mm: zpool: remove object mapping APIs

struct zpool;

/*

 * 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);

void zpool_free(struct zpool *pool, unsigned long handle);

void *zpool_map_handle(struct zpool *pool, unsigned long handle,

			enum zpool_mapmode mm);

void zpool_unmap_handle(struct zpool *pool, unsigned long handle);

void *zpool_obj_read_begin(struct zpool *zpool, unsigned long handle,

			   void *local_copy);

				unsigned long *handle);

	void (*free)(void *pool, unsigned long handle);

	bool sleep_mapped;

	void *(*map)(void *pool, unsigned long handle,

				enum zpool_mapmode mm);

	void (*unmap)(void *pool, unsigned long handle);

	void *(*obj_read_begin)(void *pool, unsigned long handle,

				void *local_copy);

	void (*obj_read_end)(void *pool, unsigned long handle,

	zpool->driver->free(zpool->pool, handle);

}

/**

 * zpool_map_handle() - Map a previously allocated handle into memory

 * @zpool:	The zpool that the handle was allocated from

 * @handle:	The handle to map

 * @mapmode:	How the memory should be mapped

 *

 * This maps a previously allocated handle into memory.  The @mapmode

 * param indicates to the implementation how the memory will be

 * used, i.e. read-only, write-only, read-write.  If the

 * implementation does not support it, the memory will be treated

 * as read-write.

 *

 * This may hold locks, disable interrupts, and/or preemption,

 * and the zpool_unmap_handle() must be called to undo those

 * actions.  The code that uses the mapped handle should complete

 * its operations on the mapped handle memory quickly and unmap

 * as soon as possible.  As the implementation may use per-cpu

 * data, multiple handles should not be mapped concurrently on

 * any cpu.

 *

 * Returns: A pointer to the handle's mapped memory area.

 */

void *zpool_map_handle(struct zpool *zpool, unsigned long handle,

			enum zpool_mapmode mapmode)

{

	return zpool->driver->map(zpool->pool, handle, mapmode);

}

/**

 * zpool_unmap_handle() - Unmap a previously mapped handle

 * @zpool:	The zpool that the handle was allocated from

 * @handle:	The handle to unmap

 *

 * This unmaps a previously mapped handle.  Any locks or other

 * actions that the implementation took in zpool_map_handle()

 * will be undone here.  The memory area returned from

 * zpool_map_handle() should no longer be used after this.

 */

void zpool_unmap_handle(struct zpool *zpool, unsigned long handle)

{

	zpool->driver->unmap(zpool->pool, handle);

}

/**

 * zpool_obj_read_begin() - Start reading from a previously allocated handle.

 * @zpool:	The zpool that the handle was allocated from

	return zpool->driver->total_pages(zpool->pool);

}

/**

 * zpool_can_sleep_mapped - Test if zpool can sleep when do mapped.

 * @zpool:	The zpool to test

 *

 * Some allocators enter non-preemptible context in ->map() callback (e.g.

 * disable pagefaults) and exit that context in ->unmap(), which limits what

 * we can do with the mapped object. For instance, we cannot wait for

 * asynchronous crypto API to decompress such an object or take mutexes

 * since those will call into the scheduler. This function tells us whether

 * we use such an allocator.

 *

 * Returns: true if zpool can sleep; false otherwise.

 */

bool zpool_can_sleep_mapped(struct zpool *zpool)

{

	return zpool->driver->sleep_mapped;

}

MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");

MODULE_DESCRIPTION("Common API for compressed memory storage");

	zs_free(pool, handle);

}

static void *zs_zpool_map(void *pool, unsigned long handle,

			enum zpool_mapmode mm)

{

	enum zs_mapmode zs_mm;

	switch (mm) {

	case ZPOOL_MM_RO:

		zs_mm = ZS_MM_RO;

		break;

	case ZPOOL_MM_WO:

		zs_mm = ZS_MM_WO;

		break;

	case ZPOOL_MM_RW:

	default:

		zs_mm = ZS_MM_RW;

		break;

	}

	return zs_map_object(pool, handle, zs_mm);

}

static void zs_zpool_unmap(void *pool, unsigned long handle)

{

	zs_unmap_object(pool, handle);

}

static void *zs_zpool_obj_read_begin(void *pool, unsigned long handle,

				     void *local_copy)

{

	.malloc_support_movable = true,

	.malloc =		  zs_zpool_malloc,

	.free =			  zs_zpool_free,

	.map =			  zs_zpool_map,

	.unmap =		  zs_zpool_unmap,

	.obj_read_begin =	  zs_zpool_obj_read_begin,

	.obj_read_end  =	  zs_zpool_obj_read_end,

	.obj_write =		  zs_zpool_obj_write,