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/*
* zpool memory storage api
*
* Copyright (C) 2014 Dan Streetman
*
* This is a common frontend for the zbud and zsmalloc memory
* storage pool implementations. Typically, this is used to
* store compressed memory.
*/
#ifndef _ZPOOL_H_
#define _ZPOOL_H_
struct zpool;
struct zpool_ops {
int (*evict)(struct zpool *pool, unsigned long handle);
};
/*
* Control how a handle is mapped. It will be ignored if the
* implementation does not support it. Its use is optional.
* Note that this does not refer to memory protection, it
* refers to how the memory will be copied in/out if copying
* is necessary during mapping; read-write is the safest as
* it copies the existing memory in on map, and copies the
* changed memory back out on unmap. Write-only does not copy
* in the memory and should only be used for initialization.
* If in doubt, use ZPOOL_MM_DEFAULT which is read-write.
*/
enum zpool_mapmode {
ZPOOL_MM_RW, /* normal read-write mapping */
ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */
ZPOOL_MM_WO, /* write-only (no copy-in at map time) */
ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
};
bool zpool_has_pool(char *type);
struct zpool *zpool_create_pool(const char *type, const char *name,
gfp_t gfp, const struct zpool_ops *ops);
const char *zpool_get_type(struct zpool *pool);
void zpool_destroy_pool(struct zpool *pool);
int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
unsigned long *handle);
void zpool_free(struct zpool *pool, unsigned long handle);
int zpool_shrink(struct zpool *pool, unsigned int pages,
unsigned int *reclaimed);
void *zpool_map_handle(struct zpool *pool, unsigned long handle,
enum zpool_mapmode mm);
void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
u64 zpool_get_total_size(struct zpool *pool);
/**
* struct zpool_driver - driver implementation for zpool
* @type: name of the driver.
* @list: entry in the list of zpool drivers.
* @create: create a new pool.
* @destroy: destroy a pool.
* @malloc: allocate mem from a pool.
* @free: free mem from a pool.
* @shrink: shrink the pool.
* @map: map a handle.
* @unmap: unmap a handle.
* @total_size: get total size of a pool.
*
* This is created by a zpool implementation and registered
* with zpool.
*/
struct zpool_driver {
char *type;
struct module *owner;
atomic_t refcount;
struct list_head list;
void *(*create)(const char *name,
gfp_t gfp,
const struct zpool_ops *ops,
struct zpool *zpool);
void (*destroy)(void *pool);
int (*malloc)(void *pool, size_t size, gfp_t gfp,
unsigned long *handle);
void (*free)(void *pool, unsigned long handle);
int (*shrink)(void *pool, unsigned int pages,
unsigned int *reclaimed);
void *(*map)(void *pool, unsigned long handle,
enum zpool_mapmode mm);
void (*unmap)(void *pool, unsigned long handle);
u64 (*total_size)(void *pool);
};
void zpool_register_driver(struct zpool_driver *driver);
int zpool_unregister_driver(struct zpool_driver *driver);
#endif
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