block device driver from ldd3

放到2.6.36上编译不过了，做了适当的改动。

 

/*
 * Sample disk driver, from the beginning.
 */

//#include <linux/config.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>

#include <linux/sched.h>
#include <linux/kernel.h>    /* printk() */
#include <linux/slab.h>        /* kmalloc() */
#include <linux/fs.h>        /* everything... */
#include <linux/errno.h>    /* error codes */
#include <linux/timer.h>
#include <linux/types.h>    /* size_t */
#include <linux/fcntl.h>    /* O_ACCMODE */
#include <linux/hdreg.h>    /* HDIO_GETGEO */
#include <linux/kdev_t.h>
#include <linux/vmalloc.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>    /* invalidate_bdev */
#include <linux/bio.h>

MODULE_LICENSE("Dual BSD/GPL");

static int sbull_major = 0;
module_param(sbull_major, int, 0);
static int hardsect_size = 512;
module_param(hardsect_size, int, 0);
static int nsectors = 1024;    /* How big the drive is */
module_param(nsectors, int, 0);
static int ndevices = 4;
module_param(ndevices, int, 0);

/*
 * The different "request modes" we can use.
 */
enum {
    RM_SIMPLE  = 0,    /* The extra-simple request function */
    RM_FULL    = 1,    /* The full-blown version */
    RM_NOQUEUE = 2,    /* Use make_request */
};
static int request_mode = RM_SIMPLE;
module_param(request_mode, int, 0);

/*
 * Minor number and partition management.
 */
#define SBULL_MINORS    16
#define MINOR_SHIFT    4
#define DEVNUM(kdevnum)    (MINOR(kdev_t_to_nr(kdevnum)) >> MINOR_SHIFT

/*
 * We can tweak our hardware sector size, but the kernel talks to us
 * in terms of small sectors, always.
 */
#define KERNEL_SECTOR_SIZE    512

/*
 * After this much idle time, the driver will simulate a media change.
 */
#define INVALIDATE_DELAY    30*HZ

/*
 * The internal representation of our device.
 */
struct sbull_dev {
        int size;                       /* Device size in sectors */
        u8 *data;                       /* The data array */
        short users;                    /* How many users */
        short media_change;             /* Flag a media change? */
        spinlock_t lock;                /* For mutual exclusion */
        struct request_queue *queue;    /* The device request queue */
        struct gendisk *gd;             /* The gendisk structure */
        struct timer_list timer;        /* For simulated media changes */
};

static struct sbull_dev *Devices = NULL;

/*
 * Handle an I/O request.
 */
static void sbull_transfer(struct sbull_dev *dev, unsigned long sector,
        unsigned long nsect, char *buffer, int write)
{
    unsigned long offset = sector*KERNEL_SECTOR_SIZE;
    unsigned long nbytes = nsect*KERNEL_SECTOR_SIZE;

    if ((offset + nbytes) > dev->size) {
        printk (KERN_NOTICE "Beyond-end write (%ld %ld)/n", offset, nbytes);
        return;
    }
    if (write)
        memcpy(dev->data + offset, buffer, nbytes);
    else
        memcpy(buffer, dev->data + offset, nbytes);
}

/*
 * The simple form of the request function.
 */
static void sbull_request(struct request_queue *q)
{
    struct request *req;

    while ((req = blk_fetch_request(q)) != NULL) {
        struct sbull_dev *dev = req->rq_disk->private_data;
        if (req->cmd_type != REQ_TYPE_FS) {
            printk (KERN_NOTICE "Skip non-fs request/n");
            __blk_end_request_all(req, 0);
            continue;
        }
    //        printk (KERN_NOTICE "Req dev %d dir %ld sec %ld, nr %d f %lx/n",
    //                dev - Devices, rq_data_dir(req),
    //                req->sector, req->current_nr_sectors,
    //                req->flags);
        sbull_transfer(dev, blk_rq_pos(req), blk_rq_cur_sectors(req),
                req->buffer, rq_data_dir(req));
        __blk_end_request_all(req, 1);
    }
}


/*
 * Transfer a single BIO.
 */
static int sbull_xfer_bio(struct sbull_dev *dev, struct bio *bio)
{
    int i;
    struct bio_vec *bvec;
    sector_t sector = bio->bi_sector;

    /* Do each segment independently. */
    bio_for_each_segment(bvec, bio, i) {
        char *buffer = __bio_kmap_atomic(bio, i, KM_USER0);
        sbull_transfer(dev, sector, bio_cur_bytes(bio)>>9,
                buffer, bio_data_dir(bio) == WRITE);
        sector += bio_cur_bytes(bio)>>9;
        __bio_kunmap_atomic(bio, KM_USER0);
    }
    return 0; /* Always "succeed" */
}

