[linux-block.git] / drivers / isdn / mISDN / timerdev.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * general timer device for using in ISDN stacks
 *
 * Author	Karsten Keil <kkeil@novell.com>
 *
 * Copyright 2008  by Karsten Keil <kkeil@novell.com>
 */

#include <linux/poll.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mISDNif.h>
#include <linux/mutex.h>
#include <linux/sched/signal.h>

#include "core.h"

static DEFINE_MUTEX(mISDN_mutex);
static u_int	*debug;


struct mISDNtimerdev {
	int			next_id;
	struct list_head	pending;
	struct list_head	expired;
	wait_queue_head_t	wait;
	u_int			work;
	spinlock_t		lock; /* protect lists */
};

struct mISDNtimer {
	struct list_head	list;
	struct  mISDNtimerdev	*dev;
	struct timer_list	tl;
	int			id;
};

static int
mISDN_open(struct inode *ino, struct file *filep)
{
	struct mISDNtimerdev	*dev;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
	dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL);
	if (!dev)
		return -ENOMEM;
	dev->next_id = 1;
	INIT_LIST_HEAD(&dev->pending);
	INIT_LIST_HEAD(&dev->expired);
	spin_lock_init(&dev->lock);
	dev->work = 0;
	init_waitqueue_head(&dev->wait);
	filep->private_data = dev;
	return nonseekable_open(ino, filep);
}

static int
mISDN_close(struct inode *ino, struct file *filep)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	struct list_head	*list = &dev->pending;
	struct mISDNtimer	*timer, *next;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);

	spin_lock_irq(&dev->lock);
	while (!list_empty(list)) {
		timer = list_first_entry(list, struct mISDNtimer, list);
		spin_unlock_irq(&dev->lock);
		del_timer_sync(&timer->tl);
		spin_lock_irq(&dev->lock);
		/* it might have been moved to ->expired */
		list_del(&timer->list);
		kfree(timer);
	}
	spin_unlock_irq(&dev->lock);

	list_for_each_entry_safe(timer, next, &dev->expired, list) {
		kfree(timer);
	}
	kfree(dev);
	return 0;
}

static ssize_t
mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	struct list_head *list = &dev->expired;
	struct mISDNtimer	*timer;
	int	ret = 0;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__,
		       filep, buf, (int)count, off);

	if (count < sizeof(int))
		return -ENOSPC;

	spin_lock_irq(&dev->lock);
	while (list_empty(list) && (dev->work == 0)) {
		spin_unlock_irq(&dev->lock);
		if (filep->f_flags & O_NONBLOCK)
			return -EAGAIN;
		wait_event_interruptible(dev->wait, (dev->work ||
						     !list_empty(list)));
		if (signal_pending(current))
			return -ERESTARTSYS;
		spin_lock_irq(&dev->lock);
	}
	if (dev->work)
		dev->work = 0;
	if (!list_empty(list)) {
		timer = list_first_entry(list, struct mISDNtimer, list);
		list_del(&timer->list);
		spin_unlock_irq(&dev->lock);
		if (put_user(timer->id, (int __user *)buf))
			ret = -EFAULT;
		else
			ret = sizeof(int);
		kfree(timer);
	} else {
		spin_unlock_irq(&dev->lock);
	}
	return ret;
}

static __poll_t
mISDN_poll(struct file *filep, poll_table *wait)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	__poll_t		mask = EPOLLERR;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait);
	if (dev) {
		poll_wait(filep, &dev->wait, wait);
		mask = 0;
		if (dev->work || !list_empty(&dev->expired))
			mask |= (EPOLLIN | EPOLLRDNORM);
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__,
			       dev->work, list_empty(&dev->expired));
	}
	return mask;
}

static void
dev_expire_timer(struct timer_list *t)
{
	struct mISDNtimer *timer = from_timer(timer, t, tl);
	u_long			flags;

