1 files changed, 759 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
new file mode 100644
index 0000000000..70ac2860a6
--- /dev/null
+++ b/include/linux/blkdev.h
@@ -0,0 +1,759 @@
+#ifndef _LINUX_BLKDEV_H
+#define _LINUX_BLKDEV_H
+
+#include <linux/config.h>
+#include <linux/major.h>
+#include <linux/genhd.h>
+#include <linux/list.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <linux/pagemap.h>
+#include <linux/backing-dev.h>
+#include <linux/wait.h>
+#include <linux/mempool.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/stringify.h>
+
+#include <asm/scatterlist.h>
+
+struct request_queue;
+typedef struct request_queue request_queue_t;
+struct elevator_queue;
+typedef struct elevator_queue elevator_t;
+struct request_pm_state;
+
+#define BLKDEV_MIN_RQ   4
+#define BLKDEV_MAX_RQ   128     /* Default maximum */
+
+/*
+ * This is the per-process anticipatory I/O scheduler state.
+ */
+struct as_io_context {
+        spinlock_t lock;
+
+        void (*dtor)(struct as_io_context *aic); /* destructor */
+        void (*exit)(struct as_io_context *aic); /* called on task exit */
+
+        unsigned long state;
+        atomic_t nr_queued; /* queued reads & sync writes */
+        atomic_t nr_dispatched; /* number of requests gone to the drivers */
+
+        /* IO History tracking */
+        /* Thinktime */
+        unsigned long last_end_request;
+        unsigned long ttime_total;
+        unsigned long ttime_samples;
+        unsigned long ttime_mean;
+        /* Layout pattern */
+        unsigned int seek_samples;
+        sector_t last_request_pos;
+        u64 seek_total;
+        sector_t seek_mean;
+};
+
+struct cfq_queue;
+struct cfq_io_context {
+        void (*dtor)(struct cfq_io_context *);
+        void (*exit)(struct cfq_io_context *);
+
+        struct io_context *ioc;
+
+        /*
+         * circular list of cfq_io_contexts belonging to a process io context
+         */
+        struct list_head list;
+        struct cfq_queue *cfqq;
+};
+
+/*
+ * This is the per-process I/O subsystem state.  It is refcounted and
+ * kmalloc'ed. Currently all fields are modified in process io context
+ * (apart from the atomic refcount), so require no locking.
+ */
+struct io_context {
+        atomic_t refcount;
+        pid_t pid;
+
+        /*
+         * For request batching
+         */
+        unsigned long last_waited; /* Time last woken after wait for request */
+        int nr_batch_requests;     /* Number of requests left in the batch */
+
+        spinlock_t lock;
+
+        struct as_io_context *aic;
+        struct cfq_io_context *cic;
+};
+
+void put_io_context(struct io_context *ioc);
+void exit_io_context(void);
+struct io_context *get_io_context(int gfp_flags);
+void copy_io_context(struct io_context **pdst, struct io_context **psrc);
+void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
+
+struct request;
+typedef void (rq_end_io_fn)(struct request *);
+
+struct request_list {
+        int count[2];
+        int starved[2];
+        mempool_t *rq_pool;
+        wait_queue_head_t wait[2];
+        wait_queue_head_t drain;
+};
+
+#define BLK_MAX_CDB     16
+
+/*
+ * try to put the fields that are referenced together in the same cacheline
+ */
+struct request {
+        struct list_head queuelist; /* looking for ->queue? you must _not_
+                                     * access it directly, use
+                                     * blkdev_dequeue_request! */
+        unsigned long flags;            /* see REQ_ bits below */
+
+        /* Maintain bio traversal state for part by part I/O submission.
+         * hard_* are block layer internals, no driver should touch them!
+         */
+
+        sector_t sector;                /* next sector to submit */
+        unsigned long nr_sectors;       /* no. of sectors left to submit */
+        /* no. of sectors left to submit in the current segment */
+        unsigned int current_nr_sectors;
+
+        sector_t hard_sector;           /* next sector to complete */
+        unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
+        /* no. of sectors left to complete in the current segment */
+        unsigned int hard_cur_sectors;
+
+        struct bio *bio;
+        struct bio *biotail;
+
+        void *elevator_private;
+
+        int rq_status;  /* should split this into a few status bits */
+        struct gendisk *rq_disk;
+        int errors;
+        unsigned long start_time;
+
+        /* Number of scatter-gather DMA addr+len pairs after
+         * physical address coalescing is performed.
