[linux-block.git] / include / linux / bio.h

/*
 * 2.5 block I/O model
 *
 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 */
#ifndef __LINUX_BIO_H
#define __LINUX_BIO_H

#include <linux/highmem.h>
#include <linux/mempool.h>
#include <linux/ioprio.h>

#ifdef CONFIG_BLOCK

/* Platforms may set this to teach the BIO layer about IOMMU hardware. */
#include <asm/io.h>

#if defined(BIO_VMERGE_MAX_SIZE) && defined(BIO_VMERGE_BOUNDARY)
#define BIOVEC_VIRT_START_SIZE(x) (bvec_to_phys(x) & (BIO_VMERGE_BOUNDARY - 1))
#define BIOVEC_VIRT_OVERSIZE(x)	((x) > BIO_VMERGE_MAX_SIZE)
#else
#define BIOVEC_VIRT_START_SIZE(x)	0
#define BIOVEC_VIRT_OVERSIZE(x)		0
#endif

#ifndef BIO_VMERGE_BOUNDARY
#define BIO_VMERGE_BOUNDARY	0
#endif

#define BIO_DEBUG

#ifdef BIO_DEBUG
#define BIO_BUG_ON	BUG_ON
#else
#define BIO_BUG_ON
#endif

#define BIO_MAX_PAGES		256
#define BIO_MAX_SIZE		(BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
#define BIO_MAX_SECTORS		(BIO_MAX_SIZE >> 9)

/*
 * was unsigned short, but we might as well be ready for > 64kB I/O pages
 */
struct bio_vec {
	struct page	*bv_page;
	unsigned int	bv_len;
	unsigned int	bv_offset;
};

struct bio_set;
struct bio;
typedef void (bio_end_io_t) (struct bio *, int);
typedef void (bio_destructor_t) (struct bio *);

/*
 * main unit of I/O for the block layer and lower layers (ie drivers and
 * stacking drivers)
 */
struct bio {
	sector_t		bi_sector;	/* device address in 512 byte
						   sectors */
	struct bio		*bi_next;	/* request queue link */
	struct block_device	*bi_bdev;
	unsigned long		bi_flags;	/* status, command, etc */
	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
						 * top bits priority
						 */

	unsigned short		bi_vcnt;	/* how many bio_vec's */
	unsigned short		bi_idx;		/* current index into bvl_vec */

	/* Number of segments in this BIO after
	 * physical address coalescing is performed.
	 */
	unsigned short		bi_phys_segments;

	/* Number of segments after physical and DMA remapping
	 * hardware coalescing is performed.
	 */
	unsigned short		bi_hw_segments;

	unsigned int		bi_size;	/* residual I/O count */

	/*
	 * To keep track of the max hw size, we account for the
	 * sizes of the first and last virtually mergeable segments
	 * in this bio
	 */
	unsigned int		bi_hw_front_size;
	unsigned int		bi_hw_back_size;

	unsigned int		bi_max_vecs;	/* max bvl_vecs we can hold */

	struct bio_vec		*bi_io_vec;	/* the actual vec list */

	bio_end_io_t		*bi_end_io;
	atomic_t		bi_cnt;		/* pin count */

	void			*bi_private;

	bio_destructor_t	*bi_destructor;	/* destructor */
};

/*
 * bio flags
 */
#define BIO_UPTODATE	0	/* ok after I/O completion */
#define BIO_RW_BLOCK	1	/* RW_AHEAD set, and read/write would block */
#define BIO_EOF		2	/* out-out-bounds error */
#define BIO_SEG_VALID	3	/* nr_hw_seg valid */
#define BIO_CLONED	4	/* doesn't own data */
#define BIO_BOUNCED	5	/* bio is a bounce bio */
#define BIO_USER_MAPPED 6	/* contains user pages */
#define BIO_EOPNOTSUPP	7	/* not supported */
#define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))

/*
 * top 4 bits of bio flags indicate the pool this bio came from
 */
#define BIO_POOL_BITS		(4)
#define BIO_POOL_OFFSET		(BITS_PER_LONG - BIO_POOL_BITS)
#define BIO_POOL_MASK		(1UL << BIO_POOL_OFFSET)
#define BIO_POOL_IDX(bio)	((bio)->bi_flags >> BIO_POOL_OFFSET)	

