 * NMI-safe cmpxchg implementation.
353 */
354void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
355{
356 struct gen_pool_chunk *chunk;
357 int order = pool->min_alloc_order;
358 int start_bit, nbits, remain;
359
360#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
361 BUG_ON(in_nmi());
362#endif
363
364 nbits = (size + (1UL << order) - 1) >> order;
365 rcu_read_lock();
366 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
367 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
368 BUG_ON(addr + size - 1 > chunk->end_addr);
369 start_bit = (addr - chunk->start_addr) >> order;
370 remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
371 BUG_ON(remain);
372 size = nbits << order;
373 atomic_add(size, &chunk->avail);
374 rcu_read_unlock();
375 return;
376 }
377 }
378 rcu_read_unlock();
379 BUG();
380}
381EXPORT_SYMBOL(gen_pool_free);
382
383/**
384 * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
385 * @pool: the generic memory pool
386 * @func: func to call
387 * @data: additional data used by @func
388 *
389 * Call @func for every chunk of generic memory pool. The @func is
390 * called with rcu_read_lock held.
391 */
392void gen_pool_for_each_chunk(struct gen_pool *pool,
393 void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
394 void *data)
395{
396 struct gen_pool_chunk *chunk;
397
398 rcu_read_lock();
399 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
400 func(pool, chunk, data);
401 rcu_read_unlock();
402}
403EXPORT_SYMBOL(gen_pool_for_each_chunk);
404
405/**
406 * gen_pool_avail - get available free space of the pool
407 * @pool: pool to get available free space
408 *
409 * Return available free space of the specified pool.
410 */
411size_t gen_pool_avail(struct gen_pool *pool)
412{
413 struct gen_pool_chunk *chunk;
414 size_t avail = 0;
415
416 rcu_read_lock();
417 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
418 avail += atomic_read(&chunk->avail);
419 rcu_read_unlock();
420 return avail;
421}
422EXPORT_SYMBOL_GPL(gen_pool_avail);
423
424/**
425 * gen_pool_size - get size in bytes of memory managed by the pool
426 * @pool: pool to get size
427 *
428 * Return size in bytes of memory managed by the pool.
429 */
430size_t gen_pool_size(struct gen_pool *pool)
431{
432 struct gen_pool_chunk *chunk;
433 size_t size = 0;
434
435 rcu_read_lock();
436 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
437 size += chunk_size(chunk);
438 rcu_read_unlock();
439 return size;
440}
441EXPORT_SYMBOL_GPL(gen_pool_size);
442
443/**
444 * gen_pool_set_algo - set the allocation algorithm
445 * @pool: pool to change allocation algorithm
446 * @algo: custom algorithm function
447 * @data: additional data used by @algo
448 *
449 * Call @algo for each memory allocation in the pool.
450 * If @algo is NULL use gen_pool_first_fit as default
451 * memory allocation function.
452 */
453void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
454{
455 rcu_read_lock();
456
457 pool->algo = algo;
458 if (!pool->algo)
459 pool->algo = gen_pool_first_fit;
460
461 pool->data = data;
462
463 rcu_read_unlock();
464}
465EXPORT_SYMBOL(gen_pool_set_algo);
466
467/**
468 * gen_pool_first_fit - find the first available region
469 * of memory matching the size requirement (no alignment constraint)
470 * @map: The address to base the search on
471 * @size: The bitmap size in bits
472 * @start: The bitnumber to start searching at
473 * @nr: The number of zeroed bits we're looking for
474 * @data: additional data - unused
475 */
476unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
477 unsigned long start, unsigned int nr, void *data)
478{
479 return bitmap_find_next_zero_area(map, size, start, nr, 0);
480}
481EXPORT_SYMBOL(gen_pool_first_fit);
482
483/**
484 * gen_pool_best_fit - find the best fitting region of memory
485 * macthing the size requirement (no alignment constraint)
486 * @map: The address to base the search on
487 * @size: The bitmap size in bits
488 * @start: The bitnumber to start searching at
489 * @nr: The number of zeroed bits we're looking for
490 * @data: additional data - unused
491 *
492 * Iterate over the bitmap to find the smallest free region
493 * which we can allocate the memory.
494 */
495unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
496 unsigned long start, unsigned int nr, void *data)
497{
498 unsigned long start_bit = size;
499 unsigned long len = size + 1;
500 unsigned long index;
501
502 index = bitmap_find_next_zero_area(map, size, start, nr, 0);
503
504 while (index < size) {
505 int next_bit = find_next_bit(map, size, index + nr);
506 if ((next_bit - index) < len) {
507 len = next_bit - index;
508 start_bit = index;
509 if (len == nr)
510 return start_bit;
511 }
512 index = bitmap_find_next_zero_area(map, size,
513 next_bit + 1, nr, 0);
514 }
515
516 return start_bit;
517}
518EXPORT_SYMBOL(gen_pool_best_fit);
519
520static void devm_gen_pool_release(struct device *dev, void *res)
521{
522 gen_pool_destroy(*(struct gen_pool **)res);
523}
524
525/**
526 * devm_gen_pool_create - managed gen_pool_create
527 * @dev: device that provides the gen_pool
528 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
529 * @nid: node id of the node the pool structure should be allocated on, or -1
530 *
531 * Create a new special memory pool that can be used to manage special purpose
532 * memory not managed by the regular kmalloc/kfree interface. The pool will be
533 * automatically destroyed by the device management code.
