lib/genalloc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Basic general purpose allocator for managing special purpose
   4  * memory, for example, memory that is not managed by the regular
   5  * kmalloc/kfree interface.  Uses for this includes on-device special
   6  * memory, uncached memory etc.
   7  *
   8  * It is safe to use the allocator in NMI handlers and other special
   9  * unblockable contexts that could otherwise deadlock on locks.  This
  10  * is implemented by using atomic operations and retries on any
  11  * conflicts.  The disadvantage is that there may be livelocks in
  12  * extreme cases.  For better scalability, one allocator can be used
  13  * for each CPU.
  14  *
  15  * The lockless operation only works if there is enough memory
  16  * available.  If new memory is added to the pool a lock has to be
  17  * still taken.  So any user relying on locklessness has to ensure
  18  * that sufficient memory is preallocated.
  19  *
  20  * The basic atomic operation of this allocator is cmpxchg on long.
  21  * On architectures that don't have NMI-safe cmpxchg implementation,
  22  * the allocator can NOT be used in NMI handler.  So code uses the
  23  * allocator in NMI handler should depend on
  24  * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
  25  *
  26  * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
  27  */
  28
  29 #include <linux/slab.h>
  30 #include <linux/export.h>
  31 #include <linux/bitmap.h>
  32 #include <linux/rculist.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/genalloc.h>
  35 #include <linux/of.h>
  36 #include <linux/of_platform.h>
  37 #include <linux/platform_device.h>
  38 #include <linux/vmalloc.h>
  39
  40 static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
  41 {
  42         return chunk->end_addr - chunk->start_addr + 1;
  43 }
  44
  45 static inline int
  46 set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
  47 {
  48         unsigned long val = READ_ONCE(*addr);
  49
  50         do {
  51                 if (val & mask_to_set)
  52                         return -EBUSY;
  53                 cpu_relax();
  54         } while (!try_cmpxchg(addr, &val, val | mask_to_set));
  55
  56         return 0;
  57 }
  58
  59 static inline int
  60 clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
  61 {
  62         unsigned long val = READ_ONCE(*addr);
  63
  64         do {
  65                 if ((val & mask_to_clear) != mask_to_clear)
  66                         return -EBUSY;
  67                 cpu_relax();
  68         } while (!try_cmpxchg(addr, &val, val & ~mask_to_clear));
  69
  70         return 0;
  71 }
  72
  73 /*
  74  * bitmap_set_ll - set the specified number of bits at the specified position
  75  * @map: pointer to a bitmap
  76  * @start: a bit position in @map
  77  * @nr: number of bits to set
  78  *
  79  * Set @nr bits start from @start in @map lock-lessly. Several users
  80  * can set/clear the same bitmap simultaneously without lock. If two
  81  * users set the same bit, one user will return remain bits, otherwise
  82  * return 0.
  83  */
  84 static unsigned long
  85 bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
  86 {
  87         unsigned long *p = map + BIT_WORD(start);
  88         const unsigned long size = start + nr;
  89         int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
  90         unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
  91
  92         while (nr >= bits_to_set) {
  93                 if (set_bits_ll(p, mask_to_set))
  94                         return nr;
  95                 nr -= bits_to_set;
  96                 bits_to_set = BITS_PER_LONG;
  97                 mask_to_set = ~0UL;
  98                 p++;
  99         }
 100         if (nr) {
 101                 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
 102                 if (set_bits_ll(p, mask_to_set))
 103                         return nr;
 104         }
 105
 106         return 0;
 107 }
 108
 109 /*
 110  * bitmap_clear_ll - clear the specified number of bits at the specified position
 111  * @map: pointer to a bitmap
 112  * @start: a bit position in @map
 113  * @nr: number of bits to set
 114  *
 115  * Clear @nr bits start from @start in @map lock-lessly. Several users
 116  * can set/clear the same bitmap simultaneously without lock. If two
 117  * users clear the same bit, one user will return remain bits,
 118  * otherwise return 0.