	spin_lock_irqsave(&timer->dev->lock, flags);
	if (timer->id >= 0)
		list_move_tail(&timer->list, &timer->dev->expired);
	wake_up_interruptible(&timer->dev->wait);
	spin_unlock_irqrestore(&timer->dev->lock, flags);
}

static int
misdn_add_timer(struct mISDNtimerdev *dev, int timeout)
{
	int			id;
	struct mISDNtimer	*timer;

	if (!timeout) {
		dev->work = 1;
		wake_up_interruptible(&dev->wait);
		id = 0;
	} else {
		timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL);
		if (!timer)
			return -ENOMEM;
		timer->dev = dev;
		timer_setup(&timer->tl, dev_expire_timer, 0);
		spin_lock_irq(&dev->lock);
		id = timer->id = dev->next_id++;
		if (dev->next_id < 0)
			dev->next_id = 1;
		list_add_tail(&timer->list, &dev->pending);
		timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
		add_timer(&timer->tl);
		spin_unlock_irq(&dev->lock);
	}
	return id;
}

static int
misdn_del_timer(struct mISDNtimerdev *dev, int id)
{
	struct mISDNtimer	*timer;

	spin_lock_irq(&dev->lock);
	list_for_each_entry(timer, &dev->pending, list) {
		if (timer->id == id) {
			list_del_init(&timer->list);
			timer->id = -1;
			spin_unlock_irq(&dev->lock);
			del_timer_sync(&timer->tl);
			kfree(timer);
			return id;
		}
	}
	spin_unlock_irq(&dev->lock);
	return 0;
}

static long
mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	int			id, tout, ret = 0;


	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__,
		       filep, cmd, arg);
	mutex_lock(&mISDN_mutex);
	switch (cmd) {
	case IMADDTIMER:
		if (get_user(tout, (int __user *)arg)) {
			ret = -EFAULT;
			break;
		}
		id = misdn_add_timer(dev, tout);
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s add %d id %d\n", __func__,
			       tout, id);
		if (id < 0) {
			ret = id;
			break;
		}
		if (put_user(id, (int __user *)arg))
			ret = -EFAULT;
		break;
	case IMDELTIMER:
		if (get_user(id, (int __user *)arg)) {
			ret = -EFAULT;
			break;
		}
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s del id %d\n", __func__, id);
		id = misdn_del_timer(dev, id);
		if (put_user(id, (int __user *)arg))
			ret = -EFAULT;
		break;
	default:
		ret = -EINVAL;
	}
	mutex_unlock(&mISDN_mutex);
	return ret;
}

static const struct file_operations mISDN_fops = {
	.owner		= THIS_MODULE,
	.read		= mISDN_read,
	.poll		= mISDN_poll,
	.unlocked_ioctl	= mISDN_ioctl,
	.open		= mISDN_open,
	.release	= mISDN_close,
	.llseek		= no_llseek,
};

static struct miscdevice mISDNtimer = {
	.minor	= MISC_DYNAMIC_MINOR,
	.name	= "mISDNtimer",
	.fops	= &mISDN_fops,
};

int
mISDN_inittimer(u_int *deb)
{
	int	err;

	debug = deb;
	err = misc_register(&mISDNtimer);
	if (err)
		printk(KERN_WARNING "mISDN: Could not register timer device\n");
	return err;
}