+         */
+        unsigned short nr_phys_segments;
+
+        /* Number of scatter-gather addr+len pairs after
+         * physical and DMA remapping hardware coalescing is performed.
+         * This is the number of scatter-gather entries the driver
+         * will actually have to deal with after DMA mapping is done.
+         */
+        unsigned short nr_hw_segments;
+
+        int tag;
+        char *buffer;
+
+        int ref_count;
+        request_queue_t *q;
+        struct request_list *rl;
+
+        struct completion *waiting;
+        void *special;
+
+        /*
+         * when request is used as a packet command carrier
+         */
+        unsigned int cmd_len;
+        unsigned char cmd[BLK_MAX_CDB];
+
+        unsigned int data_len;
+        void *data;
+
+        unsigned int sense_len;
+        void *sense;
+
+        unsigned int timeout;
+
+        /*
+         * For Power Management requests
+         */
+        struct request_pm_state *pm;
+
+        /*
+         * completion callback. end_io_data should be folded in with waiting
+         */
+        rq_end_io_fn *end_io;
+        void *end_io_data;
+};
+
+/*
+ * first three bits match BIO_RW* bits, important
+ */
+enum rq_flag_bits {
+        __REQ_RW,               /* not set, read. set, write */
+        __REQ_FAILFAST,         /* no low level driver retries */
+        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
+        __REQ_HARDBARRIER,      /* may not be passed by drive either */
+        __REQ_CMD,              /* is a regular fs rw request */
+        __REQ_NOMERGE,          /* don't touch this for merging */
+        __REQ_STARTED,          /* drive already may have started this one */
+        __REQ_DONTPREP,         /* don't call prep for this one */
+        __REQ_QUEUED,           /* uses queueing */
+        /*
+         * for ATA/ATAPI devices
+         */
+        __REQ_PC,               /* packet command (special) */
+        __REQ_BLOCK_PC,         /* queued down pc from block layer */
+        __REQ_SENSE,            /* sense retrival */
+
+        __REQ_FAILED,           /* set if the request failed */
+        __REQ_QUIET,            /* don't worry about errors */
+        __REQ_SPECIAL,          /* driver suplied command */
+        __REQ_DRIVE_CMD,
+        __REQ_DRIVE_TASK,
+        __REQ_DRIVE_TASKFILE,
+        __REQ_PREEMPT,          /* set for "ide_preempt" requests */
+        __REQ_PM_SUSPEND,       /* suspend request */
+        __REQ_PM_RESUME,        /* resume request */
+        __REQ_PM_SHUTDOWN,      /* shutdown request */
+        __REQ_BAR_PREFLUSH,     /* barrier pre-flush done */
+        __REQ_BAR_POSTFLUSH,    /* barrier post-flush */
+        __REQ_BAR_FLUSH,        /* rq is the flush request */
+        __REQ_NR_BITS,          /* stops here */
+};
+
+#define REQ_RW          (1 << __REQ_RW)
+#define REQ_FAILFAST    (1 << __REQ_FAILFAST)
+#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
+#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
+#define REQ_CMD         (1 << __REQ_CMD)
+#define REQ_NOMERGE     (1 << __REQ_NOMERGE)
+#define REQ_STARTED     (1 << __REQ_STARTED)
+#define REQ_DONTPREP    (1 << __REQ_DONTPREP)
+#define REQ_QUEUED      (1 << __REQ_QUEUED)
+#define REQ_PC          (1 << __REQ_PC)
+#define REQ_BLOCK_PC    (1 << __REQ_BLOCK_PC)
+#define REQ_SENSE       (1 << __REQ_SENSE)
+#define REQ_FAILED      (1 << __REQ_FAILED)
+#define REQ_QUIET       (1 << __REQ_QUIET)
+#define REQ_SPECIAL     (1 << __REQ_SPECIAL)
+#define REQ_DRIVE_CMD   (1 << __REQ_DRIVE_CMD)
+#define REQ_DRIVE_TASK  (1 << __REQ_DRIVE_TASK)
+#define REQ_DRIVE_TASKFILE      (1 << __REQ_DRIVE_TASKFILE)
+#define REQ_PREEMPT     (1 << __REQ_PREEMPT)
+#define REQ_PM_SUSPEND  (1 << __REQ_PM_SUSPEND)
+#define REQ_PM_RESUME   (1 << __REQ_PM_RESUME)
+#define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
+#define REQ_BAR_PREFLUSH        (1 << __REQ_BAR_PREFLUSH)
+#define REQ_BAR_POSTFLUSH       (1 << __REQ_BAR_POSTFLUSH)
+#define REQ_BAR_FLUSH   (1 << __REQ_BAR_FLUSH)
+
+/*
+ * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
+ * requests. Some step values could eventually be made generic.
