1 /* 2 * zpool memory storage api 3 * 4 * Copyright (C) 2014 Dan Streetman 5 * 6 * This is a common frontend for the zbud and zsmalloc memory 7 * storage pool implementations. Typically, this is used to 8 * store compressed memory. 9 */ 10 11 #ifndef _ZPOOL_H_ 12 #define _ZPOOL_H_ 13 14 struct zpool; 15 16 struct zpool_ops { 17 int (*evict)(struct zpool *pool, unsigned long handle); 18 }; 19 20 /* 21 * Control how a handle is mapped. It will be ignored if the 22 * implementation does not support it. Its use is optional. 23 * Note that this does not refer to memory protection, it 24 * refers to how the memory will be copied in/out if copying 25 * is necessary during mapping; read-write is the safest as 26 * it copies the existing memory in on map, and copies the 27 * changed memory back out on unmap. Write-only does not copy 28 * in the memory and should only be used for initialization. 29 * If in doubt, use ZPOOL_MM_DEFAULT which is read-write. 30 */ 31 enum zpool_mapmode { 32 ZPOOL_MM_RW, /* normal read-write mapping */ 33 ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */ 34 ZPOOL_MM_WO, /* write-only (no copy-in at map time) */ 35 36 ZPOOL_MM_DEFAULT = ZPOOL_MM_RW 37 }; 38 39 struct zpool *zpool_create_pool(char *type, gfp_t gfp, struct zpool_ops *ops); 40 41 char *zpool_get_type(struct zpool *pool); 42 43 void zpool_destroy_pool(struct zpool *pool); 44 45 int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp, 46 unsigned long *handle); 47 48 void zpool_free(struct zpool *pool, unsigned long handle); 49 50 int zpool_shrink(struct zpool *pool, unsigned int pages, 51 unsigned int *reclaimed); 52 53 void *zpool_map_handle(struct zpool *pool, unsigned long handle, 54 enum zpool_mapmode mm); 55 56 void zpool_unmap_handle(struct zpool *pool, unsigned long handle); 57 58 u64 zpool_get_total_size(struct zpool *pool); 59 60 61 /** 62 * struct zpool_driver - driver implementation for zpool 63 * @type: name of the driver. 64 * @list: entry in the list of zpool drivers. 65 * @create: create a new pool. 66 * @destroy: destroy a pool. 67 * @malloc: allocate mem from a pool. 68 * @free: free mem from a pool. 69 * @shrink: shrink the pool. 70 * @map: map a handle. 71 * @unmap: unmap a handle. 72 * @total_size: get total size of a pool. 73 * 74 * This is created by a zpool implementation and registered 75 * with zpool. 76 */ 77 struct zpool_driver { 78 char *type; 79 struct module *owner; 80 atomic_t refcount; 81 struct list_head list; 82 83 void *(*create)(gfp_t gfp, struct zpool_ops *ops); 84 void (*destroy)(void *pool); 85 86 int (*malloc)(void *pool, size_t size, gfp_t gfp, 87 unsigned long *handle); 88 void (*free)(void *pool, unsigned long handle); 89 90 int (*shrink)(void *pool, unsigned int pages, 91 unsigned int *reclaimed); 92 93 void *(*map)(void *pool, unsigned long handle, 94 enum zpool_mapmode mm); 95 void (*unmap)(void *pool, unsigned long handle); 96 97 u64 (*total_size)(void *pool); 98 }; 99 100 void zpool_register_driver(struct zpool_driver *driver); 101 102 int zpool_unregister_driver(struct zpool_driver *driver); 103 104 int zpool_evict(void *pool, unsigned long handle); 105 106 #endif 107