void mISDN_timer_cleanup(void)
{
	misc_deregister(&mISDNtimer);
}
Commit	Line	Data
1802d0be	1	// SPDX-License-Identifier: GPL-2.0-only
1b2b03f8 KK	2	/*
	3	*
	4	* general timer device for using in ISDN stacks
	5	*
	6	* Author Karsten Keil <kkeil@novell.com>
	7	*
	8	* Copyright 2008 by Karsten Keil <kkeil@novell.com>
1b2b03f8 KK	9	*/
	10
	11	#include <linux/poll.h>
	12	#include <linux/vmalloc.h>
5a0e3ad6	13	#include <linux/slab.h>
1b2b03f8 KK	14	#include <linux/timer.h>
	15	#include <linux/miscdevice.h>
	16	#include <linux/module.h>
	17	#include <linux/mISDNif.h>
76a64921	18	#include <linux/mutex.h>
174cd4b1 IM	19	#include <linux/sched/signal.h>
174cd4b1 IM	20
5b834354	21	#include "core.h"
1b2b03f8	22
76a64921	23	static DEFINE_MUTEX(mISDN_mutex);
dfa96ec1	24	static u_int *debug;
1b2b03f8 KK	25
	26
	27	struct mISDNtimerdev {
	28	int next_id;
	29	struct list_head pending;
	30	struct list_head expired;
	31	wait_queue_head_t wait;
	32	u_int work;
	33	spinlock_t lock; /* protect lists */
	34	};
	35
	36	struct mISDNtimer {
	37	struct list_head list;
	38	struct mISDNtimerdev *dev;
	39	struct timer_list tl;
	40	int id;
	41	};
	42
	43	static int
	44	mISDN_open(struct inode ino, struct file filep)
	45	{
	46	struct mISDNtimerdev *dev;
	47
	48	if (*debug & DEBUG_TIMER)
	49	printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
	50	dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL);
	51	if (!dev)
	52	return -ENOMEM;
	53	dev->next_id = 1;
	54	INIT_LIST_HEAD(&dev->pending);
	55	INIT_LIST_HEAD(&dev->expired);
	56	spin_lock_init(&dev->lock);
	57	dev->work = 0;
	58	init_waitqueue_head(&dev->wait);
	59	filep->private_data = dev;
6bff338b	60	return nonseekable_open(ino, filep);
1b2b03f8 KK	61	}
	62
	63	static int
	64	mISDN_close(struct inode ino, struct file filep)
	65	{
	66	struct mISDNtimerdev *dev = filep->private_data;
c08c464d	67	struct list_head *list = &dev->pending;
1b2b03f8 KK	68	struct mISDNtimer timer, next;
	69
	70	if (*debug & DEBUG_TIMER)
	71	printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
c08c464d AV	72
	73	spin_lock_irq(&dev->lock);
	74	while (!list_empty(list)) {
	75	timer = list_first_entry(list, struct mISDNtimer, list);
	76	spin_unlock_irq(&dev->lock);
	77	del_timer_sync(&timer->tl);
	78	spin_lock_irq(&dev->lock);
	79	/* it might have been moved to ->expired */
	80	list_del(&timer->list);
1b2b03f8 KK	81	kfree(timer);
1b2b03f8 KK	82	}
c08c464d AV	83	spin_unlock_irq(&dev->lock);
c08c464d AV	84
1b2b03f8 KK	85	list_for_each_entry_safe(timer, next, &dev->expired, list) {
	86	kfree(timer);
	87	}
	88	kfree(dev);
1b2b03f8 KK	89	return 0;
	90	}
	91
	92	static ssize_t
c46f0a2d	93	mISDN_read(struct file filep, char __user buf, size_t count, loff_t *off)
1b2b03f8 KK	94	{
1b2b03f8 KK	95	struct mISDNtimerdev *dev = filep->private_data;
ebb06be1	96	struct list_head *list = &dev->expired;
1b2b03f8	97	struct mISDNtimer *timer;
1b2b03f8 KK	98	int ret = 0;
	99
