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Diffstat (limited to 'include/linux/bio.h')
| -rw-r--r-- | include/linux/bio.h | 544 |
1 files changed, 544 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h new file mode 100644 index 00000000..ce33e686 --- /dev/null +++ b/include/linux/bio.h @@ -0,0 +1,544 @@ +/* + * 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> + +/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */ +#include <linux/blk_types.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) + +/* + * 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) + +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; + +/* + * 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 +static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) +{ + return page_address(bvec->bv_page) + bvec->bv_offset; +} + +static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags) +{ + *flags = 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_for_each_integrity_vec(_bvl, _bio, _iter) \ + for_each_bio(_bio) \ + bip_for_each_vec(_bvl, _bio->bi_integrity, _iter) + +#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 */ |