 119  */
 120 static unsigned long
 121 bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
 122 {
 123         unsigned long *p = map + BIT_WORD(start);
 124         const unsigned long 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) {
 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  */
 153 struct 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                 pool->name = NULL;
 165         }
 166         return pool;
 167 }
 168 EXPORT_SYMBOL(gen_pool_create);
 169
 170 /**
 171  * gen_pool_add_owner- add a new chunk of special memory to the pool
 172  * @pool: pool to add new memory chunk to
 173  * @virt: virtual starting address of memory chunk to add to pool
 174  * @phys: physical starting address of memory chunk to add to pool
 175  * @size: size in bytes of the memory chunk to add to pool
 176  * @nid: node id of the node the chunk structure and bitmap should be
 177  *       allocated on, or -1
 178  * @owner: private data the publisher would like to recall at alloc time
 179  *
 180  * Add a new chunk of special memory to the specified pool.
 181  *
 182  * Returns 0 on success or a -ve errno on failure.
 183  */
 184 int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
 185                  size_t size, int nid, void *owner)
 186 {
 187         struct gen_pool_chunk *chunk;
 188         unsigned long nbits = size >> pool->min_alloc_order;
 189         unsigned long nbytes = sizeof(struct gen_pool_chunk) +
 190                                 BITS_TO_LONGS(nbits) * sizeof(long);
 191
 192         chunk = vzalloc_node(nbytes, nid);
 193         if (unlikely(chunk == NULL))
 194                 return -ENOMEM;
 195
 196         chunk->phys_addr = phys;
 197         chunk->start_addr = virt;
 198         chunk->end_addr = virt + size - 1;
 199         chunk->owner = owner;
 200         atomic_long_set(&chunk->avail, size);
 201
 202         spin_lock(&pool->lock);
 203         list_add_rcu(&chunk->next_chunk, &pool->chunks);
 204         spin_unlock(&pool->lock);
 205
 206         return 0;
 207 }
 208 EXPORT_SYMBOL(gen_pool_add_owner);
 209
 210 /**
 211  * gen_pool_virt_to_phys - return the physical address of memory
 212  * @pool: pool to allocate from
 213  * @addr: starting address of memory
 214  *
 215  * Returns the physical address on success, or -1 on error.
 216  */
 217 phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
 218 {
 219         struct gen_pool_chunk *chunk;
 220         phys_addr_t paddr = -1;
 221
 222         rcu_read_lock();
 223         list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
 224                 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
 225                         paddr = chunk->phys_addr + (addr - chunk->start_addr);
 226                         break;
 227                 }
 228         }
 229         rcu_read_unlock();
 230
 231         return paddr;
 232 }
 233 EXPORT_SYMBOL(gen_pool_virt_to_phys);
 234
 235 /**
 236  * gen_pool_destroy - destroy a special memory pool
 237  * @pool: pool to destroy
 238  *
 239  * Destroy the specified special memory pool. Verifies that there are no
 240  * outstanding allocations.
 241  */
 242 void gen_pool_destroy(struct gen_pool *pool)
 243 {
 244         struct list_head *_chunk, *_next_chunk;
 245         struct gen_pool_chunk *chunk;
 246         int order = pool->min_alloc_order;
 247         unsigned long bit, end_bit;
 248
 249         list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
 250                 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
 251                 list_del(&chunk->next_chunk);
 252
 253                 end_bit = chunk_size(chunk) >> order;
 254                 bit = find_first_bit(chunk->bits, end_bit);
 255                 BUG_ON(bit < end_bit);
 256
 257                 vfree(chunk);
 258         }
 259         kfree_const(pool->name);
 260         kfree(pool);
 261 }
 262 EXPORT_SYMBOL(gen_pool_destroy);
 263
 264 /**
 265  * gen_pool_alloc_algo_owner - allocate special memory from the pool
 266  * @pool: pool to allocate from
 267  * @size: number of bytes to allocate from the pool
 268  * @algo: algorithm passed from caller
 269  * @data: data passed to algorithm
 270  * @owner: optionally retrieve the chunk owner
 271  *
 272  * Allocate the requested number of bytes from the specified pool.
 273  * Uses the pool allocation function (with first-fit algorithm by default).
 274  * Can not be used in NMI handler on architectures without
 275  * NMI-safe cmpxchg implementation.
