drivers/isdn/mISDN/timerdev.c

   1 /*
   2  *
   3  * general timer device for using in ISDN stacks
   4  *
   5  * Author       Karsten Keil <[email protected]>
   6  *
   7  * Copyright 2008  by Karsten Keil <[email protected]>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  */
  19
  20 #include <linux/poll.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/slab.h>
  23 #include <linux/timer.h>
  24 #include <linux/miscdevice.h>
  25 #include <linux/module.h>
  26 #include <linux/mISDNif.h>
  27 #include <linux/mutex.h>
  28 #include <linux/sched/signal.h>
  29
  30 #include "core.h"
  31
  32 static DEFINE_MUTEX(mISDN_mutex);
  33 static u_int    *debug;
  34
  35
  36 struct mISDNtimerdev {
  37         int                     next_id;
  38         struct list_head        pending;
  39         struct list_head        expired;
  40         wait_queue_head_t       wait;
  41         u_int                   work;
  42         spinlock_t              lock; /* protect lists */
  43 };
  44
  45 struct mISDNtimer {
  46         struct list_head        list;
  47         struct  mISDNtimerdev   *dev;
  48         struct timer_list       tl;
  49         int                     id;
  50 };
  51
  52 static int
  53 mISDN_open(struct inode *ino, struct file *filep)
  54 {
  55         struct mISDNtimerdev    *dev;
  56
  57         if (*debug & DEBUG_TIMER)
  58                 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
  59         dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL);
  60         if (!dev)
  61                 return -ENOMEM;
  62         dev->next_id = 1;
  63         INIT_LIST_HEAD(&dev->pending);
  64         INIT_LIST_HEAD(&dev->expired);
  65         spin_lock_init(&dev->lock);
  66         dev->work = 0;
  67         init_waitqueue_head(&dev->wait);
  68         filep->private_data = dev;
  69         return nonseekable_open(ino, filep);
  70 }
  71
  72 static int
  73 mISDN_close(struct inode *ino, struct file *filep)
  74 {
  75         struct mISDNtimerdev    *dev = filep->private_data;
  76         struct list_head        *list = &dev->pending;
  77         struct mISDNtimer       *timer, *next;
  78
  79         if (*debug & DEBUG_TIMER)
  80                 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
  81
  82         spin_lock_irq(&dev->lock);
  83         while (!list_empty(list)) {
  84                 timer = list_first_entry(list, struct mISDNtimer, list);
  85                 spin_unlock_irq(&dev->lock);
  86                 del_timer_sync(&timer->tl);
  87                 spin_lock_irq(&dev->lock);
  88                 /* it might have been moved to ->expired */
  89                 list_del(&timer->list);
  90                 kfree(timer);
  91         }
  92         spin_unlock_irq(&dev->lock);
  93
  94         list_for_each_entry_safe(timer, next, &dev->expired, list) {
  95                 kfree(timer);
  96         }
  97         kfree(dev);
  98         return 0;
  99 }
 100
 101 static ssize_t
 102 mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off)
 103 {
 104         struct mISDNtimerdev    *dev = filep->private_data;
 105         struct list_head *list = &dev->expired;
 106         struct mISDNtimer       *timer;
 107         int     ret = 0;
 108
 109         if (*debug & DEBUG_TIMER)
 110                 printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__,
 111                        filep, buf, (int)count, off);
 112
 113         if (count < sizeof(int))
 114                 return -ENOSPC;
 115
 116         spin_lock_irq(&dev->lock);
 117         while (list_empty(list) && (dev->work == 0)) {
 118                 spin_unlock_irq(&dev->lock);
 119                 if (filep->f_flags & O_NONBLOCK)
 120                         return -EAGAIN;
 121                 wait_event_interruptible(dev->wait, (dev->work ||
 122                                                      !list_empty(list)));
 123                 if (signal_pending(current))
 124                         return -ERESTARTSYS;
 125                 spin_lock_irq(&dev->lock);
 126         }
 127         if (dev->work)
 128                 dev->work = 0;
 129         if (!list_empty(list)) {
 130                 timer = list_first_entry(list, struct mISDNtimer, list);
 131                 list_del(&timer->list);
 132                 spin_unlock_irq(&dev->lock);
 133                 if (put_user(timer->id, (int __user *)buf))
 134                         ret = -EFAULT;
