--- /dev/null
+/*
+ * 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>
+#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;
+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 */
+ 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_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))
+
+/*
+ * 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)
+/* Platforms may set this to restrict multi-page buffer merging. */
+#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 *bio_alloc(int, int);
+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 *, int);
+
+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 *, int);
+extern void bio_set_pages_dirty(struct bio *bio);
+extern void bio_check_pages_dirty(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 */
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