 276  */
 277 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
 278                 genpool_algo_t algo, void *data, void **owner)
 279 {
 280         struct gen_pool_chunk *chunk;
 281         unsigned long addr = 0;
 282         int order = pool->min_alloc_order;
 283         unsigned long nbits, start_bit, end_bit, remain;
 284
 285 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
 286         BUG_ON(in_nmi());
 287 #endif
 288
 289         if (owner)
 290                 *owner = NULL;
 291
 292         if (size == 0)
 293                 return 0;
 294
 295         nbits = (size + (1UL << order) - 1) >> order;
 296         rcu_read_lock();
 297         list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
 298                 if (size > atomic_long_read(&chunk->avail))
 299                         continue;
 300
 301                 start_bit = 0;
 302                 end_bit = chunk_size(chunk) >> order;
 303 retry:
 304                 start_bit = algo(chunk->bits, end_bit, start_bit,
 305                                  nbits, data, pool, chunk->start_addr);
 306                 if (start_bit >= end_bit)
 307                         continue;
 308                 remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
 309                 if (remain) {
 310                         remain = bitmap_clear_ll(chunk->bits, start_bit,
 311                                                  nbits - remain);
 312                         BUG_ON(remain);
 313                         goto retry;
 314                 }
 315
 316                 addr = chunk->start_addr + ((unsigned long)start_bit << order);
 317                 size = nbits << order;
 318                 atomic_long_sub(size, &chunk->avail);
 319                 if (owner)
 320                         *owner = chunk->owner;
 321                 break;
 322         }
 323         rcu_read_unlock();
 324         return addr;
 325 }
 326 EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
 327
 328 /**
 329  * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
 330  * @pool: pool to allocate from
 331  * @size: number of bytes to allocate from the pool
 332  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
 333  *
 334  * Allocate the requested number of bytes from the specified pool.
 335  * Uses the pool allocation function (with first-fit algorithm by default).
 336  * Can not be used in NMI handler on architectures without
 337  * NMI-safe cmpxchg implementation.
 338  *
 339  * Return: virtual address of the allocated memory, or %NULL on failure
 340  */
 341 void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
 342 {
 343         return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data);
 344 }
 345 EXPORT_SYMBOL(gen_pool_dma_alloc);
 346
 347 /**
 348  * gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA
 349  * usage with the given pool algorithm
 350  * @pool: pool to allocate from
 351  * @size: number of bytes to allocate from the pool
 352  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
 353  * @algo: algorithm passed from caller
 354  * @data: data passed to algorithm
 355  *
 356  * Allocate the requested number of bytes from the specified pool. Uses the
 357  * given pool allocation function. Can not be used in NMI handler on
 358  * architectures without NMI-safe cmpxchg implementation.
 359  *
 360  * Return: virtual address of the allocated memory, or %NULL on failure
 361  */
 362 void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
 363                 dma_addr_t *dma, genpool_algo_t algo, void *data)
 364 {
 365         unsigned long vaddr;
 366
 367         if (!pool)
 368                 return NULL;
 369
 370         vaddr = gen_pool_alloc_algo(pool, size, algo, data);
 371         if (!vaddr)
 372                 return NULL;
 373
 374         if (dma)
 375                 *dma = gen_pool_virt_to_phys(pool, vaddr);
 376
 377         return (void *)vaddr;
 378 }
 379 EXPORT_SYMBOL(gen_pool_dma_alloc_algo);
 380
 381 /**
 382  * gen_pool_dma_alloc_align - allocate special memory from the pool for DMA
 383  * usage with the given alignment
 384  * @pool: pool to allocate from
 385  * @size: number of bytes to allocate from the pool
 386  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
 387  * @align: alignment in bytes for starting address
 388  *
 389  * Allocate the requested number bytes from the specified pool, with the given
 390  * alignment restriction. Can not be used in NMI handler on architectures
 391  * without NMI-safe cmpxchg implementation.
 392  *
 393  * Return: virtual address of the allocated memory, or %NULL on failure
 394  */
 395 void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
 396                 dma_addr_t *dma, int align)
 397 {
 398         struct genpool_data_align data = { .align = align };
 399
 400         return gen_pool_dma_alloc_algo(pool, size, dma,
 401                         gen_pool_first_fit_align, &data);
 402 }
 403 EXPORT_SYMBOL(gen_pool_dma_alloc_align);
 404
 405 /**
 406  * gen_pool_dma_zalloc - allocate special zeroed memory from the pool for
 407  * DMA usage
 408  * @pool: pool to allocate from
 409  * @size: number of bytes to allocate from the pool
 410  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
 411  *
 412  * Allocate the requested number of zeroed bytes from the specified pool.