/*
 * Transfer a full request.
 */
static int sbull_xfer_request(struct sbull_dev *dev, struct request *req)
{
    struct bio_vec *biov;
    struct req_iterator riter;
    int nsect = 0;
   
    rq_for_each_segment(biov, req, riter) {
        sbull_xfer_bio(dev, req->bio);
        nsect += req->bio->bi_size/KERNEL_SECTOR_SIZE;
    }
    return nsect;
}



/*
 * Smarter request function that "handles clustering".
 */
static void sbull_full_request(struct request_queue *q)
{
    struct request *req;
    int sectors_xferred;
    struct sbull_dev *dev = q->queuedata;

    while ((req = blk_fetch_request(q)) != NULL) {
        if (req->cmd_type != REQ_TYPE_FS) {
            printk (KERN_NOTICE "Skip non-fs request/n");
            __blk_end_request_cur(req, -EIO);
            continue;
        }
        sectors_xferred = sbull_xfer_request(dev, req);
        __blk_end_request_all(req,0);
    }
}



/*
 * The direct make request version.
 */
static int sbull_make_request(struct request_queue *q, struct bio *bio)
{
    struct sbull_dev *dev = q->queuedata;
    int status;

    status = sbull_xfer_bio(dev, bio);
    bio_endio(bio,  status);
    return 0;
}


/*
 * Open and close.
 */

static int sbull_open(struct block_device *bdev, fmode_t mode)
{
    struct sbull_dev *dev = bdev->bd_disk->private_data;

    del_timer_sync(&dev->timer);
    spin_lock(&dev->lock);
    if (! dev->users)
        check_disk_change(bdev);
    dev->users++;
    spin_unlock(&dev->lock);
    return 0;
}

static int sbull_release(struct gendisk *gd, fmode_t mode)
{
    struct sbull_dev *dev = gd->private_data;

    spin_lock(&dev->lock);
    dev->users--;

    if (!dev->users) {
        dev->timer.expires = jiffies + INVALIDATE_DELAY;
        add_timer(&dev->timer);
    }
    spin_unlock(&dev->lock);

    return 0;
}

/*
 * Look for a (simulated) media change.
 */
int sbull_media_changed(struct gendisk *gd)
{
    struct sbull_dev *dev = gd->private_data;
   
    return dev->media_change;
}

/*
 * Revalidate.  WE DO NOT TAKE THE LOCK HERE, for fear of deadlocking
 * with open.  That needs to be reevaluated.
 */
int sbull_revalidate(struct gendisk *gd)
{
    struct sbull_dev *dev = gd->private_data;
   
    if (dev->media_change) {
        dev->media_change = 0;
        memset (dev->data, 0, dev->size);
    }
    return 0;
}

/*
 * The "invalidate" function runs out of the device timer; it sets
 * a flag to simulate the removal of the media.
 */
void sbull_invalidate(unsigned long ldev)
{
    struct sbull_dev *dev = (struct sbull_dev *) ldev;

    spin_lock(&dev->lock);
    if (dev->users || !dev->data)
        printk (KERN_WARNING "sbull: timer sanity check failed/n");
    else
        dev->media_change = 1;
    spin_unlock(&dev->lock);
}

/*
 * The ioctl() implementation
 */

int sbull_ioctl (struct block_device *bdev, fmode_t mode,
                 unsigned int cmd, unsigned long arg)
{
    long size;
    struct hd_geometry geo;
    struct sbull_dev *dev = bdev->bd_disk->private_data;

    switch(cmd) {
        case HDIO_GETGEO:
            /*
         * Get geometry: since we are a virtual device, we have to make
         * up something plausible.  So we claim 16 sectors, four heads,
         * and calculate the corresponding number of cylinders.  We set the
         * start of data at sector four.
         */
        size = dev->size*(hardsect_size/KERNEL_SECTOR_SIZE);
        geo.cylinders = (size & ~0x3f) >> 6;
        geo.heads = 4;
        geo.sectors = 16;
        geo.start = 4;
        if (copy_to_user((void __user *) arg, &geo, sizeof(geo)))
            return -EFAULT;
        return 0;
    }

    return -ENOTTY; /* unknown command */
}



/*
 * The device operations structure.
 */
static struct block_device_operations sbull_ops = {
    .owner           = THIS_MODULE,
    .open              = sbull_open,
    .release      = sbull_release,
    .media_changed   = sbull_media_changed,
    .revalidate_disk = sbull_revalidate,
    .ioctl             = sbull_ioctl
};


/*
 * Set up our internal device.
 */
static void setup_device(struct sbull_dev *dev, int which)
{
    /*
     * Get some memory.
     */
    memset (dev, 0, sizeof (struct sbull_dev));
    dev->size = nsectors*hardsect_size;
    dev->data = vmalloc(dev->size);
    if (dev->data == NULL) {
        printk (KERN_NOTICE "vmalloc failure./n");
        return;
    }
    spin_lock_init(&dev->lock);
   