/*
 * bio bi_rw flags
 *
 * bit 0 -- read (not set) or write (set)
 * bit 1 -- rw-ahead when set
 * bit 2 -- barrier
 * bit 3 -- fail fast, don't want low level driver retries
 * bit 4 -- synchronous I/O hint: the block layer will unplug immediately
 */
#define BIO_RW		0
#define BIO_RW_AHEAD	1
#define BIO_RW_BARRIER	2
#define BIO_RW_FAILFAST	3
#define BIO_RW_SYNC	4
#define BIO_RW_META	5

/*
 * upper 16 bits of bi_rw define the io priority of this bio
 */
#define BIO_PRIO_SHIFT	(8 * sizeof(unsigned long) - IOPRIO_BITS)
#define bio_prio(bio)	((bio)->bi_rw >> BIO_PRIO_SHIFT)
#define bio_prio_valid(bio)	ioprio_valid(bio_prio(bio))

#define bio_set_prio(bio, prio)		do {			\
	WARN_ON(prio >= (1 << IOPRIO_BITS));			\
	(bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);		\
	(bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);	\
} while (0)

/*
 * various member access, note that bio_data should of course not be used
 * on highmem page vectors
 */
#define bio_iovec_idx(bio, idx)	(&((bio)->bi_io_vec[(idx)]))
#define bio_iovec(bio)		bio_iovec_idx((bio), (bio)->bi_idx)
#define bio_page(bio)		bio_iovec((bio))->bv_page
#define bio_offset(bio)		bio_iovec((bio))->bv_offset
#define bio_segments(bio)	((bio)->bi_vcnt - (bio)->bi_idx)
#define bio_sectors(bio)	((bio)->bi_size >> 9)
#define bio_cur_sectors(bio)	(bio_iovec(bio)->bv_len >> 9)
#define bio_data(bio)		(page_address(bio_page((bio))) + bio_offset((bio)))
#define bio_barrier(bio)	((bio)->bi_rw & (1 << BIO_RW_BARRIER))
#define bio_sync(bio)		((bio)->bi_rw & (1 << BIO_RW_SYNC))
#define bio_failfast(bio)	((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
#define bio_rw_ahead(bio)	((bio)->bi_rw & (1 << BIO_RW_AHEAD))
#define bio_rw_meta(bio)	((bio)->bi_rw & (1 << BIO_RW_META))

/*
 * will die
 */
#define bio_to_phys(bio)	(page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
#define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)

/*
 * queues that have highmem support enabled may still need to revert to
 * PIO transfers occasionally and thus map high pages temporarily. For
 * permanent PIO fall back, user is probably better off disabling highmem
 * I/O completely on that queue (see ide-dma for example)
 */
#define __bio_kmap_atomic(bio, idx, kmtype)				\
	(kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +	\
		bio_iovec_idx((bio), (idx))->bv_offset)

#define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)

/*
 * merge helpers etc
 */

#define __BVEC_END(bio)		bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
#define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_idx)

/*
 * allow arch override, for eg virtualized architectures (put in asm/io.h)
 */
#ifndef BIOVEC_PHYS_MERGEABLE
#define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
#endif

#define BIOVEC_VIRT_MERGEABLE(vec1, vec2)	\
	((((bvec_to_phys((vec1)) + (vec1)->bv_len) | bvec_to_phys((vec2))) & (BIO_VMERGE_BOUNDARY - 1)) == 0)
#define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
#define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
#define BIO_SEG_BOUNDARY(q, b1, b2) \
	BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))

#define bio_io_error(bio) bio_endio((bio), -EIO)

/*
 * drivers should not use the __ version unless they _really_ want to
 * run through the entire bio and not just pending pieces
 */
#define __bio_for_each_segment(bvl, bio, i, start_idx)			\
	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);	\
	     i < (bio)->bi_vcnt;					\
	     bvl++, i++)

#define bio_for_each_segment(bvl, bio, i)				\
	__bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)

/*
 * get a reference to a bio, so it won't disappear. the intended use is
 * something like:
 *
 * bio_get(bio);
 * submit_bio(rw, bio);
 * if (bio->bi_flags ...)
 *	do_something
 * bio_put(bio);
 *
 * without the bio_get(), it could potentially complete I/O before submit_bio
 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 * runs
 */
#define bio_get(bio)	atomic_inc(&(bio)->bi_cnt)