 413  * Uses the pool allocation function (with first-fit algorithm by default).
 414  * Can not be used in NMI handler on architectures without
 415  * NMI-safe cmpxchg implementation.
 416  *
 417  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
 418  */
 419 void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
 420 {
 421         return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data);
 422 }
 423 EXPORT_SYMBOL(gen_pool_dma_zalloc);
 424
 425 /**
 426  * gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for
 427  * DMA usage with the given pool algorithm
 428  * @pool: pool to allocate from
 429  * @size: number of bytes to allocate from the pool
 430  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
 431  * @algo: algorithm passed from caller
 432  * @data: data passed to algorithm
 433  *
 434  * Allocate the requested number of zeroed bytes from the specified pool. Uses
 435  * the given pool allocation function. Can not be used in NMI handler on
 436  * architectures without NMI-safe cmpxchg implementation.
 437  *
 438  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
 439  */
 440 void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
 441                 dma_addr_t *dma, genpool_algo_t algo, void *data)
 442 {
 443         void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data);
 444
 445         if (vaddr)
 446                 memset(vaddr, 0, size);
 447
 448         return vaddr;
 449 }
 450 EXPORT_SYMBOL(gen_pool_dma_zalloc_algo);
 451
 452 /**
 453  * gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for
 454  * DMA usage with the given alignment
 455  * @pool: pool to allocate from
 456  * @size: number of bytes to allocate from the pool
 457  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
 458  * @align: alignment in bytes for starting address
 459  *
 460  * Allocate the requested number of zeroed bytes from the specified pool,
 461  * with the given alignment restriction. Can not be used in NMI handler on
 462  * architectures without NMI-safe cmpxchg implementation.
 463  *
 464  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
 465  */
 466 void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
 467                 dma_addr_t *dma, int align)
 468 {
 469         struct genpool_data_align data = { .align = align };
 470
 471         return gen_pool_dma_zalloc_algo(pool, size, dma,
 472                         gen_pool_first_fit_align, &data);
 473 }
 474 EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
 475
 476 /**
 477  * gen_pool_free_owner - free allocated special memory back to the pool
 478  * @pool: pool to free to
 479  * @addr: starting address of memory to free back to pool
 480  * @size: size in bytes of memory to free
 481  * @owner: private data stashed at gen_pool_add() time
 482  *
 483  * Free previously allocated special memory back to the specified
 484  * pool.  Can not be used in NMI handler on architectures without
 485  * NMI-safe cmpxchg implementation.
 486  */
 487 void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
 488                 void **owner)
 489 {
 490         struct gen_pool_chunk *chunk;
 491         int order = pool->min_alloc_order;
 492         unsigned long start_bit, nbits, remain;
 493
 494 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
 495         BUG_ON(in_nmi());
 496 #endif
 497
 498         if (owner)
 499                 *owner = NULL;
 500
 501         nbits = (size + (1UL << order) - 1) >> order;
 502         rcu_read_lock();
 503         list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
 504                 if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
 505                         BUG_ON(addr + size - 1 > chunk->end_addr);
 506                         start_bit = (addr - chunk->start_addr) >> order;
 507                         remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
 508                         BUG_ON(remain);
 509                         size = nbits << order;
 510                         atomic_long_add(size, &chunk->avail);
 511                         if (owner)
 512                                 *owner = chunk->owner;
 513                         rcu_read_unlock();
 514                         return;
 515                 }
 516         }
 517         rcu_read_unlock();
 518         BUG();
 519 }
 520 EXPORT_SYMBOL(gen_pool_free_owner);
 521
 522 /**
 523  * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
 524  * @pool:       the generic memory pool
 525  * @func:       func to call
 526  * @data:       additional data used by @func
 527  *
 528  * Call @func for every chunk of generic memory pool.  The @func is
 529  * called with rcu_read_lock held.
