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// 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);
}
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