blob: ca208a92628c1b49a6f5c1fece1a81592a65ecaa [file] [log] [blame]
Jes Sorensenf14f75b2005-06-21 17:15:02 -07001/*
Huang Ying7f184272011-07-13 13:14:24 +08002 * 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.
Jes Sorensenf14f75b2005-06-21 17:15:02 -070024 *
Jes Sorensenf14f75b2005-06-21 17:15:02 -070025 * 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
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090031#include <linux/slab.h>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -050032#include <linux/export.h>
Akinobu Mita243797f2009-12-15 16:48:31 -080033#include <linux/bitmap.h>
Huang Ying7f184272011-07-13 13:14:24 +080034#include <linux/rculist.h>
35#include <linux/interrupt.h>
Jes Sorensenf14f75b2005-06-21 17:15:02 -070036#include <linux/genalloc.h>
37
Huang Ying7f184272011-07-13 13:14:24 +080038static 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}
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700137
Dean Nelsona58cbd72006-10-02 02:17:01 -0700138/**
139 * gen_pool_create - create a new special memory pool
Dean Nelson929f9722006-06-23 02:03:21 -0700140 * @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
Dean Nelsona58cbd72006-10-02 02:17:01 -0700142 *
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.
Dean Nelson929f9722006-06-23 02:03:21 -0700145 */
146struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700147{
Dean Nelson929f9722006-06-23 02:03:21 -0700148 struct gen_pool *pool;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700149
Dean Nelson929f9722006-06-23 02:03:21 -0700150 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
151 if (pool != NULL) {
Huang Ying7f184272011-07-13 13:14:24 +0800152 spin_lock_init(&pool->lock);
Dean Nelson929f9722006-06-23 02:03:21 -0700153 INIT_LIST_HEAD(&pool->chunks);
154 pool->min_alloc_order = min_alloc_order;
Benjamin Gaignardca279cf2012-10-04 17:13:20 -0700155 pool->algo = gen_pool_first_fit;
156 pool->data = NULL;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700157 }
Dean Nelson929f9722006-06-23 02:03:21 -0700158 return pool;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700159}
160EXPORT_SYMBOL(gen_pool_create);
161
Dean Nelsona58cbd72006-10-02 02:17:01 -0700162/**
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700163 * gen_pool_add_virt - add a new chunk of special memory to the pool
Dean Nelson929f9722006-06-23 02:03:21 -0700164 * @pool: pool to add new memory chunk to
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700165 * @virt: virtual starting address of memory chunk to add to pool
166 * @phys: physical starting address of memory chunk to add to pool
Dean Nelson929f9722006-06-23 02:03:21 -0700167 * @size: size in bytes of the memory chunk to add to pool
168 * @nid: node id of the node the chunk structure and bitmap should be
169 * allocated on, or -1
Dean Nelsona58cbd72006-10-02 02:17:01 -0700170 *
171 * Add a new chunk of special memory to the specified pool.
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700172 *
173 * Returns 0 on success or a -ve errno on failure.
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700174 */
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700175int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
176 size_t size, int nid)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700177{
Dean Nelson929f9722006-06-23 02:03:21 -0700178 struct gen_pool_chunk *chunk;
179 int nbits = size >> pool->min_alloc_order;
180 int nbytes = sizeof(struct gen_pool_chunk) +
181 (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700182
Christoph Lameter94f60302007-07-17 04:03:29 -0700183 chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
Dean Nelson929f9722006-06-23 02:03:21 -0700184 if (unlikely(chunk == NULL))
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700185 return -ENOMEM;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700186
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700187 chunk->phys_addr = phys;
188 chunk->start_addr = virt;
189 chunk->end_addr = virt + size;
Huang Ying7f184272011-07-13 13:14:24 +0800190 atomic_set(&chunk->avail, size);
Dean Nelson929f9722006-06-23 02:03:21 -0700191
Huang Ying7f184272011-07-13 13:14:24 +0800192 spin_lock(&pool->lock);
193 list_add_rcu(&chunk->next_chunk, &pool->chunks);
194 spin_unlock(&pool->lock);
Dean Nelson929f9722006-06-23 02:03:21 -0700195
196 return 0;
197}
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700198EXPORT_SYMBOL(gen_pool_add_virt);
199
200/**
201 * gen_pool_virt_to_phys - return the physical address of memory
202 * @pool: pool to allocate from
203 * @addr: starting address of memory
204 *
205 * Returns the physical address on success, or -1 on error.
