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