+ */
+struct request_pm_state
+{
+        /* PM state machine step value, currently driver specific */
+        int     pm_step;
+        /* requested PM state value (S1, S2, S3, S4, ...) */
+        u32     pm_state;
+        void*   data;           /* for driver use */
+};
+
+#include <linux/elevator.h>
+
+typedef int (merge_request_fn) (request_queue_t *, struct request *,
+                                struct bio *);
+typedef int (merge_requests_fn) (request_queue_t *, struct request *,
+                                 struct request *);
+typedef void (request_fn_proc) (request_queue_t *q);
+typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
+typedef int (prep_rq_fn) (request_queue_t *, struct request *);
+typedef void (unplug_fn) (request_queue_t *);
+
+struct bio_vec;
+typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
+typedef void (activity_fn) (void *data, int rw);
+typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
+typedef int (prepare_flush_fn) (request_queue_t *, struct request *);
+typedef void (end_flush_fn) (request_queue_t *, struct request *);
+
+enum blk_queue_state {
+        Queue_down,
+        Queue_up,
+};
+
+#define BLK_TAGS_PER_LONG       (sizeof(unsigned long) * 8)
+#define BLK_TAGS_MASK           (BLK_TAGS_PER_LONG - 1)
+
+struct blk_queue_tag {
+        struct request **tag_index;     /* map of busy tags */
+        unsigned long *tag_map;         /* bit map of free/busy tags */
+        struct list_head busy_list;     /* fifo list of busy tags */
+        int busy;                       /* current depth */
+        int max_depth;                  /* what we will send to device */
+        int real_max_depth;             /* what the array can hold */
+        atomic_t refcnt;                /* map can be shared */
+};
+
+struct request_queue
+{
+        /*
+         * Together with queue_head for cacheline sharing
+         */
+        struct list_head        queue_head;
+        struct request          *last_merge;
+        elevator_t              *elevator;
+
+        /*
+         * the queue request freelist, one for reads and one for writes
+         */
+        struct request_list     rq;
+
+        request_fn_proc         *request_fn;
+        merge_request_fn        *back_merge_fn;
+        merge_request_fn        *front_merge_fn;
+        merge_requests_fn       *merge_requests_fn;
+        make_request_fn         *make_request_fn;
+        prep_rq_fn              *prep_rq_fn;
+        unplug_fn               *unplug_fn;
+        merge_bvec_fn           *merge_bvec_fn;
+        activity_fn             *activity_fn;
+        issue_flush_fn          *issue_flush_fn;
+        prepare_flush_fn        *prepare_flush_fn;
+        end_flush_fn            *end_flush_fn;
+
+        /*
+         * Auto-unplugging state
+         */
+        struct timer_list       unplug_timer;
+        int                     unplug_thresh;  /* After this many requests */
+        unsigned long           unplug_delay;   /* After this many jiffies */
+        struct work_struct      unplug_work;
+
+        struct backing_dev_info backing_dev_info;
+
+        /*
+         * The queue owner gets to use this for whatever they like.
+         * ll_rw_blk doesn't touch it.