206 */
207phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
208{
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700209 struct gen_pool_chunk *chunk;
Huang Ying7f184272011-07-13 13:14:24 +0800210 phys_addr_t paddr = -1;
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700211
Huang Ying7f184272011-07-13 13:14:24 +0800212 rcu_read_lock();
213 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
214 if (addr >= chunk->start_addr && addr < chunk->end_addr) {
215 paddr = chunk->phys_addr + (addr - chunk->start_addr);
216 break;
217 }
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700218 }
Huang Ying7f184272011-07-13 13:14:24 +0800219 rcu_read_unlock();
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700220
Huang Ying7f184272011-07-13 13:14:24 +0800221 return paddr;
Jean-Christophe PLAGNIOL-VILLARD3c8f3702011-05-24 17:13:34 -0700222}
223EXPORT_SYMBOL(gen_pool_virt_to_phys);
Dean Nelson929f9722006-06-23 02:03:21 -0700224
Dean Nelsona58cbd72006-10-02 02:17:01 -0700225/**
226 * gen_pool_destroy - destroy a special memory pool
Steve Wise322acc92006-10-02 02:17:00 -0700227 * @pool: pool to destroy
Dean Nelsona58cbd72006-10-02 02:17:01 -0700228 *
229 * Destroy the specified special memory pool. Verifies that there are no
230 * outstanding allocations.
Steve Wise322acc92006-10-02 02:17:00 -0700231 */
232void gen_pool_destroy(struct gen_pool *pool)
233{
234 struct list_head *_chunk, *_next_chunk;
235 struct gen_pool_chunk *chunk;
236 int order = pool->min_alloc_order;
237 int bit, end_bit;
238
Steve Wise322acc92006-10-02 02:17:00 -0700239 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
240 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
241 list_del(&chunk->next_chunk);
242
243 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
244 bit = find_next_bit(chunk->bits, end_bit, 0);
245 BUG_ON(bit < end_bit);
246
247 kfree(chunk);
248 }
249 kfree(pool);
250 return;
251}
252EXPORT_SYMBOL(gen_pool_destroy);
253
Dean Nelsona58cbd72006-10-02 02:17:01 -0700254/**
255 * gen_pool_alloc - allocate special memory from the pool
Dean Nelson929f9722006-06-23 02:03:21 -0700256 * @pool: pool to allocate from
257 * @size: number of bytes to allocate from the pool
Dean Nelsona58cbd72006-10-02 02:17:01 -0700258 *
259 * Allocate the requested number of bytes from the specified pool.
Benjamin Gaignardca279cf2012-10-04 17:13:20 -0700260 * Uses the pool allocation function (with first-fit algorithm by default).
261 * Can not be used in NMI handler on architectures without
262 * NMI-safe cmpxchg implementation.