/*
 * A bio_pair is used when we need to split a bio.
 * This can only happen for a bio that refers to just one
 * page of data, and in the unusual situation when the
 * page crosses a chunk/device boundary
 *
 * The address of the master bio is stored in bio1.bi_private
 * The address of the pool the pair was allocated from is stored
 *   in bio2.bi_private
 */
struct bio_pair {
	struct bio	bio1, bio2;
	struct bio_vec	bv1, bv2;
	atomic_t	cnt;
	int		error;
};
extern struct bio_pair *bio_split(struct bio *bi, mempool_t *pool,
				  int first_sectors);
extern mempool_t *bio_split_pool;
extern void bio_pair_release(struct bio_pair *dbio);

extern struct bio_set *bioset_create(int, int);
extern void bioset_free(struct bio_set *);

extern struct bio *bio_alloc(gfp_t, int);
extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
extern void bio_put(struct bio *);
extern void bio_free(struct bio *, struct bio_set *);

extern void bio_endio(struct bio *, int);
struct request_queue;
extern int bio_phys_segments(struct request_queue *, struct bio *);
extern int bio_hw_segments(struct request_queue *, struct bio *);

extern void __bio_clone(struct bio *, struct bio *);
extern struct bio *bio_clone(struct bio *, gfp_t);

extern void bio_init(struct bio *);

extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
			   unsigned int, unsigned int);
extern int bio_get_nr_vecs(struct block_device *);
extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
				unsigned long, unsigned int, int);
struct sg_iovec;
extern struct bio *bio_map_user_iov(struct request_queue *,
				    struct block_device *,
				    struct sg_iovec *, int, int);
extern void bio_unmap_user(struct bio *);
extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
				gfp_t);
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
extern void bio_release_pages(struct bio *bio);
extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
extern int bio_uncopy_user(struct bio *);
void zero_fill_bio(struct bio *bio);

#ifdef CONFIG_HIGHMEM
/*
 * remember to add offset! and never ever reenable interrupts between a
 * bvec_kmap_irq and bvec_kunmap_irq!!
 *
 * This function MUST be inlined - it plays with the CPU interrupt flags.
 */
static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
{
	unsigned long addr;

	/*
	 * might not be a highmem page, but the preempt/irq count
	 * balancing is a lot nicer this way
	 */
	local_irq_save(*flags);
	addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);

	BUG_ON(addr & ~PAGE_MASK);

	return (char *) addr + bvec->bv_offset;
}

static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
{
	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;

	kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
	local_irq_restore(*flags);
}

#else
#define bvec_kmap_irq(bvec, flags)	(page_address((bvec)->bv_page) + (bvec)->bv_offset)
#define bvec_kunmap_irq(buf, flags)	do { *(flags) = 0; } while (0)
#endif

static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
				   unsigned long *flags)
{
	return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
}
#define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)

#define bio_kmap_irq(bio, flags) \
	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
#define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)