+         */
+        void                    *queuedata;
+
+        void                    *activity_data;
+
+        /*
+         * queue needs bounce pages for pages above this limit
+         */
+        unsigned long           bounce_pfn;
+        unsigned int            bounce_gfp;
+
+        /*
+         * various queue flags, see QUEUE_* below
+         */
+        unsigned long           queue_flags;
+
+        /*
+         * protects queue structures from reentrancy
+         */
+        spinlock_t              *queue_lock;
+
+        /*
+         * queue kobject
+         */
+        struct kobject kobj;
+
+        /*
+         * queue settings
+         */
+        unsigned long           nr_requests;    /* Max # of requests */
+        unsigned int            nr_congestion_on;
+        unsigned int            nr_congestion_off;
+        unsigned int            nr_batching;
+
+        unsigned short          max_sectors;
+        unsigned short          max_hw_sectors;
+        unsigned short          max_phys_segments;
+        unsigned short          max_hw_segments;
+        unsigned short          hardsect_size;
+        unsigned int            max_segment_size;
+
+        unsigned long           seg_boundary_mask;
+        unsigned int            dma_alignment;
+
+        struct blk_queue_tag    *queue_tags;
+
+        atomic_t                refcnt;
+
+        unsigned int            in_flight;
+
+        /*
+         * sg stuff
+         */
+        unsigned int            sg_timeout;
+        unsigned int            sg_reserved_size;
+
+        struct list_head        drain_list;
+
+        /*
+         * reserved for flush operations
+         */
+        struct request          *flush_rq;
+        unsigned char           ordered;
+};
+
+enum {
+        QUEUE_ORDERED_NONE,
+        QUEUE_ORDERED_TAG,
+        QUEUE_ORDERED_FLUSH,
+};
+
+#define RQ_INACTIVE             (-1)
+#define RQ_ACTIVE               1
+#define RQ_SCSI_BUSY            0xffff
+#define RQ_SCSI_DONE            0xfffe
+#define RQ_SCSI_DISCONNECTING   0xffe0
+
+#define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
+#define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
+#define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
+#define QUEUE_FLAG_READFULL     3       /* write queue has been filled */
+#define QUEUE_FLAG_WRITEFULL    4       /* read queue has been filled */
+#define QUEUE_FLAG_DEAD         5       /* queue being torn down */
+#define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
+#define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
+#define QUEUE_FLAG_DRAIN        8       /* draining queue for sched switch */
+#define QUEUE_FLAG_FLUSH        9       /* doing barrier flush sequence */
+
+#define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
+#define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
+#define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_flushing(q)   test_bit(QUEUE_FLAG_FLUSH, &(q)->queue_flags)
+
+#define blk_fs_request(rq)      ((rq)->flags & REQ_CMD)
+#define blk_pc_request(rq)      ((rq)->flags & REQ_BLOCK_PC)
+#define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
+#define blk_rq_started(rq)      ((rq)->flags & REQ_STARTED)
+
+#define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
+
+#define blk_pm_suspend_request(rq)      ((rq)->flags & REQ_PM_SUSPEND)
+#define blk_pm_resume_request(rq)       ((rq)->flags & REQ_PM_RESUME)
+#define blk_pm_request(rq)      \
+        ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
+
+#define blk_barrier_rq(rq)      ((rq)->flags & REQ_HARDBARRIER)
+#define blk_barrier_preflush(rq)        ((rq)->flags & REQ_BAR_PREFLUSH)
+#define blk_barrier_postflush(rq)       ((rq)->flags & REQ_BAR_POSTFLUSH)
+
+#define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
+
+#define rq_data_dir(rq)         ((rq)->flags & 1)
+
+static inline int blk_queue_full(struct request_queue *q, int rw)
+{
+        if (rw == READ)
+                return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
+        return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+}
+
+static inline void blk_set_queue_full(struct request_queue *q, int rw)
+{
+        if (rw == READ)
+                set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
+        else
+                set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+}
+
+static inline void blk_clear_queue_full(struct request_queue *q, int rw)
+{
+        if (rw == READ)
+                clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
+        else
+                clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+}
+
+
+/*
+ * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
+ * it already be started by driver.