534 */
535struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
536 int nid)
537{
538 struct gen_pool **ptr, *pool;
539
540 ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
541
542 pool = gen_pool_create(min_alloc_order, nid);
543 if (pool) {
544 *ptr = pool;
545 devres_add(dev, ptr);
546 } else {
547 devres_free(ptr);
548 }
549
550 return pool;
551}
552
553/**
554 * dev_get_gen_pool - Obtain the gen_pool (if any) for a device
555 * @dev: device to retrieve the gen_pool from
556 *
557 * Returns the gen_pool for the device if one is present, or NULL.
558 */
559struct gen_pool *dev_get_gen_pool(struct device *dev)
560{
561 struct gen_pool **p = devres_find(dev, devm_gen_pool_release, NULL,
562 NULL);
563
564 if (!p)
565 return NULL;
566 return *p;
567}
568EXPORT_SYMBOL_GPL(dev_get_gen_pool);
569
570#ifdef CONFIG_OF
571/**
572 * of_get_named_gen_pool - find a pool by phandle property
573 * @np: device node
574 * @propname: property name containing phandle(s)
575 * @index: index into the phandle array
576 *
577 * Returns the pool that contains the chunk starting at the physical
578 * address of the device tree node pointed at by the phandle property,
579 * or NULL if not found.
580 */
581struct gen_pool *of_get_named_gen_pool(struct device_node *np,
582 const char *propname, int index)
583{
584 struct platform_device *pdev;
585 struct device_node *np_pool;
586
587 np_pool = of_parse_phandle(np, propname, index);
588 if (!np_pool)
589 return NULL;
590 pdev = of_find_device_by_node(np_pool);
591 if (!pdev)
592 return NULL;
593 return dev_get_gen_pool(&pdev->dev);
594}
595EXPORT_SYMBOL_GPL(of_get_named_gen_pool);
596#endif /* CONFIG_OF */
1/*
2 * Basic general purpose allocator for managing special purpose
3 * memory, for example, memory that is not managed by the regular
4 * kmalloc/kfree interface. Uses for this includes on-device special
5 * memory, uncached memory etc.
6 *
7 * It is safe to use the allocator in NMI handlers and other special
8 * unblockable contexts that could otherwise deadlock on locks. This
9 * is implemented by using atomic operations and retries on any
10 * conflicts. The disadvantage is that there may be livelocks in
11 * extreme cases. For better scalability, one allocator can be used
12 * for each CPU.
13 *
14 * The lockless operation only works if there is enough memory
15 * available. If new memory is added to the pool a lock has to be
16 * still taken. So any user relying on locklessness has to ensure
17 * that sufficient memory is preallocated.
18 *
19 * The basic atomic operation of this allocator is cmpxchg on long.
20 * On architectures that don't have NMI-safe cmpxchg implementation,
21 * the allocator can NOT be used in NMI handler. So code uses the
22 * allocator in NMI handler should depend on
23 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
24 *
25 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
26 *
27 * This source code is licensed under the GNU General Public License,
28 * Version 2. See the file COPYING for more details.
29 */
30
31#include <linux/slab.h>
32#include <linux/export.h>
33#include <linux/bitmap.h>
34#include <linux/rculist.h>
35#include <linux/interrupt.h>
36#include <linux/genalloc.h>
37
38static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
39{
40 unsigned long val, nval;
41
42 nval = *addr;
43 do {
44 val = nval;
45 if (val & mask_to_set)
46 return -EBUSY;
47 cpu_relax();
48 } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
49
50 return 0;
51}
52
53static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
54{
55 unsigned long val, nval;
56
57 nval = *addr;
58 do {
59 val = nval;
60 if ((val & mask_to_clear) != mask_to_clear)
61 return -EBUSY;
62 cpu_relax();
63 } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
64
65 return 0;
66}
67
68/*
69 * bitmap_set_ll - set the specified number of bits at the specified position
70 * @map: pointer to a bitmap
71 * @start: a bit position in @map
72 * @nr: number of bits to set
73 *
74 * Set @nr bits start from @start in @map lock-lessly. Several users
75 * can set/clear the same bitmap simultaneously without lock. If two
76 * users set the same bit, one user will return remain bits, otherwise
77 * return 0.
