blkdev.h

linux 内核源代码

	 * reserved for flush operations
	 */
	unsigned int		ordered, next_ordered, ordseq;
	int			orderr, ordcolor;
	struct request		pre_flush_rq, bar_rq, post_flush_rq;
	struct request		*orig_bar_rq;

	struct mutex		sysfs_lock;

#if defined(CONFIG_BLK_DEV_BSG)
	struct bsg_class_device bsg_dev;
#endif
};

#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	/* read queue has been filled */
#define QUEUE_FLAG_WRITEFULL	4	/* write 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_ELVSWITCH	8	/* don't use elevator, just do FIFO */
#define QUEUE_FLAG_BIDI		9	/* queue supports bidi requests */

enum {
	/*
	 * Hardbarrier is supported with one of the following methods.
	 *
	 * NONE		: hardbarrier unsupported
	 * DRAIN	: ordering by draining is enough
	 * DRAIN_FLUSH	: ordering by draining w/ pre and post flushes
	 * DRAIN_FUA	: ordering by draining w/ pre flush and FUA write
	 * TAG		: ordering by tag is enough
	 * TAG_FLUSH	: ordering by tag w/ pre and post flushes
	 * TAG_FUA	: ordering by tag w/ pre flush and FUA write
	 */
	QUEUE_ORDERED_NONE	= 0x00,
	QUEUE_ORDERED_DRAIN	= 0x01,
	QUEUE_ORDERED_TAG	= 0x02,

	QUEUE_ORDERED_PREFLUSH	= 0x10,
	QUEUE_ORDERED_POSTFLUSH	= 0x20,
	QUEUE_ORDERED_FUA	= 0x40,

	QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
			QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
	QUEUE_ORDERED_DRAIN_FUA	= QUEUE_ORDERED_DRAIN |
			QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
	QUEUE_ORDERED_TAG_FLUSH	= QUEUE_ORDERED_TAG |
			QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
	QUEUE_ORDERED_TAG_FUA	= QUEUE_ORDERED_TAG |
			QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,

	/*
	 * Ordered operation sequence
	 */
	QUEUE_ORDSEQ_STARTED	= 0x01,	/* flushing in progress */
	QUEUE_ORDSEQ_DRAIN	= 0x02,	/* waiting for the queue to be drained */
	QUEUE_ORDSEQ_PREFLUSH	= 0x04,	/* pre-flushing in progress */
	QUEUE_ORDSEQ_BAR	= 0x08,	/* original barrier req in progress */
	QUEUE_ORDSEQ_POSTFLUSH	= 0x10,	/* post-flushing in progress */
	QUEUE_ORDSEQ_DONE	= 0x20,
};

#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)	((q)->ordseq)

#define blk_fs_request(rq)	((rq)->cmd_type == REQ_TYPE_FS)
#define blk_pc_request(rq)	((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
#define blk_special_request(rq)	((rq)->cmd_type == REQ_TYPE_SPECIAL)
#define blk_sense_request(rq)	((rq)->cmd_type == REQ_TYPE_SENSE)

#define blk_noretry_request(rq)	((rq)->cmd_flags & REQ_FAILFAST)
#define blk_rq_started(rq)	((rq)->cmd_flags & REQ_STARTED)

#define blk_account_rq(rq)	(blk_rq_started(rq) && blk_fs_request(rq))

#define blk_pm_suspend_request(rq)	((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
#define blk_pm_resume_request(rq)	((rq)->cmd_type == REQ_TYPE_PM_RESUME)
#define blk_pm_request(rq)	\
	(blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))

#define blk_sorted_rq(rq)	((rq)->cmd_flags & REQ_SORTED)
#define blk_barrier_rq(rq)	((rq)->cmd_flags & REQ_HARDBARRIER)
#define blk_fua_rq(rq)		((rq)->cmd_flags & REQ_FUA)
#define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
#define blk_empty_barrier(rq)	(blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)

#define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)

#define rq_data_dir(rq)		((rq)->cmd_flags & 1)

/*
 * We regard a request as sync, if it's a READ or a SYNC write.
 */
#define rq_is_sync(rq)		(rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
#define rq_is_meta(rq)		((rq)->cmd_flags & REQ_RW_META)

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)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))

/*
 * 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)

/*
 * default timeout for SG_IO if none specified
 */
#define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)

#ifdef CONFIG_BOUNCE
extern int init_emergency_isa_pool(void);
extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
#else
static inline int init_emergency_isa_pool(void)
{
	return 0;
}
static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
{
}
#endif /* CONFIG_MMU */

struct req_iterator {
	int i;
	struct bio *bio;
};

/* This should not be used directly - use rq_for_each_segment */
#define __rq_for_each_bio(_bio, rq)	\
	if ((rq->bio))			\
		for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)

