--- /dev/null
+#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>
+#include <linux/mm.h>
+
+#include <asm/io.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, hard_cur_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);
+
+struct request_list {
+ unsigned int count;
+ unsigned int pending[2];
+ struct list_head free;
+};
+
+struct request_queue
+{
+ /*
+ * the queue request freelist, one for reads and one for writes
+ */
+ struct request_list rq;
+
+ /*
+ * The total number of requests on each queue
+ */
+ int nr_requests;
+
+ /*
+ * Batching threshold for sleep/wakeup decisions
+ */
+ int batch_requests;
+
+ /*
+ * The total number of 512byte blocks on each queue
+ */
+ atomic_t nr_sectors;
+
+ /*
+ * Batching threshold for sleep/wakeup decisions
+ */
+ int batch_sectors;
+
+ /*
+ * The max number of 512byte blocks on each queue
+ */
+ int max_queue_sectors;
+
+ /*
+ * 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.
+ */
+ int plugged:1;
+
+ /*
+ * Boolean that indicates whether current_request is active or
+ * not.
+ */
+ int head_active:1;
+
+ /*
+ * Boolean that indicates you will use blk_started_sectors
+ * and blk_finished_sectors in addition to blk_started_io
+ * and blk_finished_io. It enables the throttling code to
+ * help keep the sectors in flight to a reasonable value
+ */
+ int can_throttle:1;
+
+ unsigned long bounce_pfn;
+
+ /*
+ * 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;
+};
+
+#define blk_queue_plugged(q) (q)->plugged
+#define blk_fs_request(rq) ((rq)->cmd == READ || (rq)->cmd == WRITE)
+#define blk_queue_empty(q) list_empty(&(q)->queue_head)
+
+extern inline int rq_data_dir(struct request *rq)
+{
+ if (rq->cmd == READ)
+ return READ;
+ else if (rq->cmd == WRITE)
+ return WRITE;
+ else {
+ BUG();
+ return -1; /* ahem */
+ }
+}
+
+extern unsigned long blk_max_low_pfn, blk_max_pfn;
+
+#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
+#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
+
+extern void blk_queue_bounce_limit(request_queue_t *, u64);
+
+#ifdef CONFIG_HIGHMEM
+extern struct buffer_head *create_bounce(int, struct buffer_head *);
+extern inline struct buffer_head *blk_queue_bounce(request_queue_t *q, int rw,
+ struct buffer_head *bh)
+{
+ struct page *page = bh->b_page;
+
+#ifndef CONFIG_DISCONTIGMEM
+ if (page - mem_map <= q->bounce_pfn)
+#else
+ if ((page - page_zone(page)->zone_mem_map) + (page_zone(page)->zone_start_paddr >> PAGE_SHIFT) <= q->bounce_pfn)
+#endif
+ return bh;
+
+ return create_bounce(rw, bh);
+}
+#else
+#define blk_queue_bounce(q, rw, bh) (bh)
+#endif
+
+#ifdef CONFIG_XEN
+/* Used for buffer merging, where it is imperative we use machine addresses! */
+#define bh_phys(bh) (page_to_bus((bh)->b_page) + bh_offset((bh)))
+#else
+#define bh_phys(bh) (page_to_phys((bh)->b_page) + bh_offset((bh)))
+#endif
+
+#define BH_CONTIG(b1, b2) (bh_phys((b1)) + (b1)->b_size == bh_phys((b2)))
+#define BH_PHYS_4G(b1, b2) ((bh_phys((b1)) | 0xffffffff) == ((bh_phys((b2)) + (b2)->b_size - 1) | 0xffffffff))
+
+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, int max_queue_sectors);
+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_throttle_sectors(request_queue_t *, int);
+extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
+extern void generic_unplug_device(void *);
+extern inline int blk_seg_merge_ok(struct buffer_head *, struct buffer_head *);
+
+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 MAX_QUEUE_SECTORS (4 << (20 - 9)) /* 4 mbytes when full sized */
+#define MAX_NR_REQUESTS 1024 /* 1024k when in 512 units, normally min is 1M in 1k units */
+
+#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;
+}
+
+static inline int blk_oversized_queue(request_queue_t * q)
+{
+ if (q->can_throttle)
+ return atomic_read(&q->nr_sectors) > q->max_queue_sectors;
+ return q->rq.count == 0;
+}
+
+static inline int blk_oversized_queue_reads(request_queue_t * q)
+{
+ if (q->can_throttle)
+ return atomic_read(&q->nr_sectors) > q->max_queue_sectors + q->batch_sectors;
+ return q->rq.count == 0;
+}
+
+static inline int blk_oversized_queue_batch(request_queue_t * q)
+{
+ return atomic_read(&q->nr_sectors) > q->max_queue_sectors - q->batch_sectors;
+}
+
+#define blk_finished_io(nsects) do { } while (0)
+#define blk_started_io(nsects) do { } while (0)
+
+static inline void blk_started_sectors(struct request *rq, int count)
+{
+ request_queue_t *q = rq->q;
+ if (q && q->can_throttle) {
+ atomic_add(count, &q->nr_sectors);
+ if (atomic_read(&q->nr_sectors) < 0) {
+ printk("nr_sectors is %d\n", atomic_read(&q->nr_sectors));
+ BUG();
+ }
+ }
+}
+
+static inline void blk_finished_sectors(struct request *rq, int count)
+{
+ request_queue_t *q = rq->q;
+ if (q && q->can_throttle) {
+ atomic_sub(count, &q->nr_sectors);
+
+ smp_mb();
+ if (q->rq.count >= q->batch_requests && !blk_oversized_queue_batch(q)) {
+ if (waitqueue_active(&q->wait_for_requests))
+ wake_up(&q->wait_for_requests);
+ }
+ if (atomic_read(&q->nr_sectors) < 0) {
+ printk("nr_sectors is %d\n", atomic_read(&q->nr_sectors));
+ BUG();
+ }
+ }
+}
+
+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
projects / xen.git / commitdiff