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linux_old1/include/linux/bio.h

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/*
* 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
#include <asm/io.h>
#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;
struct bio_integrity_payload;
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 int bi_phys_segments;
unsigned int bi_size; /* residual I/O count */
/*
* To keep track of the max segment size, we account for the
* sizes of the first and last mergeable segments in this bio.
*/
unsigned int bi_seg_front_size;
unsigned int bi_seg_back_size;
unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
unsigned int bi_comp_cpu; /* completion CPU */
atomic_t bi_cnt; /* pin count */
struct bio_vec *bi_io_vec; /* the actual vec list */
bio_end_io_t *bi_end_io;
void *bi_private;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif
bio_destructor_t *bi_destructor; /* destructor */
/*
* We can inline a number of vecs at the end of the bio, to avoid
* double allocations for a small number of bio_vecs. This member
* MUST obviously be kept at the very end of the bio.
*/
struct bio_vec bi_inline_vecs[0];
};
/*
* 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 /* bi_phys_segments 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_CPU_AFFINE 8 /* complete bio on same CPU as submitted */
#define BIO_NULL_MAPPED 9 /* contains invalid user pages */
#define BIO_FS_INTEGRITY 10 /* fs owns integrity data, not block layer */
#define BIO_QUIET 11 /* Make BIO Quiet */
#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_NONE ((1UL << BIO_POOL_BITS) - 1)
#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 -- data direction
* If not set, bio is a read from device. If set, it's a write to device.
* bit 1 -- fail fast device errors
* bit 2 -- fail fast transport errors
* bit 3 -- fail fast driver errors
* bit 4 -- rw-ahead when set
* bit 5 -- barrier
* Insert a serialization point in the IO queue, forcing previously
* submitted IO to be completed before this one is issued.
* bit 6 -- synchronous I/O hint.
* bit 7 -- Unplug the device immediately after submitting this bio.
* bit 8 -- metadata request
* Used for tracing to differentiate metadata and data IO. May also
* get some preferential treatment in the IO scheduler
* bit 9 -- discard sectors
* Informs the lower level device that this range of sectors is no longer
* used by the file system and may thus be freed by the device. Used
* for flash based storage.
* Don't want driver retries for any fast fail whatever the reason.
* bit 10 -- Tell the IO scheduler not to wait for more requests after this
one has been submitted, even if it is a SYNC request.
*/
enum bio_rw_flags {
BIO_RW,
BIO_RW_FAILFAST_DEV,
BIO_RW_FAILFAST_TRANSPORT,
BIO_RW_FAILFAST_DRIVER,
/* above flags must match REQ_* */
BIO_RW_AHEAD,
BIO_RW_BARRIER,
BIO_RW_SYNCIO,
BIO_RW_UNPLUG,
BIO_RW_META,
BIO_RW_DISCARD,
BIO_RW_NOIDLE,
};
/*
* First four bits must match between bio->bi_rw and rq->cmd_flags, make
* that explicit here.
*/
#define BIO_RW_RQ_MASK 0xf
static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
{
return (bio->bi_rw & (1 << flag)) != 0;
}
/*
* 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_empty_barrier(bio) (bio_rw_flagged(bio, BIO_RW_BARRIER) && !bio_has_data(bio) && !bio_rw_flagged(bio, BIO_RW_DISCARD))
static inline unsigned int bio_cur_bytes(struct bio *bio)
{
if (bio->bi_vcnt)
return bio_iovec(bio)->bv_len;
else /* dataless requests such as discard */
return bio->bi_size;
}
static inline void *bio_data(struct bio *bio)
{
if (bio->bi_vcnt)
return page_address(bio_page(bio)) + bio_offset(bio);
return NULL;
}
static inline int bio_has_allocated_vec(struct bio *bio)
{
return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
}
/*
* 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)
/* Default implementation of BIOVEC_PHYS_MERGEABLE */
#define __BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
/*
* allow arch override, for eg virtualized architectures (put in asm/io.h)
*/
#ifndef BIOVEC_PHYS_MERGEABLE
#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
#endif
#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, queue_segment_boundary((q)))
#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)
#if defined(CONFIG_BLK_DEV_INTEGRITY)
/*
* bio integrity payload
*/
struct bio_integrity_payload {
struct bio *bip_bio; /* parent bio */
sector_t bip_sector; /* virtual start sector */
void *bip_buf; /* generated integrity data */
bio_end_io_t *bip_end_io; /* saved I/O completion fn */
unsigned int bip_size;
unsigned short bip_slab; /* slab the bip came from */
unsigned short bip_vcnt; /* # of integrity bio_vecs */
unsigned short bip_idx; /* current bip_vec index */
struct work_struct bip_work; /* I/O completion */
struct bio_vec bip_vec[0]; /* embedded bvec array */
};
#endif /* CONFIG_BLK_DEV_INTEGRITY */
/*
* 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;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
struct bio_integrity_payload bip1, bip2;
struct bio_vec iv1, iv2;
#endif
atomic_t cnt;
int error;
};
extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
extern void bio_pair_release(struct bio_pair *dbio);
extern struct bio_set *bioset_create(unsigned int, unsigned int);
extern void bioset_free(struct bio_set *);
extern struct bio *bio_alloc(gfp_t, int);
extern struct bio *bio_kmalloc(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 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 sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
unsigned long, unsigned int, int, gfp_t);
struct sg_iovec;
struct rq_map_data;
extern struct bio *bio_map_user_iov(struct request_queue *,
struct block_device *,
struct sg_iovec *, int, int, gfp_t);
extern void bio_unmap_user(struct bio *);
extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
gfp_t);
extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
gfp_t, int);
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
#endif
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
extern void bio_flush_dcache_pages(struct bio *bi);
#else
static inline void bio_flush_dcache_pages(struct bio *bi)
{
}
#endif
extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
unsigned long, unsigned int, int, gfp_t);
extern struct bio *bio_copy_user_iov(struct request_queue *,
struct rq_map_data *, struct sg_iovec *,
int, int, gfp_t);
extern int bio_uncopy_user(struct bio *);
void zero_fill_bio(struct bio *bio);
extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
/*
* Allow queuer to specify a completion CPU for this bio
*/
static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
{
bio->bi_comp_cpu = cpu;
}
/*
* bio_set is used to allow other portions of the IO system to
* allocate their own private memory pools for bio and iovec structures.