 530  */
 531 void gen_pool_for_each_chunk(struct gen_pool *pool,
 532         void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
 533         void *data)
 534 {
 535         struct gen_pool_chunk *chunk;
 536
 537         rcu_read_lock();
 538         list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
 539                 func(pool, chunk, data);
 540         rcu_read_unlock();
 541 }
 542 EXPORT_SYMBOL(gen_pool_for_each_chunk);
 543
 544 /**
 545  * gen_pool_has_addr - checks if an address falls within the range of a pool
 546  * @pool:       the generic memory pool
 547  * @start:      start address
 548  * @size:       size of the region
 549  *
 550  * Check if the range of addresses falls within the specified pool. Returns
 551  * true if the entire range is contained in the pool and false otherwise.
 552  */
 553 bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
 554                         size_t size)
 555 {
 556         bool found = false;
 557         unsigned long end = start + size - 1;
 558         struct gen_pool_chunk *chunk;
 559
 560         rcu_read_lock();
 561         list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
 562                 if (start >= chunk->start_addr && start <= chunk->end_addr) {
 563                         if (end <= chunk->end_addr) {
 564                                 found = true;
 565                                 break;
 566                         }
 567                 }
 568         }
 569         rcu_read_unlock();
 570         return found;
 571 }
 572 EXPORT_SYMBOL(gen_pool_has_addr);
 573
 574 /**
 575  * gen_pool_avail - get available free space of the pool
 576  * @pool: pool to get available free space
 577  *
 578  * Return available free space of the specified pool.
 579  */
 580 size_t gen_pool_avail(struct gen_pool *pool)
 581 {
 582         struct gen_pool_chunk *chunk;
 583         size_t avail = 0;
 584
 585         rcu_read_lock();
 586         list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
 587                 avail += atomic_long_read(&chunk->avail);
 588         rcu_read_unlock();
 589         return avail;
 590 }
 591 EXPORT_SYMBOL_GPL(gen_pool_avail);
 592
 593 /**
 594  * gen_pool_size - get size in bytes of memory managed by the pool
 595  * @pool: pool to get size
 596  *
 597  * Return size in bytes of memory managed by the pool.
 598  */
 599 size_t gen_pool_size(struct gen_pool *pool)
 600 {
 601         struct gen_pool_chunk *chunk;
 602         size_t size = 0;
 603
 604         rcu_read_lock();
 605         list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
 606                 size += chunk_size(chunk);
 607         rcu_read_unlock();
 608         return size;
 609 }
 610 EXPORT_SYMBOL_GPL(gen_pool_size);
 611
 612 /**
 613  * gen_pool_set_algo - set the allocation algorithm
 614  * @pool: pool to change allocation algorithm
 615  * @algo: custom algorithm function
 616  * @data: additional data used by @algo
 617  *
 618  * Call @algo for each memory allocation in the pool.
 619  * If @algo is NULL use gen_pool_first_fit as default
 620  * memory allocation function.
 621  */
 622 void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
 623 {
 624         rcu_read_lock();
 625
 626         pool->algo = algo;
 627         if (!pool->algo)
 628                 pool->algo = gen_pool_first_fit;
 629
 630         pool->data = data;
 631
 632         rcu_read_unlock();
 633 }
 634 EXPORT_SYMBOL(gen_pool_set_algo);
 635
 636 /**
 637  * gen_pool_first_fit - find the first available region
 638  * of memory matching the size requirement (no alignment constraint)
 639  * @map: The address to base the search on
 640  * @size: The bitmap size in bits
 641  * @start: The bitnumber to start searching at
 642  * @nr: The number of zeroed bits we're looking for
 643  * @data: additional data - unused
 644  * @pool: pool to find the fit region memory from
 645  * @start_addr: not used in this function
 646  */
 647 unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
 648                 unsigned long start, unsigned int nr, void *data,
 649                 struct gen_pool *pool, unsigned long start_addr)
 650 {
 651         return bitmap_find_next_zero_area(map, size, start, nr, 0);
 652 }
 653 EXPORT_SYMBOL(gen_pool_first_fit);
 654
 655 /**
 656  * gen_pool_first_fit_align - find the first available region
 657  * of memory matching the size requirement (alignment constraint)
 658  * @map: The address to base the search on
 659  * @size: The bitmap size in bits
 660  * @start: The bitnumber to start searching at
 661  * @nr: The number of zeroed bits we're looking for
 662  * @data: data for alignment
 663  * @pool: pool to get order from
 664  * @start_addr: start addr of alloction chunk
 665  */
 666 unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
 667                 unsigned long start, unsigned int nr, void *data,
 668                 struct gen_pool *pool, unsigned long start_addr)
 669 {
 670         struct genpool_data_align *alignment;
 671         unsigned long align_mask, align_off;
 672         int order;
 673
 674         alignment = data;
