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Diffstat (limited to 'include/linux/bio.h')
| -rw-r--r-- | include/linux/bio.h | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h new file mode 100644 index 000000000000..038022763f09 --- /dev/null +++ b/include/linux/bio.h @@ -0,0 +1,339 @@ +/* + * 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> + +/* 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 */ + struct bio_set *bi_set; /* memory pools set */ +}; + +/* + * 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 + +/* + * 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(unsigned int __nocast, int); +extern struct bio *bio_alloc_bioset(unsigned int __nocast, int, struct bio_set *); +extern void bio_put(struct bio *); + +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 *, unsigned int __nocast); + +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); +extern void bio_unmap_user(struct bio *); +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. + * Hence the `extern inline'. + */ +extern 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; +} + +extern 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 + +extern 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 */ |