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