LXR linux/include/linux/zpool.h

   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
  14struct zpool;
  15
  16struct 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 */
  31enum 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
  39bool zpool_has_pool(char *type);
  40
  41struct zpool *zpool_create_pool(const char *type, const char *name,
  42                        gfp_t gfp, const struct zpool_ops *ops);
  43
  44const char *zpool_get_type(struct zpool *pool);
  45
  46void zpool_destroy_pool(struct zpool *pool);
  47
  48int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
  49                        unsigned long *handle);
  50
  51void zpool_free(struct zpool *pool, unsigned long handle);
  52
  53int zpool_shrink(struct zpool *pool, unsigned int pages,
  54                        unsigned int *reclaimed);
  55
  56void *zpool_map_handle(struct zpool *pool, unsigned long handle,
  57                        enum zpool_mapmode mm);
  58
  59void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
  60
  61u64 zpool_get_total_size(struct zpool *pool);
  62
  63
  64/**
  65 * struct zpool_driver - driver implementation for zpool
  66 * @type:       name of the driver.
  67 * @list:       entry in the list of zpool drivers.
  68 * @create:     create a new pool.
  69 * @destroy:    destroy a pool.
  70 * @malloc:     allocate mem from a pool.
  71 * @free:       free mem from a pool.
  72 * @shrink:     shrink the pool.
  73 * @map:        map a handle.
  74 * @unmap:      unmap a handle.
  75 * @total_size: get total size of a pool.
  76 *
  77 * This is created by a zpool implementation and registered
  78 * with zpool.
  79 */
  80struct zpool_driver {
  81        char *type;
  82        struct module *owner;
  83        atomic_t refcount;
  84        struct list_head list;
  85
  86        void *(*create)(const char *name,
  87                        gfp_t gfp,
  88                        const struct zpool_ops *ops,
  89                        struct zpool *zpool);
  90        void (*destroy)(void *pool);
  91
  92        int (*malloc)(void *pool, size_t size, gfp_t gfp,
  93                                unsigned long *handle);
  94        void (*free)(void *pool, unsigned long handle);
  95
  96        int (*shrink)(void *pool, unsigned int pages,
  97                                unsigned int *reclaimed);
  98
  99        void *(*map)(void *pool, unsigned long handle,
 100                                enum zpool_mapmode mm);
 101        void (*unmap)(void *pool, unsigned long handle);
 102
 103        u64 (*total_size)(void *pool);
 104};
 105
 106void zpool_register_driver(struct zpool_driver *driver);
 107
 108int zpool_unregister_driver(struct zpool_driver *driver);
 109
 110#endif
 111