 675         order = pool->min_alloc_order;
 676         align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
 677         align_off = (start_addr & (alignment->align - 1)) >> order;
 678
 679         return bitmap_find_next_zero_area_off(map, size, start, nr,
 680                                               align_mask, align_off);
 681 }
 682 EXPORT_SYMBOL(gen_pool_first_fit_align);
 683
 684 /**
 685  * gen_pool_fixed_alloc - reserve a specific region
 686  * @map: The address to base the search on
 687  * @size: The bitmap size in bits
 688  * @start: The bitnumber to start searching at
 689  * @nr: The number of zeroed bits we're looking for
 690  * @data: data for alignment
 691  * @pool: pool to get order from
 692  * @start_addr: not used in this function
 693  */
 694 unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
 695                 unsigned long start, unsigned int nr, void *data,
 696                 struct gen_pool *pool, unsigned long start_addr)
 697 {
 698         struct genpool_data_fixed *fixed_data;
 699         int order;
 700         unsigned long offset_bit;
 701         unsigned long start_bit;
 702
 703         fixed_data = data;
 704         order = pool->min_alloc_order;
 705         offset_bit = fixed_data->offset >> order;
 706         if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
 707                 return size;
 708
 709         start_bit = bitmap_find_next_zero_area(map, size,
 710                         start + offset_bit, nr, 0);
 711         if (start_bit != offset_bit)
 712                 start_bit = size;
 713         return start_bit;
 714 }
 715 EXPORT_SYMBOL(gen_pool_fixed_alloc);
 716
 717 /**
 718  * gen_pool_first_fit_order_align - find the first available region
 719  * of memory matching the size requirement. The region will be aligned
 720  * to the order of the size specified.
 721  * @map: The address to base the search on
 722  * @size: The bitmap size in bits
 723  * @start: The bitnumber to start searching at
 724  * @nr: The number of zeroed bits we're looking for
 725  * @data: additional data - unused
 726  * @pool: pool to find the fit region memory from
 727  * @start_addr: not used in this function
 728  */
 729 unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 730                 unsigned long size, unsigned long start,
 731                 unsigned int nr, void *data, struct gen_pool *pool,
 732                 unsigned long start_addr)
 733 {
 734         unsigned long align_mask = roundup_pow_of_two(nr) - 1;
 735
 736         return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
 737 }
 738 EXPORT_SYMBOL(gen_pool_first_fit_order_align);
 739
 740 /**
 741  * gen_pool_best_fit - find the best fitting region of memory
 742  * matching the size requirement (no alignment constraint)
 743  * @map: The address to base the search on
 744  * @size: The bitmap size in bits
 745  * @start: The bitnumber to start searching at
 746  * @nr: The number of zeroed bits we're looking for
 747  * @data: additional data - unused
 748  * @pool: pool to find the fit region memory from
 749  * @start_addr: not used in this function
 750  *
 751  * Iterate over the bitmap to find the smallest free region
 752  * which we can allocate the memory.
 753  */
 754 unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 755                 unsigned long start, unsigned int nr, void *data,
 756                 struct gen_pool *pool, unsigned long start_addr)
 757 {
 758         unsigned long start_bit = size;
 759         unsigned long len = size + 1;
 760         unsigned long index;
 761
 762         index = bitmap_find_next_zero_area(map, size, start, nr, 0);
 763
 764         while (index < size) {
 765                 unsigned long next_bit = find_next_bit(map, size, index + nr);
 766                 if ((next_bit - index) < len) {
 767                         len = next_bit - index;
 768                         start_bit = index;
 769                         if (len == nr)
 770                                 return start_bit;
 771                 }
 772                 index = bitmap_find_next_zero_area(map, size,
 773                                                    next_bit + 1, nr, 0);
 774         }
 775
 776         return start_bit;
 777 }
 778 EXPORT_SYMBOL(gen_pool_best_fit);
 779
 780 static void devm_gen_pool_release(struct device *dev, void *res)
 781 {
 782         gen_pool_destroy(*(struct gen_pool **)res);
 783 }
 784
 785 static int devm_gen_pool_match(struct device *dev, void *res, void *data)
 786 {
 787         struct gen_pool **p = res;
 788
 789         /* NULL data matches only a pool without an assigned name */
 790         if (!data && !(*p)->name)
 791                 return 1;
 792
 793         if (!data || !(*p)->name)
 794                 return 0;
 795
 796         return !strcmp((*p)->name, data);
 797 }
 798
 799 /**
 800  * gen_pool_get - Obtain the gen_pool (if any) for a device
 801  * @dev: device to retrieve the gen_pool from
 802  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
 803  *
 804  * Returns the gen_pool for the device if one is present, or NULL.
