| Nicholas Flintham | 1e3d311 | 2013-04-10 10:48:38 +0100 | [diff] [blame^] | 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 | * This source code is licensed under the GNU General Public License, |
| 26 | * Version 2. See the file COPYING for more details. |
| 27 | */ |
| 28 | |
| 29 | |
| 30 | #ifndef __GENALLOC_H__ |
| 31 | #define __GENALLOC_H__ |
| 32 | struct gen_pool { |
| 33 | spinlock_t lock; |
| 34 | struct list_head chunks; |
| 35 | int min_alloc_order; |
| 36 | }; |
| 37 | |
| 38 | struct gen_pool_chunk { |
| 39 | struct list_head next_chunk; |
| 40 | atomic_t avail; |
| 41 | phys_addr_t phys_addr; |
| 42 | unsigned long start_addr; |
| 43 | unsigned long end_addr; |
| 44 | unsigned long bits[0]; |
| 45 | }; |
| 46 | |
| 47 | extern struct gen_pool *gen_pool_create(int, int); |
| 48 | extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); |
| 49 | extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, |
| 50 | size_t, int); |
| 51 | static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, |
| 52 | size_t size, int nid) |
| 53 | { |
| 54 | return gen_pool_add_virt(pool, addr, -1, size, nid); |
| 55 | } |
| 56 | extern void gen_pool_destroy(struct gen_pool *); |
| 57 | extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); |
| 58 | extern void gen_pool_for_each_chunk(struct gen_pool *, |
| 59 | void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); |
| 60 | extern size_t gen_pool_avail(struct gen_pool *); |
| 61 | extern size_t gen_pool_size(struct gen_pool *); |
| 62 | |
| 63 | unsigned long __must_check |
| 64 | gen_pool_alloc_aligned(struct gen_pool *pool, size_t size, |
| 65 | unsigned alignment_order); |
| 66 | |
| 67 | static inline unsigned long __must_check |
| 68 | gen_pool_alloc(struct gen_pool *pool, size_t size) |
| 69 | { |
| 70 | return gen_pool_alloc_aligned(pool, size, 0); |
| 71 | } |
| 72 | |
| 73 | #endif |