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#ifndef _LINUX_BLKDEV_H
#define _LINUX_BLKDEV_H
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/genhd.h>
#include <linux/tqueue.h>
/*
* Ok, this is an expanded form so that we can use the same
* request for paging requests when that is implemented. In
* paging, 'bh' is NULL, and the semaphore is used to wait
* for read/write completion.
*/
struct request {
volatile int rq_status; /* should split this into a few status bits */
#define RQ_INACTIVE (-1)
#define RQ_ACTIVE 1
#define RQ_SCSI_BUSY 0xffff
#define RQ_SCSI_DONE 0xfffe
#define RQ_SCSI_DISCONNECTING 0xffe0
kdev_t rq_dev;
int cmd; /* READ or WRITE */
int errors;
unsigned long sector;
unsigned long nr_sectors;
unsigned int nr_segments;
unsigned int nr_hw_segments;
unsigned long current_nr_sectors;
void * special;
char * buffer;
struct semaphore * sem;
struct buffer_head * bh;
struct buffer_head * bhtail;
struct request * next;
};
typedef struct request_queue request_queue_t;
typedef int (merge_request_fn) (request_queue_t *,
struct request * req,
struct buffer_head *);
typedef int (merge_requests_fn) (request_queue_t *,
struct request * req,
struct request * req2);
typedef void (request_fn_proc) (request_queue_t *);
typedef request_queue_t * (queue_proc) (kdev_t dev);
struct request_queue
{
struct request * current_request;
request_fn_proc * request_fn;
merge_request_fn * merge_fn;
merge_requests_fn * merge_requests_fn;
/*
* The queue owner gets to use this for whatever they like.
* ll_rw_blk doesn't touch it.
*/
void * queuedata;
/*
* This is used to remove the plug when tq_disk runs.
*/
struct tq_struct plug_tq;
/*
* Boolean that indicates whether this queue is plugged or not.
*/
char plugged;
/*
* Boolean that indicates whether current_request is active or
* not.
*/
char head_active;
/*
* Boolean that indicates whether we should use plugging on
* this queue or not.
*/
char use_plug;
};
struct blk_dev_struct {
/*
* queue_proc has to be atomic
*/
request_queue_t request_queue;
queue_proc *queue;
void *data;
};
struct sec_size {
unsigned block_size;
unsigned block_size_bits;
};
/*
* Used to indicate the default queue for drivers that don't bother
* to implement multiple queues. We have this access macro here
* so as to eliminate the need for each and every block device
* driver to know about the internal structure of blk_dev[].
*/
#define BLK_DEFAULT_QUEUE(_MAJOR) &blk_dev[_MAJOR].request_queue
extern struct sec_size * blk_sec[MAX_BLKDEV];
extern struct blk_dev_struct blk_dev[MAX_BLKDEV];
extern wait_queue_head_t wait_for_request;
extern void grok_partitions(struct gendisk *dev, int drive, unsigned minors, long size);
extern void register_disk(struct gendisk *dev, kdev_t first, unsigned minors, struct block_device_operations *ops, long size);
extern void unplug_device(void * data);
extern void make_request(int major,int rw, struct buffer_head * bh);
/*
* Access functions for manipulating queue properties
*/
extern void blk_init_queue(request_queue_t *, request_fn_proc *);
extern void blk_cleanup_queue(request_queue_t *);
extern void blk_queue_headactive(request_queue_t *, int);
extern void blk_queue_pluggable(request_queue_t *, int);
/* md needs this function to remap requests */
extern int md_map (int minor, kdev_t *rdev, unsigned long *rsector, unsigned long size);
extern int md_make_request (int minor, int rw, struct buffer_head * bh);
extern int md_error (kdev_t mddev, kdev_t rdev);
extern int * blk_size[MAX_BLKDEV];
extern int * blksize_size[MAX_BLKDEV];
extern int * hardsect_size[MAX_BLKDEV];
extern int * max_readahead[MAX_BLKDEV];
extern int * max_sectors[MAX_BLKDEV];
extern int * max_segments[MAX_BLKDEV];
#define MAX_SECTORS 128
#define MAX_SEGMENTS MAX_SECTORS
#define PageAlignSize(size) (((size) + PAGE_SIZE -1) & PAGE_MASK)
/* read-ahead in pages.. */
#define MAX_READAHEAD 31
#define MIN_READAHEAD 3
#endif
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