Dean Nelson929f9722006-06-23 02:03:21 -0700263 */
264unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
265{
Dean Nelson929f9722006-06-23 02:03:21 -0700266 struct gen_pool_chunk *chunk;
Huang Ying7f184272011-07-13 13:14:24 +0800267 unsigned long addr = 0;
Dean Nelson929f9722006-06-23 02:03:21 -0700268 int order = pool->min_alloc_order;
Huang Ying7f184272011-07-13 13:14:24 +0800269 int nbits, start_bit = 0, end_bit, remain;
270
271#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
272 BUG_ON(in_nmi());
273#endif
Dean Nelson929f9722006-06-23 02:03:21 -0700274
275 if (size == 0)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700276 return 0;
277
Dean Nelson929f9722006-06-23 02:03:21 -0700278 nbits = (size + (1UL << order) - 1) >> order;
Huang Ying7f184272011-07-13 13:14:24 +0800279 rcu_read_lock();
280 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
281 if (size > atomic_read(&chunk->avail))
282 continue;
Dean Nelson929f9722006-06-23 02:03:21 -0700283
284 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
Huang Ying7f184272011-07-13 13:14:24 +0800285retry:
Benjamin Gaignardca279cf2012-10-04 17:13:20 -0700286 start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits,
287 pool->data);
Huang Ying7f184272011-07-13 13:14:24 +0800288 if (start_bit >= end_bit)
Akinobu Mita243797f2009-12-15 16:48:31 -0800289 continue;
Huang Ying7f184272011-07-13 13:14:24 +0800290 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
291 if (remain) {
292 remain = bitmap_clear_ll(chunk->bits, start_bit,
293 nbits - remain);
294 BUG_ON(remain);
295 goto retry;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700296 }
Akinobu Mita243797f2009-12-15 16:48:31 -0800297
298 addr = chunk->start_addr + ((unsigned long)start_bit << order);
Huang Ying7f184272011-07-13 13:14:24 +0800299 size = nbits << order;
300 atomic_sub(size, &chunk->avail);
301 break;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700302 }
Huang Ying7f184272011-07-13 13:14:24 +0800303 rcu_read_unlock();
304 return addr;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700305}
306EXPORT_SYMBOL(gen_pool_alloc);
307
Dean Nelsona58cbd72006-10-02 02:17:01 -0700308/**
309 * gen_pool_free - free allocated special memory back to the pool
Dean Nelson929f9722006-06-23 02:03:21 -0700310 * @pool: pool to free to
311 * @addr: starting address of memory to free back to pool
312 * @size: size in bytes of memory to free
Dean Nelsona58cbd72006-10-02 02:17:01 -0700313 *
Huang Ying7f184272011-07-13 13:14:24 +0800314 * Free previously allocated special memory back to the specified
315 * pool. Can not be used in NMI handler on architectures without
316 * NMI-safe cmpxchg implementation.
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700317 */
Dean Nelson929f9722006-06-23 02:03:21 -0700318void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700319{
Dean Nelson929f9722006-06-23 02:03:21 -0700320 struct gen_pool_chunk *chunk;
Dean Nelson929f9722006-06-23 02:03:21 -0700321 int order = pool->min_alloc_order;
Huang Ying7f184272011-07-13 13:14:24 +0800322 int start_bit, nbits, remain;
323
324#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
325 BUG_ON(in_nmi());
326#endif
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700327
Dean Nelson929f9722006-06-23 02:03:21 -0700328 nbits = (size + (1UL << order) - 1) >> order;
Huang Ying7f184272011-07-13 13:14:24 +0800329 rcu_read_lock();
330 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
Dean Nelson929f9722006-06-23 02:03:21 -0700331 if (addr >= chunk->start_addr && addr < chunk->end_addr) {
332 BUG_ON(addr + size > chunk->end_addr);
Huang Ying7f184272011-07-13 13:14:24 +0800333 start_bit = (addr - chunk->start_addr) >> order;
334 remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
335 BUG_ON(remain);
336 size = nbits << order;
337 atomic_add(size, &chunk->avail);
338 rcu_read_unlock();
339 return;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700340 }
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700341 }
Huang Ying7f184272011-07-13 13:14:24 +0800342 rcu_read_unlock();
343 BUG();
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700344}
345EXPORT_SYMBOL(gen_pool_free);
Huang Ying7f184272011-07-13 13:14:24 +0800346
347/**
348 * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
349 * @pool: the generic memory pool
350 * @func: func to call
351 * @data: additional data used by @func
352 *
353 * Call @func for every chunk of generic memory pool. The @func is
354 * called with rcu_read_lock held.