	100	if (*debug & DEBUG_TIMER)
	101	printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__,
475be4d8	102	filep, buf, (int)count, off);
1b2b03f8	103
ebb06be1 AV	104	if (count < sizeof(int))
	105	return -ENOSPC;
	106
	107	spin_lock_irq(&dev->lock);
	108	while (list_empty(list) && (dev->work == 0)) {
	109	spin_unlock_irq(&dev->lock);
1b2b03f8 KK	110	if (filep->f_flags & O_NONBLOCK)
	111	return -EAGAIN;
	112	wait_event_interruptible(dev->wait, (dev->work \|\|
ebb06be1	113	!list_empty(list)));
1b2b03f8 KK	114	if (signal_pending(current))
1b2b03f8 KK	115	return -ERESTARTSYS;
ebb06be1	116	spin_lock_irq(&dev->lock);
1b2b03f8	117	}
1b2b03f8 KK	118	if (dev->work)
1b2b03f8 KK	119	dev->work = 0;
ebb06be1 AV	120	if (!list_empty(list)) {
ebb06be1 AV	121	timer = list_first_entry(list, struct mISDNtimer, list);
1b2b03f8	122	list_del(&timer->list);
ebb06be1	123	spin_unlock_irq(&dev->lock);
c46f0a2d	124	if (put_user(timer->id, (int __user *)buf))
1b2b03f8 KK	125	ret = -EFAULT;
	126	else
	127	ret = sizeof(int);
	128	kfree(timer);
ebb06be1 AV	129	} else {
ebb06be1 AV	130	spin_unlock_irq(&dev->lock);
1b2b03f8 KK	131	}
	132	return ret;
	133	}
	134
afc9a42b	135	static __poll_t
1b2b03f8 KK	136	mISDN_poll(struct file filep, poll_table wait)
	137	{
	138	struct mISDNtimerdev *dev = filep->private_data;
a9a08845	139	__poll_t mask = EPOLLERR;
1b2b03f8 KK	140
	141	if (*debug & DEBUG_TIMER)
	142	printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait);
	143	if (dev) {
	144	poll_wait(filep, &dev->wait, wait);
	145	mask = 0;
	146	if (dev->work \|\| !list_empty(&dev->expired))
a9a08845	147	mask \|= (EPOLLIN \| EPOLLRDNORM);
1b2b03f8 KK	148	if (*debug & DEBUG_TIMER)
1b2b03f8 KK	149	printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__,
475be4d8	150	dev->work, list_empty(&dev->expired));
1b2b03f8 KK	151	}
	152	return mask;
	153	}
	154
	155	static void
e313ac12	156	dev_expire_timer(struct timer_list *t)
1b2b03f8	157	{
e313ac12	158	struct mISDNtimer *timer = from_timer(timer, t, tl);
1b2b03f8 KK	159	u_long flags;
	160
	161	spin_lock_irqsave(&timer->dev->lock, flags);
1b108956 AV	162	if (timer->id >= 0)
1b108956 AV	163	list_move_tail(&timer->list, &timer->dev->expired);
1b2b03f8	164	wake_up_interruptible(&timer->dev->wait);
bdcc5bc2	165	spin_unlock_irqrestore(&timer->dev->lock, flags);
1b2b03f8 KK	166	}
	167
	168	static int
	169	misdn_add_timer(struct mISDNtimerdev *dev, int timeout)
	170	{
475be4d8	171	int id;
1b2b03f8 KK	172	struct mISDNtimer *timer;
	173
	174	if (!timeout) {
	175	dev->work = 1;
	176	wake_up_interruptible(&dev->wait);
	177	id = 0;
	178	} else {
	179	timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL);
	180	if (!timer)
	181	return -ENOMEM;
1678ec00	182	timer->dev = dev;
e313ac12	183	timer_setup(&timer->tl, dev_expire_timer, 0);
1678ec00 AV	184	spin_lock_irq(&dev->lock);
1678ec00 AV	185	id = timer->id = dev->next_id++;
1b2b03f8 KK	186	if (dev->next_id < 0)
