android_kernel_xiaomi_sm8350/include/linux/blkdev.h
152587deb8 [PATCH] fix NMI lockup with CFQ scheduler
The current problem seen is that the queue lock is actually in the
SCSI device structure, so when that structure is freed on device
release, we go boom if the queue tries to access the lock again.

The fix here is to move the lock from the scsi_device to the queue.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-04-16 20:10:09 -05:00

763 lines
22 KiB
C

#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. ->__queue_lock should
* _never_ be used directly, it is queue private. always use
* ->queue_lock.
*/
spinlock_t __queue_lock;
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