* These memory pools in turn all allocate from the bio_slab
* and the bvec_slabs[].
*/
#define BIO_POOL_SIZE 2
#define BIOVEC_NR_POOLS 6
#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
struct bio_set {
struct kmem_cache *bio_slab;
unsigned int front_pad;
mempool_t *bio_pool;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
mempool_t *bio_integrity_pool;
#endif
mempool_t *bvec_pool;
};
struct biovec_slab {
int nr_vecs;
char *name;
struct kmem_cache *slab;
};
extern struct bio_set *fs_bio_set;
extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly;
/*
* a small number of entries is fine, not going to be performance critical.
* basically we just need to survive
*/
#define BIO_SPLIT_ENTRIES 2
#ifdef CONFIG_HIGHMEM
/*
* remember never ever reenable interrupts between a bvec_kmap_irq and
* bvec_kunmap_irq!
*/
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)
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline int bio_has_data(struct bio *bio)
{
return bio && bio->bi_io_vec != NULL;
}
/*
* BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
*
* A bio_list anchors a singly-linked list of bios chained through the bi_next
* member of the bio. The bio_list also caches the last list member to allow
* fast access to the tail.
*/
struct bio_list {
struct bio *head;
struct bio *tail;
};
static inline int bio_list_empty(const struct bio_list *bl)
{
return bl->head == NULL;
}
static inline void bio_list_init(struct bio_list *bl)
{
bl->head = bl->tail = NULL;
}
#define bio_list_for_each(bio, bl) \
for (bio = (bl)->head; bio; bio = bio->bi_next)
static inline unsigned bio_list_size(const struct bio_list *bl)
{
unsigned sz = 0;
struct bio *bio;
bio_list_for_each(bio, bl)
sz++;
return sz;
}
static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
{
bio->bi_next = NULL;
if (bl->tail)
bl->tail->bi_next = bio;
else
bl->head = bio;
bl->tail = bio;
}
static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
{
bio->bi_next = bl->head;
bl->head = bio;
if (!bl->tail)
bl->tail = bio;
}
static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
{
if (!bl2->head)
return;
if (bl->tail)
bl->tail->bi_next = bl2->head;
else
bl->head = bl2->head;
bl->tail = bl2->tail;
}
static inline void bio_list_merge_head(struct bio_list *bl,
struct bio_list *bl2)
{
if (!bl2->head)
return;
if (bl->head)
bl2->tail->bi_next = bl->head;
else
bl->tail = bl2->tail;
bl->head = bl2->head;
}
static inline struct bio *bio_list_peek(struct bio_list *bl)
{
return bl->head;
}
static inline struct bio *bio_list_pop(struct bio_list *bl)
{
struct bio *bio = bl->head;
if (bio) {
bl->head = bl->head->bi_next;
if (!bl->head)
bl->tail = NULL;
bio->bi_next = NULL;
}
return bio;
}
static inline struct bio *bio_list_get(struct bio_list *bl)
{
struct bio *bio = bl->head;
bl->head = bl->tail = NULL;
return bio;
}
#if defined(CONFIG_BLK_DEV_INTEGRITY)
#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
#define bip_vec(bip) bip_vec_idx(bip, 0)
#define __bip_for_each_vec(bvl, bip, i, start_idx) \
for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
i < (bip)->bip_vcnt; \
bvl++, i++)
#define bip_for_each_vec(bvl, bip, i) \
__bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
#define bio_integrity(bio) (bio->bi_integrity != NULL)
extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
extern void bio_integrity_free(struct bio *, struct bio_set *);
extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
extern int bio_integrity_enabled(struct bio *bio);
extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
extern int bio_integrity_prep(struct bio *);
extern void bio_integrity_endio(struct bio *, int);
extern void bio_integrity_advance(struct bio *, unsigned int);
extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
extern int bioset_integrity_create(struct bio_set *, int);
extern void bioset_integrity_free(struct bio_set *);
extern void bio_integrity_init(void);
#else /* CONFIG_BLK_DEV_INTEGRITY */
#define bio_integrity(a) (0)
#define bioset_integrity_create(a, b) (0)
#define bio_integrity_prep(a) (0)
#define bio_integrity_enabled(a) (0)
#define bio_integrity_clone(a, b, c, d) (0)
#define bioset_integrity_free(a) do { } while (0)
#define bio_integrity_free(a, b) do { } while (0)
#define bio_integrity_endio(a, b) do { } while (0)
#define bio_integrity_advance(a, b) do { } while (0)
#define bio_integrity_trim(a, b, c) do { } while (0)
#define bio_integrity_split(a, b, c) do { } while (0)
#define bio_integrity_set_tag(a, b, c) do { } while (0)
#define bio_integrity_get_tag(a, b, c) do { } while (0)
#define bio_integrity_init(a) do { } while (0)
#endif /* CONFIG_BLK_DEV_INTEGRITY */
#endif /* CONFIG_BLOCK */
#endif /* __LINUX_BIO_H */
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