cregit-Linux how code gets into the kernel

Release 4.10 drivers/char/misc.c

Directory: drivers/char
/*
 * linux/drivers/char/misc.c
 *
 * Generic misc open routine by Johan Myreen
 *
 * Based on code from Linus
 *
 * Teemu Rantanen's Microsoft Busmouse support and Derrick Cole's
 *   changes incorporated into 0.97pl4
 *   by Peter Cervasio (pete%q106fm.uucp@wupost.wustl.edu) (08SEP92)
 *   See busmouse.c for particulars.
 *
 * Made things a lot mode modular - easy to compile in just one or two
 * of the misc drivers, as they are now completely independent. Linus.
 *
 * Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk>
 *
 * Fixed a failing symbol register to free the device registration
 *              Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96
 *
 * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96
 *
 * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96
 *
 * Handling of mouse minor numbers for kerneld:
 *  Idea by Jacques Gelinas <jack@solucorp.qc.ca>,
 *  adapted by Bjorn Ekwall <bj0rn@blox.se>
 *  corrected by Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 * Changes for kmod (from kerneld):
 *      Cyrus Durgin <cider@speakeasy.org>
 *
 * Added devfs support. Richard Gooch <rgooch@atnf.csiro.au>  10-Jan-1998
 */

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/tty.h>
#include <linux/kmod.h>
#include <linux/gfp.h>

/*
 * Head entry for the doubly linked miscdevice list
 */
static LIST_HEAD(misc_list);
static DEFINE_MUTEX(misc_mtx);

/*
 * Assigned numbers, used for dynamic minors
 */

#define DYNAMIC_MINORS 64 
/* like dynamic majors */
static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);

#ifdef CONFIG_PROC_FS



static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
{
	mutex_lock(&misc_mtx);
	return seq_list_start(&misc_list, *pos);
}


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stephen hemmingerstephen hemminger1753.12%233.33%


pre-gitpre-git825.00%233.33%


pavel emelianovpavel emelianov515.62%116.67%


matthias kaehlckematthias kaehlcke26.25%116.67%


Total32100.00%6100.00%






static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	return seq_list_next(v, &misc_list, pos);
}


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pavel emelianovpavel emelianov516.13%133.33%


pre-gitpre-git13.23%133.33%


Total31100.00%3100.00%






static void misc_seq_stop(struct seq_file *seq, void *v)
{
	mutex_unlock(&misc_mtx);
}


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stephen hemmingerstephen hemminger1990.48%150.00%


matthias kaehlckematthias kaehlcke29.52%150.00%


Total21100.00%2100.00%






static int misc_seq_show(struct seq_file *seq, void *v)
{
	const struct miscdevice *p = list_entry(v, struct miscdevice, list);

	seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");
	return 0;
}



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stephen hemmingerstephen hemminger3054.55%125.00%


pre-gitpre-git1730.91%250.00%


pavel emelianovpavel emelianov814.55%125.00%


Total55100.00%4100.00%




static const struct seq_operations misc_seq_ops = {
	.start = misc_seq_start,
	.next  = misc_seq_next,
	.stop  = misc_seq_stop,
	.show  = misc_seq_show,
};




static int misc_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &misc_seq_ops);
}


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pre-gitpre-git312.00%266.67%


Total25100.00%3100.00%




static const struct file_operations misc_proc_fops = {
	.owner	 = THIS_MODULE,
	.open    = misc_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};
#endif




static int misc_open(struct inode * inode, struct file * file)
{
	int minor = iminor(inode);
	struct miscdevice *c;
	int err = -ENODEV;
	const struct file_operations *new_fops = NULL;

	mutex_lock(&misc_mtx);

	list_for_each_entry(c, &misc_list, list) {
		if (c->minor == minor) {
			new_fops = fops_get(c->fops);
			break;
		}
	}

	if (!new_fops) {
		mutex_unlock(&misc_mtx);
		request_module("char-major-%d-%d", MISC_MAJOR, minor);
		mutex_lock(&misc_mtx);

		list_for_each_entry(c, &misc_list, list) {
			if (c->minor == minor) {
				new_fops = fops_get(c->fops);
				break;
			}
		}
		if (!new_fops)
			goto fail;
	}

