/* * 2.5 block I/O model * * Copyright (C) 2001 Jens Axboe * * 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 #include #include #ifdef CONFIG_BLOCK #include #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_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 -- rw-ahead when set * bit 2 -- barrier * Insert a serialization point in the IO queue, forcing previously * submitted IO to be completed before this one is issued. * bit 3 -- synchronous I/O hint: the block layer will unplug immediately * Note that this does NOT indicate that the IO itself is sync, just * that the block layer will not postpone issue of this IO by plugging. * bit 4 -- metadata request * Used for tracing to differentiate metadata and data IO. May also * get some preferential treatment in the IO scheduler * bit 5 -- 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. * bit 6 -- fail fast device errors * bit 7 -- fail fast transport errors * bit 8 -- fail fast driver errors * Don't want driver retries for any fast fail whatever the reason. */ #define BIO_RW 0 /* Must match RW in req flags (blkdev.h) */ #define BIO_RW_AHEAD 1 /* Must match FAILFAST in req flags */ #define BIO_RW_BARRIER 2 #define BIO_RW_SYNC 3 #define BIO_RW_META 4 #define BIO_RW_DISCARD 5 #define BIO_RW_FAILFAST_DEV 6 #define BIO_RW_FAILFAST_TRANSPORT 7 #define BIO_RW_FAILFAST_DRIVER 8 /* * 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_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER)) #define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC)) #define bio_failfast_dev(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_DEV)) #define bio_failfast_transport(bio) \ ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_TRANSPORT)) #define bio_failfast_driver(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST_DRIVER)) #define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD)) #define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META)) #define bio_discard(bio) ((bio)->bi_rw & (1 << BIO_RW_DISCARD)) #define bio_empty_barrier(bio) (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio)) static inline unsigned int bio_cur_sectors(struct bio *bio) { if (bio->bi_vcnt) return bio_iovec(bio)->bv_len >> 9; else /* dataless requests such as discard */ return bio->bi_size >> 9; } 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, (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) #if defined(CONFIG_BLK_DEV_INTEGRITY) /* * bio integrity payload */ struct bio_integrity_payload { struct bio *bip_bio; /* parent bio */ struct bio_vec *bip_vec; /* integrity data vector */ 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_pool; /* pool the ivec 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 */ }; #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); 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 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) /* * 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; } #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 *, 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_slab(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) (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_slab(a) do { } while (0) #endif /* CONFIG_BLK_DEV_INTEGRITY */ #endif /* CONFIG_BLOCK */ #endif /* __LINUX_BIO_H */