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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
39struct zpool *zpool_create_pool(char *type, gfp_t gfp, struct zpool_ops *ops);
40
41char *zpool_get_type(struct zpool *pool);
42
43void zpool_destroy_pool(struct zpool *pool);
44
45int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
46 unsigned long *handle);
47
48void zpool_free(struct zpool *pool, unsigned long handle);
49
50int zpool_shrink(struct zpool *pool, unsigned int pages,
51 unsigned int *reclaimed);
52
53void *zpool_map_handle(struct zpool *pool, unsigned long handle,
54 enum zpool_mapmode mm);
55
56void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
57
58u64 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 */
77struct 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
100void zpool_register_driver(struct zpool_driver *driver);
101
102int zpool_unregister_driver(struct zpool_driver *driver);
103
104int zpool_evict(void *pool, unsigned long handle);
105
106#endif