/alps/kmm

#include <linux/init.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/types.h>

#include <linux/cdev.h>

#include <linux/fs.h>

#include <linux/slab.h>

#include "mod.h"

#include "dev.h"

#include "debug.h"

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Suren A. Chilingaryan <csa@suren.me>");

MODULE_DESCRIPTION("Kernel Memory Manager - a module to manipulate kernel memory");

MODULE_VERSION("0.0.1");

int kmm_minors = KMM_MINORS;

module_param(kmm_minors, int, S_IRUGO);

static dev_t kmm_devno;			/**< major number */

static kmm_dev_t **kmm_devs = NULL;	/**< per-device context */

static spinlock_t kmm_devs_lock;	/**< lock protecting creation/destruction of devices */

static struct class *kmm_class;		/**< device class */

static void kmm_module_cleanup(void)

{

    int i;

    if (kmm_devs) {

	for (i = 0; i < kmm_minors; i++) {

	    if (kmm_devs[i]) {

		if (kmm_devs[i]->dev)

		    device_destroy(kmm_class, kmm_devs[i]->devno);

		cdev_del(&kmm_devs[i]->cdev);

		kfree(kmm_devs[i]);

	    }

	}

	kfree(kmm_devs);

    }

    if (kmm_class)

    	class_destroy(kmm_class);

    unregister_chrdev_region(kmm_devno, kmm_minors);

}

static int kmm_module_setup_cdev(void)

{

    int i;

    int err = 0;

    dev_t devno;

    kmm_dev_t *dev;

    dev = kmalloc(sizeof(kmm_dev_t), GFP_KERNEL);

    if (!dev) {

	mod_info("Couldn't allocate memory. Device is not created.\n");

	return -ENOMEM;

    }

    cdev_init(&dev->cdev, kmm_get_fops());

    dev->cdev.owner = THIS_MODULE;

    dev->cdev.ops = kmm_get_fops();

    spin_lock(&kmm_devs_lock);

    for (i = 0; i < kmm_minors; i++) {

	if (!kmm_devs[i])

	    break;

    }

    if (i == kmm_minors) {

	mod_info("No free minor numbers left");

	err = -EBUSY;

	goto fail;

    }

    devno = MKDEV(MAJOR(kmm_devno), MINOR(kmm_devno) + i);

    dev->devno = devno;

    err = cdev_add(&dev->cdev, devno, 1);

    if (err) {

	mod_info("Error %d adding device kmm%d", err, i);

	goto fail;

    }

    dev->dev = device_create(kmm_class, NULL, devno, dev, KMM_NODE_FMT, MINOR(kmm_devno) + i);

    if (!dev->dev) {

	mod_info("Error creating /dev/%s%d\n", KMM_NODE, MINOR(kmm_devno) + i);

	goto fail;

    }

    dev_set_drvdata(dev->dev, dev);

    kmm_devs[i] = dev;

    spin_unlock(&kmm_devs_lock);

    mod_info("Device /dev/%s%d added\n", KMM_NODE, MINOR(kmm_devno) + i);

    return 0;

fail:

    spin_unlock(&kmm_devs_lock);

    kfree(dev);

    return err;

}

static int __init kmm_module_init(void)

{

    int err;

    spin_lock_init(&kmm_devs_lock);

    if ((err = alloc_chrdev_region(&kmm_devno, 0, kmm_minors, KMM_NODE))) {

	mod_info("Couldn't allocate chrdev region. Module not loaded.\n");

	goto alloc_chrdev_fail;

    }

    kmm_class = class_create(THIS_MODULE, KMM_NODE);

    if (IS_ERR(kmm_class)) {

	mod_info("No sysfs support. Module not loaded.\n");

	goto fail;

    }

    kmm_devs = kmalloc(kmm_minors * sizeof(kmm_dev_t*), GFP_KERNEL);

    if (!kmm_devs) {

	mod_info("Couldn't allocate memory. Module not loaded.\n");

	err = -ENOMEM;

    }

    memset(kmm_devs, 0, kmm_minors * sizeof(kmm_dev_t*));

    mod_info("Major %d allocated to node '%s'\n", MAJOR(kmm_devno), KMM_NODE);

    err = kmm_module_setup_cdev();

    if (err) goto fail;

    return 0;

fail:

    kmm_module_cleanup();

alloc_chrdev_fail:

    return err;

}

static void __exit kmm_module_exit(void)

{

    kmm_module_cleanup();

}

module_init(kmm_module_init);

module_exit(kmm_module_exit);