78 */
79static int bitmap_set_ll(unsigned long *map, int start, int nr)
80{
81 unsigned long *p = map + BIT_WORD(start);
82 const int size = start + nr;
83 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
84 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
85
86 while (nr - bits_to_set >= 0) {
87 if (set_bits_ll(p, mask_to_set))
88 return nr;
89 nr -= bits_to_set;
90 bits_to_set = BITS_PER_LONG;
91 mask_to_set = ~0UL;
92 p++;
93 }
94 if (nr) {
95 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
96 if (set_bits_ll(p, mask_to_set))
97 return nr;
98 }
99
100 return 0;
101}
102
103/*
104 * bitmap_clear_ll - clear the specified number of bits at the specified position
105 * @map: pointer to a bitmap
106 * @start: a bit position in @map
107 * @nr: number of bits to set
108 *
109 * Clear @nr bits start from @start in @map lock-lessly. Several users
110 * can set/clear the same bitmap simultaneously without lock. If two
111 * users clear the same bit, one user will return remain bits,
112 * otherwise return 0.
113 */
114static int bitmap_clear_ll(unsigned long *map, int start, int nr)
115{
116 unsigned long *p = map + BIT_WORD(start);
117 const int size = start + nr;
118 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
119 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
120
121 while (nr - bits_to_clear >= 0) {
122 if (clear_bits_ll(p, mask_to_clear))
123 return nr;
124 nr -= bits_to_clear;
125 bits_to_clear = BITS_PER_LONG;
126 mask_to_clear = ~0UL;
127 p++;
128 }
129 if (nr) {
130 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
131 if (clear_bits_ll(p, mask_to_clear))
132 return nr;
133 }
134
135 return 0;
136}
137
138/**
139 * gen_pool_create - create a new special memory pool
140 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
141 * @nid: node id of the node the pool structure should be allocated on, or -1
142 *
143 * Create a new special memory pool that can be used to manage special purpose
144 * memory not managed by the regular kmalloc/kfree interface.
145 */
146struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
147{
148 struct gen_pool *pool;
149
150 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
151 if (pool != NULL) {
152 spin_lock_init(&pool->lock);
153 INIT_LIST_HEAD(&pool->chunks);
154 pool->min_alloc_order = min_alloc_order;
155 }
156 return pool;
157}
158EXPORT_SYMBOL(gen_pool_create);
159
160/**
161 * gen_pool_add_virt - add a new chunk of special memory to the pool
162 * @pool: pool to add new memory chunk to
163 * @virt: virtual starting address of memory chunk to add to pool
164 * @phys: physical starting address of memory chunk to add to pool
165 * @size: size in bytes of the memory chunk to add to pool
166 * @nid: node id of the node the chunk structure and bitmap should be
167 * allocated on, or -1
168 *
169 * Add a new chunk of special memory to the specified pool.
170 *
171 * Returns 0 on success or a -ve errno on failure.
172 */
173int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
174 size_t size, int nid)
175{
176 struct gen_pool_chunk *chunk;
177 int nbits = size >> pool->min_alloc_order;
178 int nbytes = sizeof(struct gen_pool_chunk) +
179 (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
180
181 chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
182 if (unlikely(chunk == NULL))
183 return -ENOMEM;
184
185 chunk->phys_addr = phys;
186 chunk->start_addr = virt;
187 chunk->end_addr = virt + size;
188 atomic_set(&chunk->avail, size);
189
190 spin_lock(&pool->lock);
191 list_add_rcu(&chunk->next_chunk, &pool->chunks);
192 spin_unlock(&pool->lock);
193
194 return 0;
195}
196EXPORT_SYMBOL(gen_pool_add_virt);
197
198/**
199 * gen_pool_virt_to_phys - return the physical address of memory
200 * @pool: pool to allocate from
201 * @addr: starting address of memory
202 *
203 * Returns the physical address on success, or -1 on error.
204 */
205phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
206{
207 struct gen_pool_chunk *chunk;
208 phys_addr_t paddr = -1;
209
210 rcu_read_lock();
211 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
212 if (addr >= chunk->start_addr && addr < chunk->end_addr) {
213 paddr = chunk->phys_addr + (addr - chunk->start_addr);
214 break;
215 }
216 }
217 rcu_read_unlock();
218
219 return paddr;
220}
221EXPORT_SYMBOL(gen_pool_virt_to_phys);
222
223/**
224 * gen_pool_destroy - destroy a special memory pool
225 * @pool: pool to destroy
226 *
227 * Destroy the specified special memory pool. Verifies that there are no
228 * outstanding allocations.