#endif /* CONFIG_BLOCK */
#endif /* __LINUX_BIO_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* 2.5 block I/O model
	3	*
	4	* Copyright (C) 2001 Jens Axboe <axboe@suse.de>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public Licens
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
	19	*/
	20	#ifndef __LINUX_BIO_H
	21	#define __LINUX_BIO_H
	22
	23	#include <linux/highmem.h>
	24	#include <linux/mempool.h>
22e2c507	25	#include <linux/ioprio.h>
1da177e4	26
02a5e0ac DH	27	#ifdef CONFIG_BLOCK
02a5e0ac DH	28
1da177e4 LT	29	/* Platforms may set this to teach the BIO layer about IOMMU hardware. */
	30	#include <asm/io.h>
	31
	32	#if defined(BIO_VMERGE_MAX_SIZE) && defined(BIO_VMERGE_BOUNDARY)
	33	#define BIOVEC_VIRT_START_SIZE(x) (bvec_to_phys(x) & (BIO_VMERGE_BOUNDARY - 1))
	34	#define BIOVEC_VIRT_OVERSIZE(x) ((x) > BIO_VMERGE_MAX_SIZE)
	35	#else
	36	#define BIOVEC_VIRT_START_SIZE(x) 0
	37	#define BIOVEC_VIRT_OVERSIZE(x) 0
	38	#endif
	39
	40	#ifndef BIO_VMERGE_BOUNDARY
	41	#define BIO_VMERGE_BOUNDARY 0
	42	#endif
	43
	44	#define BIO_DEBUG
	45
	46	#ifdef BIO_DEBUG
	47	#define BIO_BUG_ON BUG_ON
	48	#else
	49	#define BIO_BUG_ON
	50	#endif
	51
d84a8477	52	#define BIO_MAX_PAGES 256
1da177e4 LT	53	#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
	54	#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
	55
	56	/*
	57	* was unsigned short, but we might as well be ready for > 64kB I/O pages
	58	*/
	59	struct bio_vec {
	60	struct page *bv_page;
	61	unsigned int bv_len;
	62	unsigned int bv_offset;
	63	};
	64
	65	struct bio_set;
	66	struct bio;
6712ecf8	67	typedef void (bio_end_io_t) (struct bio *, int);
1da177e4 LT	68	typedef void (bio_destructor_t) (struct bio *);
	69
	70	/*
	71	* main unit of I/O for the block layer and lower layers (ie drivers and
	72	* stacking drivers)
	73	*/
	74	struct bio {
2c2345c2 RG	75	sector_t bi_sector; /* device address in 512 byte
2c2345c2 RG	76	sectors */
1da177e4 LT	77	struct bio bi_next; / request queue link */
	78	struct block_device *bi_bdev;
	79	unsigned long bi_flags; /* status, command, etc */
	80	unsigned long bi_rw; /* bottom bits READ/WRITE,
	81	* top bits priority
	82	*/
	83
	84	unsigned short bi_vcnt; /* how many bio_vec's */
	85	unsigned short bi_idx; /* current index into bvl_vec */
	86
	87	/* Number of segments in this BIO after
	88	* physical address coalescing is performed.
	89	*/
	90	unsigned short bi_phys_segments;
	91
	92	/* Number of segments after physical and DMA remapping
	93	* hardware coalescing is performed.
	94	*/
	95	unsigned short bi_hw_segments;
	96
	97	unsigned int bi_size; /* residual I/O count */
	98
	99	/*
	100	* To keep track of the max hw size, we account for the
	101	* sizes of the first and last virtually mergeable segments
	102	* in this bio
	103	*/
	104	unsigned int bi_hw_front_size;
	105	unsigned int bi_hw_back_size;
	106
	107	unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
	108
	109	struct bio_vec bi_io_vec; / the actual vec list */
	110
	111	bio_end_io_t *bi_end_io;
	112	atomic_t bi_cnt; /* pin count */
	113
	114	void *bi_private;
	115
	116	bio_destructor_t bi_destructor; / destructor */
1da177e4 LT	117	};
	118
	119	/*
	120	* bio flags
	121	*/
	122	#define BIO_UPTODATE 0 /* ok after I/O completion */
	123	#define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */
	124	#define BIO_EOF 2 /* out-out-bounds error */
	125	#define BIO_SEG_VALID 3 /* nr_hw_seg valid */
	126	#define BIO_CLONED 4 /* doesn't own data */
	127	#define BIO_BOUNCED 5 /* bio is a bounce bio */
	128	#define BIO_USER_MAPPED 6 /* contains user pages */
	129	#define BIO_EOPNOTSUPP 7 /* not supported */
	130	#define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
	131
	132	/*
	133	* top 4 bits of bio flags indicate the pool this bio came from
	134	*/
	135	#define BIO_POOL_BITS (4)
	136	#define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS)
	137	#define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
	138	#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
	139
	140	/*
	141	* bio bi_rw flags
	142	*
	143	* bit 0 -- read (not set) or write (set)
	144	* bit 1 -- rw-ahead when set
	145	* bit 2 -- barrier
	146	* bit 3 -- fail fast, don't want low level driver retries
	147	* bit 4 -- synchronous I/O hint: the block layer will unplug immediately
	148	*/
	149	#define BIO_RW 0
