[linux.git] / include / linux / dm-io.h

/*
 * Copyright (C) 2003 Sistina Software
 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
 *
 * Device-Mapper low-level I/O.
 *
 * This file is released under the GPL.
 */

#ifndef _LINUX_DM_IO_H
#define _LINUX_DM_IO_H

#ifdef __KERNEL__

#include <linux/types.h>

struct dm_io_region {
	struct block_device *bdev;
	sector_t sector;
	sector_t count;		/* If this is zero the region is ignored. */
};

struct page_list {
	struct page_list *next;
	struct page *page;
};

typedef void (*io_notify_fn)(unsigned long error, void *context);

enum dm_io_mem_type {
	DM_IO_PAGE_LIST,/* Page list */
	DM_IO_BVEC,	/* Bio vector */
	DM_IO_VMA,	/* Virtual memory area */
	DM_IO_KMEM,	/* Kernel memory */
};

struct dm_io_memory {
	enum dm_io_mem_type type;

	unsigned offset;

	union {
		struct page_list *pl;
		struct bio_vec *bvec;
		void *vma;
		void *addr;
	} ptr;
};

struct dm_io_notify {
	io_notify_fn fn;	/* Callback for asynchronous requests */
	void *context;		/* Passed to callback */
};

/*
 * IO request structure
 */
struct dm_io_client;
struct dm_io_request {
	int bi_rw;			/* READ|WRITE - not READA */
	struct dm_io_memory mem;	/* Memory to use for io */
	struct dm_io_notify notify;	/* Synchronous if notify.fn is NULL */
	struct dm_io_client *client;	/* Client memory handler */
};

/*
 * For async io calls, users can alternatively use the dm_io() function below
 * and dm_io_client_create() to create private mempools for the client.
 *
 * Create/destroy may block.
 */
struct dm_io_client *dm_io_client_create(void);
void dm_io_client_destroy(struct dm_io_client *client);

/*
 * IO interface using private per-client pools.
 * Each bit in the optional 'sync_error_bits' bitset indicates whether an
 * error occurred doing io to the corresponding region.
 */
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
	  struct dm_io_region *region, unsigned long *sync_error_bits);

#endif	/* __KERNEL__ */
#endif	/* _LINUX_DM_IO_H */
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Copyright (C) 2003 Sistina Software
22a1ceb1 HM	3	* Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
	4	*
	5	* Device-Mapper low-level I/O.
1da177e4 LT	6	*
	7	* This file is released under the GPL.
	8	*/
	9
22a1ceb1 HM	10	#ifndef _LINUX_DM_IO_H
	11	#define _LINUX_DM_IO_H
	12
	13	#ifdef __KERNEL__
1da177e4	14
22a1ceb1	15	#include <linux/types.h>
1da177e4	16
22a1ceb1	17	struct dm_io_region {
1da177e4 LT	18	struct block_device *bdev;
1da177e4 LT	19	sector_t sector;
bf17ce3a	20	sector_t count; /* If this is zero the region is ignored. */
1da177e4 LT	21	};
	22
	23	struct page_list {
	24	struct page_list *next;
	25	struct page *page;
	26	};
	27
1da177e4 LT	28	typedef void (io_notify_fn)(unsigned long error, void context);
1da177e4 LT	29
c8b03afe HM	30	enum dm_io_mem_type {
	31	DM_IO_PAGE_LIST,/* Page list */
	32	DM_IO_BVEC, /* Bio vector */
	33	DM_IO_VMA, /* Virtual memory area */
	34	DM_IO_KMEM, /* Kernel memory */
	35	};
	36
	37	struct dm_io_memory {
	38	enum dm_io_mem_type type;
	39
924e600d MS	40	unsigned offset;
924e600d MS	41
c8b03afe HM	42	union {
	43	struct page_list *pl;
	44	struct bio_vec *bvec;
	45	void *vma;
	46	void *addr;
	47	} ptr;
c8b03afe HM	48	};
	49
	50	struct dm_io_notify {
	51	io_notify_fn fn; /* Callback for asynchronous requests */
	52	void context; / Passed to callback */
	53	};
	54
	55	/*
	56	* IO request structure
	57	*/
	58	struct dm_io_client;
	59	struct dm_io_request {
	60	int bi_rw; /* READ\|WRITE - not READA */
	61	struct dm_io_memory mem; /* Memory to use for io */
	62	struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */
	63	struct dm_io_client client; / Client memory handler */
	64	};
1da177e4	65
c8b03afe HM	66	/*
	67	* For async io calls, users can alternatively use the dm_io() function below
	68	* and dm_io_client_create() to create private mempools for the client.
	69	*
	70	* Create/destroy may block.
	71	*/
bda8efec	72	struct dm_io_client *dm_io_client_create(void);
c8b03afe HM	73	void dm_io_client_destroy(struct dm_io_client *client);
c8b03afe HM	74
c8b03afe HM	75	/*
c8b03afe HM	76	* IO interface using private per-client pools.
bf17ce3a MB	77	* Each bit in the optional 'sync_error_bits' bitset indicates whether an
bf17ce3a MB	78	* error occurred doing io to the corresponding region.
c8b03afe HM	79	*/
c8b03afe HM	80	int dm_io(struct dm_io_request *io_req, unsigned num_regions,
22a1ceb1	81	struct dm_io_region region, unsigned long sync_error_bits);
c8b03afe	82
22a1ceb1 HM	83	#endif /* __KERNEL__ */
22a1ceb1 HM	84	#endif /* _LINUX_DM_IO_H */