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#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_s;
typedef struct elevator_s 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;
};
/*
* 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 */
struct as_io_context *aic;
};
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_list {
int count[2];
mempool_t *rq_pool;
wait_queue_head_t wait[2];
};
#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;
/* no. of segments left to submit in the current bio */
unsigned short nr_cbio_segments;
/* no. of sectors left to submit in the current bio */
unsigned long nr_cbio_sectors;
struct bio *cbio; /* next bio to submit */
struct bio *bio; /* next unfinished bio to complete */
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;
};
/*
* 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_IDETAPE_PC1, /* packet command (first stage) */
__REQ_IDETAPE_PC2, /* packet command (second stage) */
__REQ_IDETAPE_READ,
__REQ_IDETAPE_WRITE,
__REQ_IDETAPE_READ_BUFFER,
__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_IDETAPE_PC1 (1 << __REQ_IDETAPE_PC1)
#define REQ_IDETAPE_PC2 (1 << __REQ_IDETAPE_PC2)
#define REQ_IDETAPE_READ (1 << __REQ_IDETAPE_READ)
#define REQ_IDETAPE_WRITE (1 << __REQ_IDETAPE_WRITE)
#define REQ_IDETAPE_READ_BUFFER (1 << __REQ_IDETAPE_READ_BUFFER)
/*
* 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) (void *q);
struct bio_vec;
typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
typedef void (activity_fn) (void *data, int rw);
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;
/*
* 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;
int bounce_gfp;
struct list_head plug_list;
/*
* 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 short max_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;
/*
* sg stuff
*/
unsigned int sg_timeout;
unsigned int sg_reserved_size;
};
#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 blk_queue_plugged(q) !list_empty(&(q)->plug_list)
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(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_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 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)
/* current index into bio being processed for submission */
#define blk_rq_idx(rq) ((rq)->cbio->bi_vcnt - (rq)->nr_cbio_segments)
/* current bio vector being processed */
#define blk_rq_vec(rq) (bio_iovec_idx((rq)->cbio, blk_rq_idx(rq)))
/* current offset with respect to start of the segment being submitted */
#define blk_rq_offset(rq) \
(((rq)->hard_cur_sectors - (rq)->current_nr_sectors) << 9)
/*
* temporarily mapping a (possible) highmem bio (typically for PIO transfer)
*/
/* Assumes rq->cbio != NULL */
static inline char * rq_map_buffer(struct request *rq, unsigned long *flags)
{
return (__bio_kmap_irq(rq->cbio, blk_rq_idx(rq), flags)
+ blk_rq_offset(rq));
}
static inline void rq_unmap_buffer(char *buffer, unsigned long *flags)
{
__bio_kunmap_irq(buffer, flags);
}
/*
* 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_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_put_request(struct request *);
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 inline int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
extern inline int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
extern int scsi_cmd_ioctl(struct block_device *, unsigned int, unsigned long);
extern void blk_start_queue(request_queue_t *q);
extern void blk_stop_queue(request_queue_t *q);
extern void __blk_stop_queue(request_queue_t *q);
extern void blk_run_queue(request_queue_t *q);
extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
{
return bdev->bd_disk->queue;
}
/*
* 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 int process_that_request_first(struct request *, unsigned int);
extern void end_request(struct request *req, int uptodate);
static inline void blkdev_dequeue_request(struct request *req)
{
BUG_ON(list_empty(&req->queuelist));
list_del_init(&req->queuelist);
if (req->q)
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 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(void *);
extern long nr_blockdev_pages(void);
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 void blk_congestion_wait(int rw, long timeout);
extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
extern void blk_rq_prep_restart(struct request *);
#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