	150	#define BIO_RW_AHEAD 1
	151	#define BIO_RW_BARRIER 2
	152	#define BIO_RW_FAILFAST 3
	153	#define BIO_RW_SYNC 4
5404bc7a	154	#define BIO_RW_META 5
1da177e4	155
22e2c507 JA	156	/*
	157	* upper 16 bits of bi_rw define the io priority of this bio
	158	*/
	159	#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
	160	#define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
	161	#define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
	162
	163	#define bio_set_prio(bio, prio) do { \
	164	WARN_ON(prio >= (1 << IOPRIO_BITS)); \
	165	(bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
	166	(bio)->bi_rw \|= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
	167	} while (0)
	168
1da177e4 LT	169	/*
	170	* various member access, note that bio_data should of course not be used
	171	* on highmem page vectors
	172	*/
	173	#define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
	174	#define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx)
	175	#define bio_page(bio) bio_iovec((bio))->bv_page
	176	#define bio_offset(bio) bio_iovec((bio))->bv_offset
	177	#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx)
	178	#define bio_sectors(bio) ((bio)->bi_size >> 9)
	179	#define bio_cur_sectors(bio) (bio_iovec(bio)->bv_len >> 9)
	180	#define bio_data(bio) (page_address(bio_page((bio))) + bio_offset((bio)))
	181	#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
	182	#define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC))
	183	#define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
	184	#define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
5404bc7a	185	#define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META))
1da177e4 LT	186
	187	/*
	188	* will die
	189	*/
	190	#define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
	191	#define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
	192
	193	/*
	194	* queues that have highmem support enabled may still need to revert to
	195	* PIO transfers occasionally and thus map high pages temporarily. For
	196	* permanent PIO fall back, user is probably better off disabling highmem
	197	* I/O completely on that queue (see ide-dma for example)
	198	*/
	199	#define __bio_kmap_atomic(bio, idx, kmtype) \
	200	(kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \
	201	bio_iovec_idx((bio), (idx))->bv_offset)
	202
	203	#define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
	204
	205	/*
	206	* merge helpers etc
	207	*/
	208
	209	#define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
	210	#define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx)
	211
	212	/*
	213	* allow arch override, for eg virtualized architectures (put in asm/io.h)
	214	*/
	215	#ifndef BIOVEC_PHYS_MERGEABLE
	216	#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
	217	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
	218	#endif
	219
	220	#define BIOVEC_VIRT_MERGEABLE(vec1, vec2) \
	221	((((bvec_to_phys((vec1)) + (vec1)->bv_len) \| bvec_to_phys((vec2))) & (BIO_VMERGE_BOUNDARY - 1)) == 0)
	222	#define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
	223	(((addr1) \| (mask)) == (((addr2) - 1) \| (mask)))
	224	#define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
	225	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
	226	#define BIO_SEG_BOUNDARY(q, b1, b2) \
	227	BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
	228
6712ecf8	229	#define bio_io_error(bio) bio_endio((bio), -EIO)
1da177e4 LT	230
	231	/*
	232	* drivers should not use the __ version unless they _really_ want to
	233	* run through the entire bio and not just pending pieces
	234	*/
	235	#define __bio_for_each_segment(bvl, bio, i, start_idx) \
	236	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
	237	i < (bio)->bi_vcnt; \
	238	bvl++, i++)
	239
	240	#define bio_for_each_segment(bvl, bio, i) \
	241	__bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
	242
	243	/*
	244	* get a reference to a bio, so it won't disappear. the intended use is
	245	* something like:
	246	*
	247	* bio_get(bio);
	248	* submit_bio(rw, bio);
	249	* if (bio->bi_flags ...)
	250	* do_something
	251	* bio_put(bio);
	252	*
	253	* without the bio_get(), it could potentially complete I/O before submit_bio
	254	* returns. and then bio would be freed memory when if (bio->bi_flags ...)
	255	* runs
	256	*/
	257	#define bio_get(bio) atomic_inc(&(bio)->bi_cnt)