    /*
     * The timer which "invalidates" the device.
     */
    init_timer(&dev->timer);
    dev->timer.data = (unsigned long) dev;
    dev->timer.function = sbull_invalidate;
   
    /*
     * The I/O queue, depending on whether we are using our own
     * make_request function or not.
     */
    switch (request_mode) {
        case RM_NOQUEUE:
        dev->queue = blk_alloc_queue(GFP_KERNEL);
        if (dev->queue == NULL)
            goto out_vfree;
        blk_queue_make_request(dev->queue, sbull_make_request);
        break;

        case RM_FULL:
        dev->queue = blk_init_queue(sbull_full_request, &dev->lock);
        if (dev->queue == NULL)
            goto out_vfree;
        break;

        default:
        printk(KERN_NOTICE "Bad request mode %d, using simple/n", request_mode);
            /* fall into.. */
   
        case RM_SIMPLE:
        dev->queue = blk_init_queue(sbull_request, &dev->lock);
        if (dev->queue == NULL)
            goto out_vfree;
        break;
    }
    blk_queue_logical_block_size(dev->queue, hardsect_size);
    dev->queue->queuedata = dev;
    /*
     * And the gendisk structure.
     */
    dev->gd = alloc_disk(SBULL_MINORS);
    if (! dev->gd) {
        printk (KERN_NOTICE "alloc_disk failure/n");
        goto out_vfree;
    }
    dev->gd->major = sbull_major;
    dev->gd->first_minor = which*SBULL_MINORS;
    dev->gd->fops = &sbull_ops;
    dev->gd->queue = dev->queue;
    dev->gd->private_data = dev;
    snprintf (dev->gd->disk_name, 32, "sbull%c", which + 'a');
    set_capacity(dev->gd, nsectors*(hardsect_size/KERNEL_SECTOR_SIZE));
    add_disk(dev->gd);
    return;

  out_vfree:
    if (dev->data)
        vfree(dev->data);
}



static int __init sbull_init(void)
{
    int i;
    /*
     * Get registered.
     */
    sbull_major = register_blkdev(sbull_major, "sbull");
    if (sbull_major <= 0) {
        printk(KERN_WARNING "sbull: unable to get major number/n");
        return -EBUSY;
    }
    /*
     * Allocate the device array, and initialize each one.
     */
    Devices = kmalloc(ndevices*sizeof (struct sbull_dev), GFP_KERNEL);
    if (Devices == NULL)
        goto out_unregister;
    for (i = 0; i < ndevices; i++)
        setup_device(Devices + i, i);
   
    return 0;

  out_unregister:
    unregister_blkdev(sbull_major, "sbd");
    return -ENOMEM;
}

static void sbull_exit(void)
{
    int i;

    for (i = 0; i < ndevices; i++) {
        struct sbull_dev *dev = Devices + i;

        del_timer_sync(&dev->timer);
        if (dev->gd) {
            del_gendisk(dev->gd);
            put_disk(dev->gd);
        }
        if (dev->queue) {
                blk_cleanup_queue(dev->queue);
        }
        if (dev->data)
            vfree(dev->data);
    }
    unregister_blkdev(sbull_major, "sbull");
    kfree(Devices);
}
   
module_init(sbull_init);
module_exit(sbull_exit);

 

最后是加载的脚本

#!/bin/bash

function make_minors {
    minors=16
    part=0
    #echo "/$0 is $0"
    #echo "/$1 is $1"
    #echo "/$2 is $2"
    while [ "$part" -le $minors ]
    do
        minor=$(($part+$2))
        #echo "minor is $minor"
        name=`echo "$1"$part`
        #echo "name is $name"
        mknod $name b $major $minor
        part=$(($part+1))
        #echo "part is $part"
    done
}


# FIXME: This isn't handling minors (partitions) at all.
module="sbull"
device="sbull"
mode="664"
chardevice="sbullr"

# Group: since distributions do it differently, look for wheel or use staff
if grep '^staff:' /etc/group > /dev/null; then
    group="staff"
else
    group="wheel"
fi

# invoke insmod with all arguments we got
# and use a pathname, as newer modutils don't look in . by default
/sbin/insmod -f ./$module.ko $* || exit 1

major=`cat /proc/devices | awk "//$2==/"$module/" {print //$1}"`

# Remove stale nodes and replace them, then give gid and perms

rm -f /dev/${device}[a-d]* /dev/${device}

mknod /dev/${device}a b $major 0
make_minors /dev/${device}a 0
mknod /dev/${device}b b $major 16
make_minors /dev/${device}b 16
mknod /dev/${device}c b $major 32
make_minors /dev/${device}c 32
mknod /dev/${device}d b $major 48
make_minors /dev/${device}d 48
ln -sf ${device}a /dev/${device}
chgrp $group /dev/${device}[a-d]*
chmod $mode  /dev/${device}[a-d]*