	/*
         * Place the miscdevice in the file's
         * private_data so it can be used by the
         * file operations, including f_op->open below
         */
	file->private_data = c;

	err = 0;
	replace_fops(file, new_fops);
	if (file->f_op->open)
		err = file->f_op->open(inode,file);
fail:
	mutex_unlock(&misc_mtx);
	return err;
}


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pre-gitpre-git13870.77%1157.89%


stephen hemmingerstephen hemminger3216.41%15.26%


matthias kaehlckematthias kaehlcke84.10%15.26%


tom van braeckeltom van braeckel73.59%15.26%


al viroal viro52.56%210.53%


mikael petterssonmikael pettersson31.54%15.26%


linus torvaldslinus torvalds10.51%15.26%


arjan van de venarjan van de ven10.51%15.26%


Total195100.00%19100.00%




static struct class *misc_class;


static const struct file_operations misc_fops = {
	.owner		= THIS_MODULE,
	.open		= misc_open,
	.llseek		= noop_llseek,
};

/**
 *      misc_register   -       register a miscellaneous device
 *      @misc: device structure
 *
 *      Register a miscellaneous device with the kernel. If the minor
 *      number is set to %MISC_DYNAMIC_MINOR a minor number is assigned
 *      and placed in the minor field of the structure. For other cases
 *      the minor number requested is used.
 *
 *      The structure passed is linked into the kernel and may not be
 *      destroyed until it has been unregistered. By default, an open()
 *      syscall to the device sets file->private_data to point to the
 *      structure. Drivers don't need open in fops for this.
 *
 *      A zero is returned on success and a negative errno code for
 *      failure.
 */




int misc_register(struct miscdevice * misc)
{
	dev_t dev;
	int err = 0;
	bool is_dynamic = (misc->minor == MISC_DYNAMIC_MINOR);

	INIT_LIST_HEAD(&misc->list);

	mutex_lock(&misc_mtx);

	if (is_dynamic) {
		int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
		if (i >= DYNAMIC_MINORS) {
			err = -EBUSY;
			goto out;
		}
		misc->minor = DYNAMIC_MINORS - i - 1;
		set_bit(i, misc_minors);
	} else {
		struct miscdevice *c;

		list_for_each_entry(c, &misc_list, list) {
			if (c->minor == misc->minor) {
				err = -EBUSY;
				goto out;
			}
		}
	}

	dev = MKDEV(MISC_MAJOR, misc->minor);

	misc->this_device =
		device_create_with_groups(misc_class, misc->parent, dev,
					  misc, misc->groups, "%s", misc->name);
	if (IS_ERR(misc->this_device)) {
		if (is_dynamic) {
			int i = DYNAMIC_MINORS - misc->minor - 1;

			if (i < DYNAMIC_MINORS && i >= 0)
				clear_bit(i, misc_minors);
			misc->minor = MISC_DYNAMIC_MINOR;
		}
		err = PTR_ERR(misc->this_device);
		goto out;
	}

	/*
         * Add it to the front, so that later devices can "override"
         * earlier defaults
         */
	list_add(&misc->list, &misc_list);
 out:
	mutex_unlock(&misc_mtx);
	return err;
}


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thadeu lima de souza cascardothadeu lima de souza cascardo4517.72%28.70%


stephen hemmingerstephen hemminger3614.17%28.70%


dae s. kimdae s. kim3212.60%14.35%


greg kroah-hartmangreg kroah-hartman2710.63%521.74%


vladimir zapolskiyvladimir zapolskiy249.45%14.35%


elad wexlerelad wexler124.72%14.35%


neil hormanneil horman83.15%14.35%


robert loverobert love62.36%14.35%


takashi iwaitakashi iwai51.97%14.35%


matthias kaehlckematthias kaehlcke41.57%14.35%


andrew mortonandrew morton20.79%14.35%


kay sieverskay sievers10.39%14.35%


Total254100.00%23100.00%



/**
 *      misc_deregister - unregister a miscellaneous device
 *      @misc: device to unregister
 *
 *      Unregister a miscellaneous device that was previously
 *      successfully registered with misc_register().
 */




void misc_deregister(struct miscdevice *misc)
{
	int i = DYNAMIC_MINORS - misc->minor - 1;

	if (WARN_ON(list_empty(&misc->list)))
		return;

	mutex_lock(&misc_mtx);
	list_del(&misc->list);
	device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
	if (i < DYNAMIC_MINORS && i >= 0)
		clear_bit(i, misc_minors);
	mutex_unlock(&misc_mtx);
}


