LXR linux/include/linux/zpool.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * zpool memory storage api
   4 *
   5 * Copyright (C) 2014 Dan Streetman
   6 *
   7 * This is a common frontend for the zbud and zsmalloc memory
   8 * storage pool implementations.  Typically, this is used to
   9 * store compressed memory.
  10 */
  11
  12#ifndef _ZPOOL_H_
  13#define _ZPOOL_H_
  14
  15struct zpool;
  16
  17struct zpool_ops {
  18        int (*evict)(struct zpool *pool, unsigned long handle);
  19};
  20
  21/*
  22 * Control how a handle is mapped.  It will be ignored if the
  23 * implementation does not support it.  Its use is optional.
  24 * Note that this does not refer to memory protection, it
  25 * refers to how the memory will be copied in/out if copying
  26 * is necessary during mapping; read-write is the safest as
  27 * it copies the existing memory in on map, and copies the
  28 * changed memory back out on unmap.  Write-only does not copy
  29 * in the memory and should only be used for initialization.
  30 * If in doubt, use ZPOOL_MM_DEFAULT which is read-write.
  31 */
  32enum zpool_mapmode {
  33        ZPOOL_MM_RW, /* normal read-write mapping */
  34        ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */
  35        ZPOOL_MM_WO, /* write-only (no copy-in at map time) */
  36
  37        ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
  38};
  39
  40bool zpool_has_pool(char *type);
  41
  42struct zpool *zpool_create_pool(const char *type, const char *name,
  43                        gfp_t gfp, const struct zpool_ops *ops);
  44
  45const char *zpool_get_type(struct zpool *pool);
  46
  47void zpool_destroy_pool(struct zpool *pool);
  48
  49int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
  50                        unsigned long *handle);
  51
  52void zpool_free(struct zpool *pool, unsigned long handle);
  53
  54int zpool_shrink(struct zpool *pool, unsigned int pages,
  55                        unsigned int *reclaimed);
  56
  57void *zpool_map_handle(struct zpool *pool, unsigned long handle,
  58                        enum zpool_mapmode mm);
  59
  60void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
  61
  62u64 zpool_get_total_size(struct zpool *pool);
  63
  64
  65/**
  66 * struct zpool_driver - driver implementation for zpool
  67 * @type:       name of the driver.
  68 * @list:       entry in the list of zpool drivers.
  69 * @create:     create a new pool.
  70 * @destroy:    destroy a pool.
  71 * @malloc:     allocate mem from a pool.
  72 * @free:       free mem from a pool.
  73 * @shrink:     shrink the pool.
  74 * @map:        map a handle.
  75 * @unmap:      unmap a handle.
  76 * @total_size: get total size of a pool.
  77 *
  78 * This is created by a zpool implementation and registered
  79 * with zpool.
  80 */
  81struct zpool_driver {
  82        char *type;
  83        struct module *owner;
  84        atomic_t refcount;
  85        struct list_head list;
  86
  87        void *(*create)(const char *name,
  88                        gfp_t gfp,
  89                        const struct zpool_ops *ops,
  90                        struct zpool *zpool);
  91        void (*destroy)(void *pool);
  92
  93        int (*malloc)(void *pool, size_t size, gfp_t gfp,
  94                                unsigned long *handle);
  95        void (*free)(void *pool, unsigned long handle);
  96
  97        int (*shrink)(void *pool, unsigned int pages,
  98                                unsigned int *reclaimed);
  99
 100        void *(*map)(void *pool, unsigned long handle,
 101                                enum zpool_mapmode mm);
 102        void (*unmap)(void *pool, unsigned long handle);
 103
 104        u64 (*total_size)(void *pool);
 105};
 106
 107void zpool_register_driver(struct zpool_driver *driver);
 108
 109int zpool_unregister_driver(struct zpool_driver *driver);
 110
 111bool zpool_evictable(struct zpool *pool);
 112
 113#endif
 114