	187	dev->next_id = 1;
	188	list_add_tail(&timer->list, &dev->pending);
1b2b03f8 KK	189	timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
1b2b03f8 KK	190	add_timer(&timer->tl);
1678ec00	191	spin_unlock_irq(&dev->lock);
1b2b03f8 KK	192	}
	193	return id;
	194	}
	195
	196	static int
	197	misdn_del_timer(struct mISDNtimerdev *dev, int id)
	198	{
1b2b03f8	199	struct mISDNtimer *timer;
1b2b03f8	200
1b108956	201	spin_lock_irq(&dev->lock);
1b2b03f8 KK	202	list_for_each_entry(timer, &dev->pending, list) {
	203	if (timer->id == id) {
	204	list_del_init(&timer->list);
1b108956 AV	205	timer->id = -1;
	206	spin_unlock_irq(&dev->lock);
	207	del_timer_sync(&timer->tl);
1b2b03f8	208	kfree(timer);
1b108956	209	return id;
1b2b03f8 KK	210	}
1b2b03f8 KK	211	}
1b108956 AV	212	spin_unlock_irq(&dev->lock);
1b108956 AV	213	return 0;
1b2b03f8 KK	214	}
1b2b03f8 KK	215
703c631e AB	216	static long
703c631e AB	217	mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
1b2b03f8 KK	218	{
	219	struct mISDNtimerdev *dev = filep->private_data;
	220	int id, tout, ret = 0;
	221
	222
	223	if (*debug & DEBUG_TIMER)
	224	printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__,
475be4d8	225	filep, cmd, arg);
76a64921	226	mutex_lock(&mISDN_mutex);
1b2b03f8 KK	227	switch (cmd) {
	228	case IMADDTIMER:
	229	if (get_user(tout, (int __user *)arg)) {
	230	ret = -EFAULT;
	231	break;
	232	}
	233	id = misdn_add_timer(dev, tout);
	234	if (*debug & DEBUG_TIMER)
	235	printk(KERN_DEBUG "%s add %d id %d\n", __func__,
475be4d8	236	tout, id);
1b2b03f8 KK	237	if (id < 0) {
	238	ret = id;
	239	break;
	240	}
	241	if (put_user(id, (int __user *)arg))
	242	ret = -EFAULT;
	243	break;
	244	case IMDELTIMER:
	245	if (get_user(id, (int __user *)arg)) {
	246	ret = -EFAULT;
	247	break;
	248	}
	249	if (*debug & DEBUG_TIMER)
	250	printk(KERN_DEBUG "%s del id %d\n", __func__, id);
	251	id = misdn_del_timer(dev, id);
	252	if (put_user(id, (int __user *)arg))
	253	ret = -EFAULT;
	254	break;
	255	default:
	256	ret = -EINVAL;
	257	}
76a64921	258	mutex_unlock(&mISDN_mutex);
1b2b03f8 KK	259	return ret;
	260	}
	261
eac74af9	262	static const struct file_operations mISDN_fops = {
89b107ad	263	.owner = THIS_MODULE,
1b2b03f8	264	.read = mISDN_read,
1b2b03f8	265	.poll = mISDN_poll,
703c631e	266	.unlocked_ioctl = mISDN_ioctl,
1b2b03f8 KK	267	.open = mISDN_open,
1b2b03f8 KK	268	.release = mISDN_close,
6038f373	269	.llseek = no_llseek,
1b2b03f8 KK	270	};
	271
	272	static struct miscdevice mISDNtimer = {
	273	.minor = MISC_DYNAMIC_MINOR,
	274	.name = "mISDNtimer",
	275	.fops = &mISDN_fops,
	276	};
	277
	278	int
dfa96ec1	279	mISDN_inittimer(u_int *deb)
1b2b03f8 KK	280	{
	281	int err;
	282
	283	debug = deb;
	284	err = misc_register(&mISDNtimer);
	285	if (err)
	286	printk(KERN_WARNING "mISDN: Could not register timer device\n");
	287	return err;
	288	}
	289
	290	void mISDN_timer_cleanup(void)
	291	{
	292	misc_deregister(&mISDNtimer);
	293	}