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pre-gitpre-git4147.67%323.08%


greg kroah-hartmangreg kroah-hartman1618.60%430.77%


thadeu lima de souza cascardothadeu lima de souza cascardo1112.79%215.38%


stephen hemmingerstephen hemminger1011.63%17.69%


matthias kaehlckematthias kaehlcke44.65%17.69%


akinobu mitaakinobu mita33.49%17.69%


rafael j. wysockirafael j. wysocki11.16%17.69%


Total86100.00%13100.00%




EXPORT_SYMBOL(misc_register);

EXPORT_SYMBOL(misc_deregister);




static char *misc_devnode(struct device *dev, umode_t *mode)
{
	struct miscdevice *c = dev_get_drvdata(dev);

	if (mode && c->mode)
		*mode = c->mode;
	if (c->nodename)
		return kstrdup(c->nodename, GFP_KERNEL);
	return NULL;
}


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al viroal viro11.67%133.33%


Total60100.00%3100.00%






static int __init misc_init(void)
{
	int err;
	struct proc_dir_entry *ret;

	ret = proc_create("misc", 0, NULL, &misc_proc_fops);
	misc_class = class_create(THIS_MODULE, "misc");
	err = PTR_ERR(misc_class);
	if (IS_ERR(misc_class))
		goto fail_remove;

	err = -EIO;
	if (register_chrdev(MISC_MAJOR,"misc",&misc_fops))
		goto fail_printk;
	misc_class->devnode = misc_devnode;
	return 0;

fail_printk:
	printk("unable to get major %d for misc devices\n", MISC_MAJOR);
	class_destroy(misc_class);
fail_remove:
	if (ret)
		remove_proc_entry("misc", NULL);
	return err;
}

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denis v. lunevdenis v. lunev3933.62%15.26%


pre-gitpre-git3429.31%947.37%


greg kroah-hartmangreg kroah-hartman1815.52%315.79%


sudip mukherjeesudip mukherjee119.48%15.26%


kay sieverskay sievers65.17%210.53%


chris wrightchris wright43.45%15.26%


stephen hemmingerstephen hemminger32.59%15.26%


andrew mortonandrew morton10.86%15.26%


Total116100.00%19100.00%




subsys_initcall(misc_init);

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stephen hemmingerstephen hemminger26124.62%34.35%


greg kroah-hartmangreg kroah-hartman726.79%710.14%


kay sieverskay sievers666.23%22.90%


thadeu lima de souza cascardothadeu lima de souza cascardo615.75%22.90%


denis v. lunevdenis v. lunev393.68%11.45%


dae s. kimdae s. kim323.02%11.45%


matthias kaehlckematthias kaehlcke252.36%11.45%


vladimir zapolskiyvladimir zapolskiy242.26%11.45%


pavel emelianovpavel emelianov181.70%11.45%


elad wexlerelad wexler121.13%11.45%


sudip mukherjeesudip mukherjee111.04%11.45%


neil hormanneil horman80.75%11.45%


andrew mortonandrew morton70.66%22.90%


tom van braeckeltom van braeckel70.66%11.45%


al viroal viro60.57%34.35%


robert loverobert love60.57%11.45%


arnd bergmannarnd bergmann50.47%11.45%


takashi iwaitakashi iwai50.47%11.45%


chris wrightchris wright40.38%11.45%


art haasart haas40.38%11.45%


mikael petterssonmikael pettersson30.28%11.45%


akinobu mitaakinobu mita30.28%11.45%


tejun heotejun heo30.28%11.45%


arjan van de venarjan van de ven30.28%22.90%


rafael j. wysockirafael j. wysocki20.19%11.45%


james morrisjames morris10.09%11.45%


linus torvaldslinus torvalds10.09%11.45%


tal shorertal shorer10.09%11.45%


Total1060100.00%69100.00%


Directory: drivers/char



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