+ */
+#define RQ_NOMERGE_FLAGS        \
+        (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
+#define rq_mergeable(rq)        \
+        (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
+
+/*
+ * noop, requests are automagically marked as active/inactive by I/O
+ * scheduler -- see elv_next_request
+ */
+#define blk_queue_headactive(q, head_active)
+
+/*
+ * q->prep_rq_fn return values
+ */
+#define BLKPREP_OK              0       /* serve it */
+#define BLKPREP_KILL            1       /* fatal error, kill */
+#define BLKPREP_DEFER           2       /* leave on queue */
+
+extern unsigned long blk_max_low_pfn, blk_max_pfn;
+
+/*
+ * standard bounce addresses:
+ *
+ * BLK_BOUNCE_HIGH      : bounce all highmem pages
+ * BLK_BOUNCE_ANY       : don't bounce anything
+ * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
+ */
+#define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
+#define BLK_BOUNCE_ANY          ((u64)blk_max_pfn << PAGE_SHIFT)
+#define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
+
+#ifdef CONFIG_MMU
+extern int init_emergency_isa_pool(void);
+extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
+#else
+static inline int init_emergency_isa_pool(void)
+{
+        return 0;
+}
+static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
+{
+}
+#endif /* CONFIG_MMU */
+
+#define rq_for_each_bio(_bio, rq)       \
+        if ((rq->bio))                  \
+                for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
+
+struct sec_size {
+        unsigned block_size;
+        unsigned block_size_bits;
+};
+
+extern int blk_register_queue(struct gendisk *disk);
+extern void blk_unregister_queue(struct gendisk *disk);
+extern void register_disk(struct gendisk *dev);
+extern void generic_make_request(struct bio *bio);
+extern void blk_put_request(struct request *);
+extern void blk_end_sync_rq(struct request *rq);
+extern void blk_attempt_remerge(request_queue_t *, struct request *);
+extern void __blk_attempt_remerge(request_queue_t *, struct request *);
+extern struct request *blk_get_request(request_queue_t *, int, int);
+extern void blk_insert_request(request_queue_t *, struct request *, int, void *, int);
+extern void blk_requeue_request(request_queue_t *, struct request *);
+extern void blk_plug_device(request_queue_t *);
+extern int blk_remove_plug(request_queue_t *);
+extern void blk_recount_segments(request_queue_t *, struct bio *);
+extern int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
+extern int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
+extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
+extern void blk_start_queue(request_queue_t *q);
+extern void blk_stop_queue(request_queue_t *q);
+extern void blk_sync_queue(struct request_queue *q);
+extern void __blk_stop_queue(request_queue_t *q);
+extern void blk_run_queue(request_queue_t *);
+extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
+extern struct request *blk_rq_map_user(request_queue_t *, int, void __user *, unsigned int);
+extern int blk_rq_unmap_user(struct request *, struct bio *, unsigned int);
+extern int blk_execute_rq(request_queue_t *, struct gendisk *, struct request *);
+
+static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
+{
+        return bdev->bd_disk->queue;
+}
+
+static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
+                                       struct page *page)
+{
+        if (bdi && bdi->unplug_io_fn)
+                bdi->unplug_io_fn(bdi, page);
+}
+
+static inline void blk_run_address_space(struct address_space *mapping)
+{
+        if (mapping)
+                blk_run_backing_dev(mapping->backing_dev_info, NULL);
+}
+
+/*
+ * end_request() and friends. Must be called with the request queue spinlock
+ * acquired. All functions called within end_request() _must_be_ atomic.
+ *
+ * Several drivers define their own end_request and call
+ * end_that_request_first() and end_that_request_last()
+ * for parts of the original function. This prevents
+ * code duplication in drivers.