#define rq_for_each_segment(bvl, _rq, _iter)			\
	__rq_for_each_bio(_iter.bio, _rq)			\
		bio_for_each_segment(bvl, _iter.bio, _iter.i)

#define rq_iter_last(rq, _iter)					\
		(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)

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_put_request(struct request_queue *, struct request *);
extern void blk_end_sync_rq(struct request *rq, int error);
extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
extern void blk_requeue_request(struct request_queue *, struct request *);
extern void blk_plug_device(struct request_queue *);
extern int blk_remove_plug(struct request_queue *);
extern void blk_recount_segments(struct request_queue *, struct bio *);
extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
			  struct gendisk *, unsigned int, void __user *);
extern int sg_scsi_ioctl(struct file *, struct request_queue *,
		struct gendisk *, struct scsi_ioctl_command __user *);

/*
 * Temporary export, until SCSI gets fixed up.
 */
extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
			     struct bio *bio);

/*
 * A queue has just exitted congestion.  Note this in the global counter of
 * congested queues, and wake up anyone who was waiting for requests to be
 * put back.
 */
static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
{
	clear_bdi_congested(&q->backing_dev_info, rw);
}

/*
 * A queue has just entered congestion.  Flag that in the queue's VM-visible
 * state flags and increment the global gounter of congested queues.
 */
static inline void blk_set_queue_congested(struct request_queue *q, int rw)
{
	set_bdi_congested(&q->backing_dev_info, rw);
}

extern void blk_start_queue(struct request_queue *q);
extern void blk_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);
extern void __blk_stop_queue(struct request_queue *q);
extern void blk_run_queue(struct request_queue *);
extern void blk_start_queueing(struct request_queue *);
extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
extern int blk_rq_unmap_user(struct bio *);
extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
			       struct sg_iovec *, int, unsigned int);
extern int blk_execute_rq(struct request_queue *, struct gendisk *,
			  struct request *, int);
extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
				  struct request *, int, rq_end_io_fn *);
extern int blk_verify_command(unsigned char *, int);
extern void blk_unplug(struct request_queue *q);

static inline struct request_queue *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 *, int);
extern void end_request(struct request *, int);
extern void end_queued_request(struct request *, int);
extern void end_dequeued_request(struct request *, int);
extern void blk_complete_request(struct request *);

/*
 * 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)
{
	elv_dequeue_request(req->q, req);
}

/*
 * Access functions for manipulating queue properties
 */
extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
					spinlock_t *lock, int node_id);
extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
extern void blk_cleanup_queue(struct request_queue *);
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
extern void blk_queue_bounce_limit(struct request_queue *, u64);
extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
extern void blk_queue_dma_alignment(struct request_queue *, int);
extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
extern int blk_do_ordered(struct request_queue *, struct request **);
extern unsigned blk_ordered_cur_seq(struct request_queue *);
extern unsigned blk_ordered_req_seq(struct request *);
extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);

extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
extern void blk_dump_rq_flags(struct request *, char *);
extern void generic_unplug_device(struct request_queue *);
extern void __generic_unplug_device(struct request_queue *);
extern long nr_blockdev_pages(void);

int blk_get_queue(struct request_queue *);
struct request_queue *blk_alloc_queue(gfp_t);
struct request_queue *blk_alloc_queue_node(gfp_t, int);
extern void blk_put_queue(struct request_queue *);

/*
 * 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)->cmd_flags & REQ_QUEUED)
extern int blk_queue_start_tag(struct request_queue *, struct request *);
extern struct request *blk_queue_find_tag(struct request_queue *, int);
extern void blk_queue_end_tag(struct request_queue *, struct request *);
extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
extern void blk_queue_free_tags(struct request_queue *);
extern int blk_queue_resize_tags(struct request_queue *, int);
extern void blk_queue_invalidate_tags(struct request_queue *);
extern struct blk_queue_tag *blk_init_tags(int);
extern void blk_free_tags(struct blk_queue_tag *);

static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
						int tag)
{
	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
		return NULL;
	return bqt->tag_index[tag];
}

extern int blkdev_issue_flush(struct block_device *, sector_t *);

#define MAX_PHYS_SEGMENTS 128
#define MAX_HW_SEGMENTS 128
#define SAFE_MAX_SECTORS 255
#define BLK_DEF_MAX_SECTORS 1024

#define MAX_SEGMENT_SIZE	65536

#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)

static inline int queue_hardsect_size(struct request_queue *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(struct request_queue *q)
{
	int retval = 511;

	if (q && q->dma_alignment)
		retval = q->dma_alignment;

	return retval;
}

/* 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_work(struct work_struct *work);

#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) "-*")


#else /* CONFIG_BLOCK */
/*
 * stubs for when the block layer is configured out
 */
#define buffer_heads_over_limit 0

static inline long nr_blockdev_pages(void)
{
	return 0;
}

static inline void exit_io_context(void)
{
}

#endif /* CONFIG_BLOCK */

#endif