355 */
356void gen_pool_for_each_chunk(struct gen_pool *pool,
357 void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
358 void *data)
359{
360 struct gen_pool_chunk *chunk;
361
362 rcu_read_lock();
363 list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
364 func(pool, chunk, data);
365 rcu_read_unlock();
366}
367EXPORT_SYMBOL(gen_pool_for_each_chunk);
368
369/**
370 * gen_pool_avail - get available free space of the pool
371 * @pool: pool to get available free space
372 *
373 * Return available free space of the specified pool.
374 */
375size_t gen_pool_avail(struct gen_pool *pool)
376{
377 struct gen_pool_chunk *chunk;
378 size_t avail = 0;
379
380 rcu_read_lock();
381 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
382 avail += atomic_read(&chunk->avail);
383 rcu_read_unlock();
384 return avail;
385}
386EXPORT_SYMBOL_GPL(gen_pool_avail);
387
388/**
389 * gen_pool_size - get size in bytes of memory managed by the pool
390 * @pool: pool to get size
391 *
392 * Return size in bytes of memory managed by the pool.
393 */
394size_t gen_pool_size(struct gen_pool *pool)
395{
396 struct gen_pool_chunk *chunk;
397 size_t size = 0;
398
399 rcu_read_lock();
400 list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
401 size += chunk->end_addr - chunk->start_addr;
402 rcu_read_unlock();
403 return size;
404}
405EXPORT_SYMBOL_GPL(gen_pool_size);
Benjamin Gaignardca279cf2012-10-04 17:13:20 -0700406
407/**
408 * gen_pool_set_algo - set the allocation algorithm
409 * @pool: pool to change allocation algorithm
410 * @algo: custom algorithm function
411 * @data: additional data used by @algo
412 *
413 * Call @algo for each memory allocation in the pool.
414 * If @algo is NULL use gen_pool_first_fit as default
415 * memory allocation function.
416 */
417void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
418{
419 rcu_read_lock();
420
421 pool->algo = algo;
422 if (!pool->algo)
423 pool->algo = gen_pool_first_fit;
424
425 pool->data = data;
426
427 rcu_read_unlock();
428}
429EXPORT_SYMBOL(gen_pool_set_algo);
430
431/**
432 * gen_pool_first_fit - find the first available region
433 * of memory matching the size requirement (no alignment constraint)
434 * @map: The address to base the search on
435 * @size: The bitmap size in bits
436 * @start: The bitnumber to start searching at
437 * @nr: The number of zeroed bits we're looking for
438 * @data: additional data - unused
439 */
440unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
441 unsigned long start, unsigned int nr, void *data)
442{
443 return bitmap_find_next_zero_area(map, size, start, nr, 0);
444}
445EXPORT_SYMBOL(gen_pool_first_fit);
446
447/**
448 * gen_pool_best_fit - find the best fitting region of memory
449 * macthing the size requirement (no alignment constraint)
450 * @map: The address to base the search on
451 * @size: The bitmap size in bits
452 * @start: The bitnumber to start searching at
453 * @nr: The number of zeroed bits we're looking for
454 * @data: additional data - unused
455 *
456 * Iterate over the bitmap to find the smallest free region
457 * which we can allocate the memory.
458 */
459unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
460 unsigned long start, unsigned int nr, void *data)
461{
462 unsigned long start_bit = size;
463 unsigned long len = size + 1;
464 unsigned long index;
465
466 index = bitmap_find_next_zero_area(map, size, start, nr, 0);
467
468 while (index < size) {
469 int next_bit = find_next_bit(map, size, index + nr);
470 if ((next_bit - index) < len) {
471 len = next_bit - index;
472 start_bit = index;
473 if (len == nr)
474 return start_bit;
475 }
476 index = bitmap_find_next_zero_area(map, size,
477 next_bit + 1, nr, 0);
478 }
479
480 return start_bit;
481}
482EXPORT_SYMBOL(gen_pool_best_fit);