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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>
#include <linux/list.h>
struct request_queue;
typedef struct request_queue request_queue_t;
struct elevator_s;
typedef struct elevator_s elevator_t;
/*
* Ok, this is an expanded form so that we can use the same
* request for paging requests.
*/
struct request {
struct list_head queue;
int elevator_sequence;
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 start_time;
unsigned long sector;
unsigned long nr_sectors;
unsigned long hard_sector, hard_nr_sectors;
unsigned int nr_segments;
unsigned int nr_hw_segments;
unsigned long current_nr_sectors;
void * special;
char * buffer;
struct completion * waiting;
struct buffer_head * bh;
struct buffer_head * bhtail;
request_queue_t *q;
};
#include <linux/elevator.h>
typedef int (merge_request_fn) (request_queue_t *q,
struct request *req,
struct buffer_head *bh,
int);
typedef int (merge_requests_fn) (request_queue_t *q,
struct request *req,
struct request *req2,
int);
typedef void (request_fn_proc) (request_queue_t *q);
typedef request_queue_t * (queue_proc) (kdev_t dev);
typedef int (make_request_fn) (request_queue_t *q, int rw, struct buffer_head *bh);
typedef void (plug_device_fn) (request_queue_t *q, kdev_t device);
typedef void (unplug_device_fn) (void *q);
/*
* Default nr free requests per queue, ll_rw_blk will scale it down
* according to available RAM at init time
*/
#define QUEUE_NR_REQUESTS 8192
struct request_list {
unsigned int count;
struct list_head free;
};
struct request_queue
{
/*
* the queue request freelist, one for reads and one for writes
*/
struct request_list rq[2];
/*
* The total number of requests on each queue
*/
int nr_requests;
/*
* Batching threshold for sleep/wakeup decisions
*/
int batch_requests;
/*
* Together with queue_head for cacheline sharing
*/
struct list_head queue_head;
elevator_t elevator;
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;
plug_device_fn * plug_device_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;
/*
* Is meant to protect the queue in the future instead of
* io_request_lock
*/
spinlock_t queue_lock;
/*
* Tasks wait here for free read and write requests
*/
wait_queue_head_t wait_for_requests[2];
};
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 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 generic_make_request(int rw, struct buffer_head * bh);
extern inline request_queue_t *blk_get_queue(kdev_t dev);
extern void blkdev_release_request(struct request *);
/*
* Access functions for manipulating queue properties
*/
extern int blk_grow_request_list(request_queue_t *q, int nr_requests);
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_make_request(request_queue_t *, make_request_fn *);
extern void generic_unplug_device(void *);
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_SEGMENTS 128
#define MAX_SECTORS 255
#define PageAlignSize(size) (((size) + PAGE_SIZE -1) & PAGE_MASK)
#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queue)
#define blkdev_entry_next_request(entry) blkdev_entry_to_request((entry)->next)
#define blkdev_entry_prev_request(entry) blkdev_entry_to_request((entry)->prev)
#define blkdev_next_request(req) blkdev_entry_to_request((req)->queue.next)
#define blkdev_prev_request(req) blkdev_entry_to_request((req)->queue.prev)
extern void drive_stat_acct (kdev_t dev, int rw,
unsigned long nr_sectors, int new_io);
static inline int get_hardsect_size(kdev_t dev)
{
int retval = 512;
int major = MAJOR(dev);
if (hardsect_size[major]) {
int minor = MINOR(dev);
if (hardsect_size[major][minor])
retval = hardsect_size[major][minor];
}
return retval;
}
#define blk_finished_io(nsects) do { } while (0)
#define blk_started_io(nsects) do { } while (0)
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(kdev_t dev)
{
int retval = BLOCK_SIZE;
int major = MAJOR(dev);
if (blksize_size[major]) {
int minor = MINOR(dev);
if (blksize_size[major][minor])
retval = blksize_size[major][minor];
}
return retval;
}
#endif
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