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