+ */
+extern int end_that_request_first(struct request *, int, int);
+extern int end_that_request_chunk(struct request *, int, int);
+extern void end_that_request_last(struct request *);
+extern void end_request(struct request *req, int uptodate);
+
+/*
+ * end_that_request_first/chunk() takes an uptodate argument. we account
+ * any value <= as an io error. 0 means -EIO for compatability reasons,
+ * any other < 0 value is the direct error type. An uptodate value of
+ * 1 indicates successful io completion
+ */
+#define end_io_error(uptodate)  (unlikely((uptodate) <= 0))
+
+static inline void blkdev_dequeue_request(struct request *req)
+{
+        BUG_ON(list_empty(&req->queuelist));
+
+        list_del_init(&req->queuelist);
+
+        if (req->rl)
+                elv_remove_request(req->q, req);
+}
+
+/*
+ * Access functions for manipulating queue properties
+ */
+extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
+extern void blk_cleanup_queue(request_queue_t *);
+extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
+extern void blk_queue_bounce_limit(request_queue_t *, u64);
+extern void blk_queue_max_sectors(request_queue_t *, unsigned short);
+extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
+extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
+extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
+extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
+extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
+extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
+extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
+extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
+extern void blk_queue_dma_alignment(request_queue_t *, int);
+extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
+extern void blk_queue_ordered(request_queue_t *, int);
+extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
+extern int blkdev_scsi_issue_flush_fn(request_queue_t *, struct gendisk *, sector_t *);
+extern struct request *blk_start_pre_flush(request_queue_t *,struct request *);
+extern int blk_complete_barrier_rq(request_queue_t *, struct request *, int);
+extern int blk_complete_barrier_rq_locked(request_queue_t *, struct request *, int);
+
+extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
+extern void blk_dump_rq_flags(struct request *, char *);
+extern void generic_unplug_device(request_queue_t *);
+extern void __generic_unplug_device(request_queue_t *);
+extern long nr_blockdev_pages(void);
+extern void blk_wait_queue_drained(request_queue_t *, int);
+extern void blk_finish_queue_drain(request_queue_t *);
+
+int blk_get_queue(request_queue_t *);
+request_queue_t *blk_alloc_queue(int);
+#define blk_put_queue(q) blk_cleanup_queue((q))
+
+/*
+ * tag stuff
+ */
+#define blk_queue_tag_depth(q)          ((q)->queue_tags->busy)
+#define blk_queue_tag_queue(q)          ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
+#define blk_rq_tagged(rq)               ((rq)->flags & REQ_QUEUED)
+extern int blk_queue_start_tag(request_queue_t *, struct request *);
+extern struct request *blk_queue_find_tag(request_queue_t *, int);
+extern void blk_queue_end_tag(request_queue_t *, struct request *);
+extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
+extern void blk_queue_free_tags(request_queue_t *);
+extern int blk_queue_resize_tags(request_queue_t *, int);
+extern void blk_queue_invalidate_tags(request_queue_t *);
+extern long blk_congestion_wait(int rw, long timeout);
+
+extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
+extern int blkdev_issue_flush(struct block_device *, sector_t *);
+
+#define MAX_PHYS_SEGMENTS 128
+#define MAX_HW_SEGMENTS 128
+#define MAX_SECTORS 255
+
+#define MAX_SEGMENT_SIZE        65536
+
+#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
+
+extern void drive_stat_acct(struct request *, int, int);
+
+static inline int queue_hardsect_size(request_queue_t *q)
+{
+        int retval = 512;
+
+        if (q && q->hardsect_size)
+                retval = q->hardsect_size;
+
+        return retval;
+}
+
+static inline int bdev_hardsect_size(struct block_device *bdev)
+{
+        return queue_hardsect_size(bdev_get_queue(bdev));
+}
+
+static inline int queue_dma_alignment(request_queue_t *q)
+{
+        int retval = 511;
+
+        if (q && q->dma_alignment)
+                retval = q->dma_alignment;
+
+        return retval;
+}
+
+static inline int bdev_dma_aligment(struct block_device *bdev)
+{
+        return queue_dma_alignment(bdev_get_queue(bdev));
+}
+
+#define blk_finished_io(nsects) do { } while (0)
+#define blk_started_io(nsects)  do { } while (0)
+
+/* assumes size > 256 */
+static inline unsigned int blksize_bits(unsigned int size)
+{
+        unsigned int bits = 8;
+        do {
+                bits++;
+                size >>= 1;
+        } while (size > 256);
+        return bits;
+}
+
+extern inline unsigned int block_size(struct block_device *bdev)
+{
+        return bdev->bd_block_size;
+}
+
+typedef struct {struct page *v;} Sector;
+
+unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
+
+static inline void put_dev_sector(Sector p)
+{
+        page_cache_release(p.v);
+}
+
+struct work_struct;
+int kblockd_schedule_work(struct work_struct *work);
+void kblockd_flush(void);
+
+#ifdef CONFIG_LBD
+# include <asm/div64.h>
+# define sector_div(a, b) do_div(a, b)
+#else
+# define sector_div(n, b)( \
+{ \
+        int _res; \
+        _res = (n) % (b); \
+        (n) /= (b); \
+        _res; \
+} \
+)
+#endif 
+
+#define MODULE_ALIAS_BLOCKDEV(major,minor) \
+        MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
+#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
+        MODULE_ALIAS("block-major-" __stringify(major) "-*")
+
+
+#endif