 805  */
 806 struct gen_pool *gen_pool_get(struct device *dev, const char *name)
 807 {
 808         struct gen_pool **p;
 809
 810         p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
 811                         (void *)name);
 812         if (!p)
 813                 return NULL;
 814         return *p;
 815 }
 816 EXPORT_SYMBOL_GPL(gen_pool_get);
 817
 818 /**
 819  * devm_gen_pool_create - managed gen_pool_create
 820  * @dev: device that provides the gen_pool
 821  * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
 822  * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
 823  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
 824  *
 825  * Create a new special memory pool that can be used to manage special purpose
 826  * memory not managed by the regular kmalloc/kfree interface. The pool will be
 827  * automatically destroyed by the device management code.
 828  */
 829 struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
 830                                       int nid, const char *name)
 831 {
 832         struct gen_pool **ptr, *pool;
 833         const char *pool_name = NULL;
 834
 835         /* Check that genpool to be created is uniquely addressed on device */
 836         if (gen_pool_get(dev, name))
 837                 return ERR_PTR(-EINVAL);
 838
 839         if (name) {
 840                 pool_name = kstrdup_const(name, GFP_KERNEL);
 841                 if (!pool_name)
 842                         return ERR_PTR(-ENOMEM);
 843         }
 844
 845         ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
 846         if (!ptr)
 847                 goto free_pool_name;
 848
 849         pool = gen_pool_create(min_alloc_order, nid);
 850         if (!pool)
 851                 goto free_devres;
 852
 853         *ptr = pool;
 854         pool->name = pool_name;
 855         devres_add(dev, ptr);
 856
 857         return pool;
 858
 859 free_devres:
 860         devres_free(ptr);
 861 free_pool_name:
 862         kfree_const(pool_name);
 863
 864         return ERR_PTR(-ENOMEM);
 865 }
 866 EXPORT_SYMBOL(devm_gen_pool_create);
 867
 868 #ifdef CONFIG_OF
 869 /**
 870  * of_gen_pool_get - find a pool by phandle property
 871  * @np: device node
 872  * @propname: property name containing phandle(s)
 873  * @index: index into the phandle array
 874  *
 875  * Returns the pool that contains the chunk starting at the physical
 876  * address of the device tree node pointed at by the phandle property,
 877  * or NULL if not found.
 878  */
 879 struct gen_pool *of_gen_pool_get(struct device_node *np,
 880         const char *propname, int index)
 881 {
 882         struct platform_device *pdev;
 883         struct device_node *np_pool, *parent;
 884         const char *name = NULL;
 885         struct gen_pool *pool = NULL;
 886
 887         np_pool = of_parse_phandle(np, propname, index);
 888         if (!np_pool)
 889                 return NULL;
 890
 891         pdev = of_find_device_by_node(np_pool);
 892         if (!pdev) {
 893                 /* Check if named gen_pool is created by parent node device */
 894                 parent = of_get_parent(np_pool);
 895                 pdev = of_find_device_by_node(parent);
 896                 of_node_put(parent);
 897
 898                 of_property_read_string(np_pool, "label", &name);
 899                 if (!name)
 900                         name = of_node_full_name(np_pool);
 901         }
 902         if (pdev)
 903                 pool = gen_pool_get(&pdev->dev, name);
 904         of_node_put(np_pool);
 905
 906         return pool;
 907 }
 908 EXPORT_SYMBOL_GPL(of_gen_pool_get);
 909 #endif /* CONFIG_OF */