/* * spull.c -- the Simple Partitionable Utility * * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files.  The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates.   No warranty is attached; * we cannot take responsibility for errors or fitness for use. * * $Id: spull.c,v 1.17 2001/07/18 22:28:18 rubini Exp $ */#ifndef __KERNEL__#  define __KERNEL__#endif#ifndef MODULE#  define MODULE#endif#include <linux/config.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/kernel.h> /* printk() */#include <linux/malloc.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 <asm/system.h>   /* cli(), *_flags */#define MAJOR_NR spull_major /* force definitions on in blk.h */int spull_major; /* must be declared before including blk.h */#define SPULL_SHIFT 4                         /* max 16 partitions  */#define SPULL_MAXNRDEV 4                      /* max 4 device units */#define DEVICE_NR(device) (MINOR(device)>>SPULL_SHIFT)#define DEVICE_NAME "pd"                      /* name for messaging */#define DEVICE_INTR spull_intrptr         /* pointer to the bottom half */#define DEVICE_NO_RANDOM                  /* no entropy to contribute */#define DEVICE_REQUEST spull_request#define DEVICE_OFF(d) /* do-nothing */#include <linux/blk.h>#include "spull.h"        /* local definitions */#ifdef HAVE_BLKPG_H#include <linux/blkpg.h>  /* blk_ioctl() */#endif/* * Non-prefixed symbols are static. They are meant to be assigned at * load time. Prefixed symbols are not static, so they can be used in * debugging. They are hidden anyways by register_symtab() unless * SPULL_DEBUG is defined. */static int major    = SPULL_MAJOR;static int devs     = SPULL_DEVS;static int rahead   = SPULL_RAHEAD;static int size     = SPULL_SIZE;static int irq      = 0;static int blksize  = SPULL_BLKSIZE;MODULE_PARM(major, "i");MODULE_PARM(devs, "i");MODULE_PARM(rahead, "i");MODULE_PARM(size, "i");MODULE_PARM(blksize, "i");MODULE_PARM(irq, "i");MODULE_AUTHOR("Alessandro Rubini");int spull_devs, spull_rahead, spull_size;int spull_blksize, spull_irq;/* The following items are obtained through kmalloc() in spull_init() */Spull_Dev *spull_devices = NULL;int *spull_sizes = NULL;/* Forwards */int spull_revalidate(kdev_t i_rdev);#ifdef LINUX_24struct block_device_operations spull_bdops;#endif/* * Time for our genhd structure. */struct gendisk spull_gendisk = {    major:              0,              /* Major number assigned later */    major_name:         "pd",           /* Name of the major device */    minor_shift:        SPULL_SHIFT,    /* Shift to get device number */    max_p:              1 << SPULL_SHIFT, /* Number of partitions */#ifdef LINUX_24                             fops:               &spull_bdops,   /* Block dev operations */#endif                                  /* everything else is dynamic */};struct hd_struct *spull_partitions = NULL;/* * Flag used in "irq driven" mode to mark when we have operations * outstanding. */volatile int spull_busy = 0;/* * Open and close */int spull_open (struct inode *inode, struct file *filp){    Spull_Dev *dev; /* device information */    int num = DEVICE_NR(inode->i_rdev);    if (num >= spull_devs) return -ENODEV;    dev = spull_devices + num;    /* kill the timer associated to the device: it might be active */    del_timer(&dev->timer);    spin_lock(&dev->lock);    /*     * If no data area is there, allocate it. Clear its head as     * well to prevent memory corruption due to bad partition info.     */    if (!dev->data) {        dev->data = vmalloc(dev->size);        memset(dev->data,0,2048);    }    if (!dev->data)    {        spin_unlock(&dev->lock);        return -ENOMEM;    }        dev->usage++;    MOD_INC_USE_COUNT;    spin_unlock(&dev->lock);    return 0;          /* success */}int spull_release (struct inode *inode, struct file *filp){    Spull_Dev *dev = spull_devices + DEVICE_NR(inode->i_rdev);    spin_lock(&dev->lock);    dev->usage--;    /*     * If the device is closed for the last time, start a timer     * to release RAM in half a minute. The function and argument     * for the timer have been setup in spull_init()     */    if (!dev->usage) {        dev->timer.expires = jiffies + 60 * HZ;        add_timer(&dev->timer);        /* but flush it right now */        fsync_dev(inode->i_rdev);        invalidate_buffers(inode->i_rdev);    }    MOD_DEC_USE_COUNT;    spin_unlock(&dev->lock);    return 0;}/* * The timer function. As argument it receives the device */void spull_expires(unsigned long data){    Spull_Dev *dev = (Spull_Dev *)data;    spin_lock(&dev->lock);    if (dev->usage || !dev->data) {        spin_unlock(&dev->lock);        printk(KERN_WARNING "spull: timer mismatch for device %i\n",               dev - spull_devices);        return;    }    PDEBUG("freeing device %i\n",dev - spull_devices);    vfree(dev->data);    dev->data=0;    spin_unlock(&dev->lock);    return;}    /* * The ioctl() implementation */int spull_ioctl (struct inode *inode, struct file *filp,                 unsigned int cmd, unsigned long arg){    int err, size;    struct hd_geometry geo;    PDEBUG("ioctl 0x%x 0x%lx\n", cmd, arg);    switch(cmd) {      case BLKGETSIZE:        /* Return the device size, expressed in sectors */        err = ! access_ok (VERIFY_WRITE, arg, sizeof(long));        if (err) return -EFAULT;        size = spull_gendisk.part[MINOR(inode->i_rdev)].nr_sects;	if (copy_to_user((long *) arg, &size, sizeof (long)))	    return -EFAULT;        return 0;      case BLKFLSBUF: /* flush */        if (! capable(CAP_SYS_RAWIO)) return -EACCES; /* only root */        fsync_dev(inode->i_rdev);        invalidate_buffers(inode->i_rdev);        return 0;      case BLKRAGET: /* return the readahead value */        err = ! access_ok(VERIFY_WRITE, arg, sizeof(long));        if (err) return -EFAULT;        PUT_USER(read_ahead[MAJOR(inode->i_rdev)],(long *) arg);        return 0;      case BLKRASET: /* set the readahead value */        if (!capable(CAP_SYS_RAWIO)) return -EACCES;        if (arg > 0xff) return -EINVAL; /* limit it */        read_ahead[MAJOR(inode->i_rdev)] = arg;        return 0;      case BLKRRPART: /* re-read partition table */        return spull_revalidate(inode->i_rdev);      case HDIO_GETGEO:        /*         * get geometry: we have to fake one...  trim the size to a         * multiple of 64 (32k): tell we have 16 sectors, 4 heads,         * whatever cylinders. Tell also that data starts at sector. 4.         */        err = ! access_ok(VERIFY_WRITE, arg, sizeof(geo));        if (err) return -EFAULT;        size = spull_size * blksize / SPULL_HARDSECT;        geo.cylinders = (size & ~0x3f) >> 6;	geo.heads = 4;	geo.sectors = 16;	geo.start = 4;	if (copy_to_user((void *) arg, &geo, sizeof(geo)))	    return -EFAULT;        return 0;      default:        /*         * For ioctls we don't understand, let the block layer handle them.         */        return blk_ioctl(inode->i_rdev, cmd, arg);    }    return -ENOTTY; /* unknown command */}/* * Support for removable devices */int spull_check_change(kdev_t i_rdev){    int minor = DEVICE_NR(i_rdev);    Spull_Dev *dev = spull_devices + minor;    if (minor >= spull_devs) /* paranoid */        return 0;    PDEBUG("check_change for dev %i\n",minor);    if (dev->data)        return 0; /* still valid */    return 1; /* expired */}/* * The file operations */#ifdef LINUX_24struct block_device_operations spull_bdops = {    open:       spull_open,    release:    spull_release,    ioctl:      spull_ioctl,    revalidate: spull_revalidate,    check_media_change: spull_check_change,};#else#ifdef LINUX_20void spull_release_20 (struct inode *inode, struct file *filp){        (void) spull_release (inode, filp);}#define spull_release spull_release_20#endifstruct file_operations spull_bdops = {    read:       block_read,    write:      block_write,    ioctl:      spull_ioctl,    open:       spull_open,    release:    spull_release,    fsync:      block_fsync,    check_media_change: spull_check_change,    revalidate: spull_revalidate};# endif /* LINUX_24 *//* * Note no locks taken out here.  In a worst case scenario, we could drop * a chunk of system memory.  But that should never happen, since validation * happens at open or mount time, when locks are held. */int spull_revalidate(kdev_t i_rdev){    /* first partition, # of partitions */    int part1 = (DEVICE_NR(i_rdev) << SPULL_SHIFT) + 1;    int npart = (1 << SPULL_SHIFT) -1;    /* first clear old partition information */    memset(spull_gendisk.sizes+part1, 0, npart*sizeof(int));    memset(spull_gendisk.part +part1, 0, npart*sizeof(struct hd_struct));    spull_gendisk.part[DEVICE_NR(i_rdev) << SPULL_SHIFT].nr_sects =            spull_size << 1;    /* then fill new info */    printk(KERN_INFO "Spull partition check: (%d) ", DEVICE_NR(i_rdev));    register_disk(&spull_gendisk, i_rdev, SPULL_MAXNRDEV, &spull_bdops,                    spull_size << 1);