Edit File: genalloc.h
/* * Basic general purpose allocator for managing special purpose * memory, for example, memory that is not managed by the regular * kmalloc/kfree interface. Uses for this includes on-device special * memory, uncached memory etc. * * It is safe to use the allocator in NMI handlers and other special * unblockable contexts that could otherwise deadlock on locks. This * is implemented by using atomic operations and retries on any * conflicts. The disadvantage is that there may be livelocks in * extreme cases. For better scalability, one allocator can be used * for each CPU. * * The lockless operation only works if there is enough memory * available. If new memory is added to the pool a lock has to be * still taken. So any user relying on locklessness has to ensure * that sufficient memory is preallocated. * * The basic atomic operation of this allocator is cmpxchg on long. * On architectures that don't have NMI-safe cmpxchg implementation, * the allocator can NOT be used in NMI handler. So code uses the * allocator in NMI handler should depend on * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #ifndef __GENALLOC_H__ #define __GENALLOC_H__ #include <linux/types.h> #include <linux/spinlock_types.h> #include <linux/atomic.h> struct device; struct device_node; struct gen_pool; /** * Allocation callback function type definition * @map: Pointer to bitmap * @size: The bitmap size in bits * @start: The bitnumber to start searching at * @nr: The number of zeroed bits we're looking for * @data: optional additional data used by @genpool_algo_t */ typedef unsigned long (*genpool_algo_t)(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data, struct gen_pool *pool); /* * General purpose special memory pool descriptor. */ struct gen_pool { spinlock_t lock; struct list_head chunks; /* list of chunks in this pool */ int min_alloc_order; /* minimum allocation order */ genpool_algo_t algo; /* allocation function */ void *data; }; /* * General purpose special memory pool chunk descriptor. */ struct gen_pool_chunk { struct list_head next_chunk; /* next chunk in pool */ atomic_long_t avail; phys_addr_t phys_addr; /* physical starting address of memory chunk */ unsigned long start_addr; /* start address of memory chunk */ unsigned long end_addr; /* end address of memory chunk (inclusive) */ unsigned long bits[0]; /* bitmap for allocating memory chunk */ }; /* * gen_pool data descriptor for gen_pool_first_fit_align. */ struct genpool_data_align { int align; /* alignment by bytes for starting address */ }; extern struct gen_pool *gen_pool_create(int, int); extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, size_t, int); /** * gen_pool_add - add a new chunk of special memory to the pool * @pool: pool to add new memory chunk to * @addr: starting address of memory chunk to add to pool * @size: size in bytes of the memory chunk to add to pool * @nid: node id of the node the chunk structure and bitmap should be * allocated on, or -1 * * Add a new chunk of special memory to the specified pool. * * Returns 0 on success or a -ve errno on failure. */ static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size, int nid) { return gen_pool_add_virt(pool, addr, -1, size, nid); } extern void gen_pool_destroy(struct gen_pool *); extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t, genpool_algo_t algo, void *data); extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); extern void gen_pool_for_each_chunk(struct gen_pool *, void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); extern size_t gen_pool_avail(struct gen_pool *); extern size_t gen_pool_size(struct gen_pool *); extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data); extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data, struct gen_pool *pool); extern unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data, struct gen_pool *pool); extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data, struct gen_pool *pool); extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data, struct gen_pool *pool); extern struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order, int nid); extern struct gen_pool *dev_get_gen_pool(struct device *dev); #ifdef CONFIG_OF extern struct gen_pool *of_get_named_gen_pool(struct device_node *np, const char *propname, int index); #else static inline struct gen_pool *of_get_named_gen_pool(struct device_node *np, const char *propname, int index) { return NULL; } #endif #endif /* __GENALLOC_H__ */