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 /** 33 * Allocation callback function type definition 34 * @map: Pointer to bitmap 35 * @size: The bitmap size in bits 36 * @start: The bitnumber to start searching at 37 * @nr: The number of zeroed bits we're looking for 38 * @data: optional additional data used by @genpool_algo_t 39 */ 40 typedef unsigned long (*genpool_algo_t)(unsigned long *map, 41 unsigned long size, 42 unsigned long start, 43 unsigned int nr, 44 void *data); 45 46 /* 47 * General purpose special memory pool descriptor. 48 */ 49 struct gen_pool { 50 spinlock_t lock; 51 struct list_head chunks; /* list of chunks in this pool */ 52 int min_alloc_order; /* minimum allocation order */ 53 54 genpool_algo_t algo; /* allocation function */ 55 void *data; 56 }; 57 58 /* 59 * General purpose special memory pool chunk descriptor. 60 */ 61 struct gen_pool_chunk { 62 struct list_head next_chunk; /* next chunk in pool */ 63 atomic_t avail; 64 phys_addr_t phys_addr; /* physical starting address of memory chunk */ 65 unsigned long start_addr; /* starting address of memory chunk */ 66 unsigned long end_addr; /* ending address of memory chunk */ 67 unsigned long bits[0]; /* bitmap for allocating memory chunk */ 68 }; 69 70 extern struct gen_pool *gen_pool_create(int, int); 71 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 72 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, 73 size_t, int); 74 /** 75 * gen_pool_add - add a new chunk of special memory to the pool 76 * @pool: pool to add new memory chunk to 77 * @addr: starting address of memory chunk to add to pool 78 * @size: size in bytes of the memory chunk to add to pool 79 * @nid: node id of the node the chunk structure and bitmap should be 80 * allocated on, or -1 81 * 82 * Add a new chunk of special memory to the specified pool. 83 * 84 * Returns 0 on success or a -ve errno on failure. 85 */ 86 static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 87 size_t size, int nid) 88 { 89 return gen_pool_add_virt(pool, addr, -1, size, nid); 90 } 91 extern void gen_pool_destroy(struct gen_pool *); 92 extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); 93 extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); 94 extern void gen_pool_for_each_chunk(struct gen_pool *, 95 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 96 extern size_t gen_pool_avail(struct gen_pool *); 97 extern size_t gen_pool_size(struct gen_pool *); 98 99 extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 100 void *data); 101 102 extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 103 unsigned long start, unsigned int nr, void *data); 104 105 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 106 unsigned long start, unsigned int nr, void *data); 107 108 #endif /* __GENALLOC_H__ */ 109