You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
358 lines
11 KiB
358 lines
11 KiB
/*
|
|
* 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>
|
|
|
|
/* 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 int (bio_end_io_t) (struct bio *, unsigned int, 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;
|
|
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
|
|
|
|
/*
|
|
* 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))
|
|
|
|
/*
|
|
* 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, bytes) bio_endio((bio), (bytes), -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, 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 *, unsigned int, 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_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,
|
|
unsigned int);
|
|
extern void bio_set_pages_dirty(struct bio *bio);
|
|
extern void bio_check_pages_dirty(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 /* __LINUX_BIO_H */
|
|
|