blkdev.h

此工具是arm-linux-GCC交叉编译工具（cross-3.4.4）

	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;
	int			node;

	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 struct request *blk_get_request(request_queue_t *, int, int);
extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
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 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 int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
extern int blk_rq_unmap_user(struct bio *, unsigned int);
extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, unsigned int);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
extern int blk_execute_rq(request_queue_t *, struct gendisk *,
			  struct request *, int);
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_node(request_fn_proc *rfn,
					spinlock_t *lock, int node_id);
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 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 gfp_mask);
request_queue_t *blk_alloc_queue_node(int,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)

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;
}

static 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