	258
	259
	260	/*
	261	* A bio_pair is used when we need to split a bio.
	262	* This can only happen for a bio that refers to just one
	263	* page of data, and in the unusual situation when the
	264	* page crosses a chunk/device boundary
	265	*
	266	* The address of the master bio is stored in bio1.bi_private
	267	* The address of the pool the pair was allocated from is stored
	268	* in bio2.bi_private
	269	*/
	270	struct bio_pair {
	271	struct bio bio1, bio2;
	272	struct bio_vec bv1, bv2;
	273	atomic_t cnt;
	274	int error;
	275	};
	276	extern struct bio_pair bio_split(struct bio bi, mempool_t *pool,
	277	int first_sectors);
	278	extern mempool_t *bio_split_pool;
	279	extern void bio_pair_release(struct bio_pair *dbio);
	280
5972511b	281	extern struct bio_set *bioset_create(int, int);
1da177e4 LT	282	extern void bioset_free(struct bio_set *);
1da177e4 LT	283
dd0fc66f AV	284	extern struct bio *bio_alloc(gfp_t, int);
dd0fc66f AV	285	extern struct bio bio_alloc_bioset(gfp_t, int, struct bio_set );
1da177e4	286	extern void bio_put(struct bio *);
3676347a	287	extern void bio_free(struct bio , struct bio_set );
1da177e4	288
6712ecf8	289	extern void bio_endio(struct bio *, int);
1da177e4 LT	290	struct request_queue;
	291	extern int bio_phys_segments(struct request_queue , struct bio );
	292	extern int bio_hw_segments(struct request_queue , struct bio );
	293
	294	extern void __bio_clone(struct bio , struct bio );
dd0fc66f	295	extern struct bio bio_clone(struct bio , gfp_t);
1da177e4 LT	296
	297	extern void bio_init(struct bio *);
	298
	299	extern int bio_add_page(struct bio , struct page , unsigned int,unsigned int);
6e68af66 MC	300	extern int bio_add_pc_page(struct request_queue , struct bio , struct page *,
6e68af66 MC	301	unsigned int, unsigned int);
1da177e4 LT	302	extern int bio_get_nr_vecs(struct block_device *);
	303	extern struct bio bio_map_user(struct request_queue , struct block_device *,
	304	unsigned long, unsigned int, int);
f1970baf JB	305	struct sg_iovec;
	306	extern struct bio bio_map_user_iov(struct request_queue ,
	307	struct block_device *,
	308	struct sg_iovec *, int, int);
1da177e4	309	extern void bio_unmap_user(struct bio *);
df46b9a4	310	extern struct bio bio_map_kern(struct request_queue , void *, unsigned int,
27496a8c	311	gfp_t);
1da177e4 LT	312	extern void bio_set_pages_dirty(struct bio *bio);
1da177e4 LT	313	extern void bio_check_pages_dirty(struct bio *bio);
e61c9018	314	extern void bio_release_pages(struct bio *bio);
1da177e4 LT	315	extern struct bio bio_copy_user(struct request_queue , unsigned long, unsigned int, int);
	316	extern int bio_uncopy_user(struct bio *);
	317	void zero_fill_bio(struct bio *bio);
	318
	319	#ifdef CONFIG_HIGHMEM
	320	/*
	321	* remember to add offset! and never ever reenable interrupts between a
	322	* bvec_kmap_irq and bvec_kunmap_irq!!
	323	*
	324	* This function MUST be inlined - it plays with the CPU interrupt flags.
1da177e4	325	*/
c2d08dad	326	static inline char bvec_kmap_irq(struct bio_vec bvec, unsigned long *flags)
1da177e4 LT	327	{
	328	unsigned long addr;
	329
	330	/*
	331	* might not be a highmem page, but the preempt/irq count
	332	* balancing is a lot nicer this way
	333	*/
	334	local_irq_save(*flags);
	335	addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
	336
	337	BUG_ON(addr & ~PAGE_MASK);
	338
	339	return (char *) addr + bvec->bv_offset;
	340	}
	341
c2d08dad	342	static inline void bvec_kunmap_irq(char buffer, unsigned long flags)
1da177e4 LT	343	{
	344	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
	345
	346	kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
	347	local_irq_restore(*flags);
	348	}
	349
	350	#else
	351	#define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset)
	352	#define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0)
	353	#endif
	354
c2d08dad	355	static inline char __bio_kmap_irq(struct bio bio, unsigned short idx,
1da177e4 LT	356	unsigned long *flags)
	357	{
	358	return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
	359	}
	360	#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
	361
	362	#define bio_kmap_irq(bio, flags) \
	363	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
	364	#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
	365
02a5e0ac	366	#endif /* CONFIG_BLOCK */
1da177e4	367	#endif /* __LINUX_BIO_H */