229 */
230void gen_pool_destroy(struct gen_pool *pool)
231{
232 struct list_head *_chunk, *_next_chunk;
233 struct gen_pool_chunk *chunk;
234 int order = pool->min_alloc_order;
235 int bit, end_bit;
236
237 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
238 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
239 list_del(&chunk->next_chunk);
240
241 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
242 bit = find_next_bit(chunk->bits, end_bit, 0);
243 BUG_ON(bit < end_bit);
244
245 kfree(chunk);
246 }
247 kfree(pool);
248 return;
249}
250EXPORT_SYMBOL(gen_pool_destroy);
251
252/**
253 * gen_pool_alloc - allocate special memory from the pool
254 * @pool: pool to allocate from
255 * @size: number of bytes to allocate from the pool
256 *
257 * Allocate the requested number of bytes from the specified pool.
258 * Uses a first-fit algorithm. Can not be used in NMI handler on
259 * architectures without NMI-safe cmpxchg implementation.
260 */
261unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
262{
263 struct gen_pool_chunk *chunk;
264 unsigned long addr = 0;
265 int order = pool->min_alloc_order;
266 int nbits, start_bit = 0, end_bit, remain;
267
268#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
269 BUG_ON(in_nmi());
270#endif
271
272 if (size == 0)
273 return 0;
274
275 nbits = (size + (1UL << order) - 1) >> order;
276 rcu_read_lock();
277 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
278 if (size > atomic_read(&chunk->avail))
279 continue;
280
281 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
282retry:
283 start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit,
284 start_bit, nbits, 0);
285 if (start_bit >= end_bit)
286 continue;
287 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
288 if (remain) {
289 remain = bitmap_clear_ll(chunk->bits, start_bit,
290 nbits - remain);
291 BUG_ON(remain);
292 goto retry;
293 }
294
295 addr = chunk->start_addr + ((unsigned long)start_bit << order);
296 size = nbits << order;
297 atomic_sub(size, &chunk->avail);
298 break;
299 }
300 rcu_read_unlock();
301 return addr;
302}
303EXPORT_SYMBOL(gen_pool_alloc);
304
305/**
306 * gen_pool_free - free allocated special memory back to the pool
307 * @pool: pool to free to
308 * @addr: starting address of memory to free back to pool
309 * @size: size in bytes of memory to free
310 *
311 * Free previously allocated special memory back to the specified
312 * pool. Can not be used in NMI handler on architectures without
313 * NMI-safe cmpxchg implementation.
314 */
315void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
316{
317 struct gen_pool_chunk *chunk;
318 int order = pool->min_alloc_order;
319 int start_bit, nbits, remain;
320
321#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
322 BUG_ON(in_nmi());
323#endif
324
325 nbits = (size + (1UL << order) - 1) >> order;
326 rcu_read_lock();
327 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
328 if (addr >= chunk->start_addr && addr < chunk->end_addr) {
329 BUG_ON(addr + size > chunk->end_addr);
330 start_bit = (addr - chunk->start_addr) >> order;
331 remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
332 BUG_ON(remain);
333 size = nbits << order;
334 atomic_add(size, &chunk->avail);
335 rcu_read_unlock();
336 return;
337 }
338 }
339 rcu_read_unlock();
340 BUG();
341}
342EXPORT_SYMBOL(gen_pool_free);
343
344/**
345 * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
346 * @pool: the generic memory pool
347 * @func: func to call
348 * @data: additional data used by @func
349 *
350 * Call @func for every chunk of generic memory pool. The @func is
351 * called with rcu_read_lock held.
352 */
353void gen_pool_for_each_chunk(struct gen_pool *pool,
354 void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
355 void *data)
356{
357 struct gen_pool_chunk *chunk;
358
359 rcu_read_lock();
360 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
361 func(pool, chunk, data);
362 rcu_read_unlock();
363}
364EXPORT_SYMBOL(gen_pool_for_each_chunk);
365
366/**
367 * gen_pool_avail - get available free space of the pool
368 * @pool: pool to get available free space
369 *
370 * Return available free space of the specified pool.
371 */
372size_t gen_pool_avail(struct gen_pool *pool)
373{
374 struct gen_pool_chunk *chunk;
375 size_t avail = 0;
376
377 rcu_read_lock();
378 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
379 avail += atomic_read(&chunk->avail);
380 rcu_read_unlock();
381 return avail;
382}
383EXPORT_SYMBOL_GPL(gen_pool_avail);
384
385/**
386 * gen_pool_size - get size in bytes of memory managed by the pool
387 * @pool: pool to get size
388 *
389 * Return size in bytes of memory managed by the pool.
390 */
391size_t gen_pool_size(struct gen_pool *pool)
392{
393 struct gen_pool_chunk *chunk;
394 size_t size = 0;
395
396 rcu_read_lock();
397 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
398 size += chunk->end_addr - chunk->start_addr;
399 rcu_read_unlock();
400 return size;
401}
402EXPORT_SYMBOL_GPL(gen_pool_size);