 135                 else
 136                         ret = sizeof(int);
 137                 kfree(timer);
 138         } else {
 139                 spin_unlock_irq(&dev->lock);
 140         }
 141         return ret;
 142 }
 143
 144 static __poll_t
 145 mISDN_poll(struct file *filep, poll_table *wait)
 146 {
 147         struct mISDNtimerdev    *dev = filep->private_data;
 148         __poll_t                mask = EPOLLERR;
 149
 150         if (*debug & DEBUG_TIMER)
 151                 printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait);
 152         if (dev) {
 153                 poll_wait(filep, &dev->wait, wait);
 154                 mask = 0;
 155                 if (dev->work || !list_empty(&dev->expired))
 156                         mask |= (EPOLLIN | EPOLLRDNORM);
 157                 if (*debug & DEBUG_TIMER)
 158                         printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__,
 159                                dev->work, list_empty(&dev->expired));
 160         }
 161         return mask;
 162 }
 163
 164 static void
 165 dev_expire_timer(struct timer_list *t)
 166 {
 167         struct mISDNtimer *timer = from_timer(timer, t, tl);
 168         u_long                  flags;
 169
 170         spin_lock_irqsave(&timer->dev->lock, flags);
 171         if (timer->id >= 0)
 172                 list_move_tail(&timer->list, &timer->dev->expired);
 173         spin_unlock_irqrestore(&timer->dev->lock, flags);
 174         wake_up_interruptible(&timer->dev->wait);
 175 }
 176
 177 static int
 178 misdn_add_timer(struct mISDNtimerdev *dev, int timeout)
 179 {
 180         int                     id;
 181         struct mISDNtimer       *timer;
 182
 183         if (!timeout) {
 184                 dev->work = 1;
 185                 wake_up_interruptible(&dev->wait);
 186                 id = 0;
 187         } else {
 188                 timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL);
 189                 if (!timer)
 190                         return -ENOMEM;
 191                 timer->dev = dev;
 192                 timer_setup(&timer->tl, dev_expire_timer, 0);
 193                 spin_lock_irq(&dev->lock);
 194                 id = timer->id = dev->next_id++;
 195                 if (dev->next_id < 0)
 196                         dev->next_id = 1;
 197                 list_add_tail(&timer->list, &dev->pending);
 198                 timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
 199                 add_timer(&timer->tl);
 200                 spin_unlock_irq(&dev->lock);
 201         }
 202         return id;
 203 }
 204
 205 static int
 206 misdn_del_timer(struct mISDNtimerdev *dev, int id)
 207 {
 208         struct mISDNtimer       *timer;
 209
 210         spin_lock_irq(&dev->lock);
 211         list_for_each_entry(timer, &dev->pending, list) {
 212                 if (timer->id == id) {
 213                         list_del_init(&timer->list);
 214                         timer->id = -1;
 215                         spin_unlock_irq(&dev->lock);
 216                         del_timer_sync(&timer->tl);
 217                         kfree(timer);
 218                         return id;
 219                 }
 220         }
 221         spin_unlock_irq(&dev->lock);
 222         return 0;
 223 }
 224
 225 static long
 226 mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 227 {
 228         struct mISDNtimerdev    *dev = filep->private_data;
 229         int                     id, tout, ret = 0;
 230
 231
 232         if (*debug & DEBUG_TIMER)
 233                 printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__,
 234                        filep, cmd, arg);
 235         mutex_lock(&mISDN_mutex);
 236         switch (cmd) {
 237         case IMADDTIMER:
 238                 if (get_user(tout, (int __user *)arg)) {
 239                         ret = -EFAULT;
 240                         break;
 241                 }
 242                 id = misdn_add_timer(dev, tout);
 243                 if (*debug & DEBUG_TIMER)
 244                         printk(KERN_DEBUG "%s add %d id %d\n", __func__,
 245                                tout, id);
 246                 if (id < 0) {
 247                         ret = id;
 248                         break;
 249                 }
 250                 if (put_user(id, (int __user *)arg))
 251                         ret = -EFAULT;
 252                 break;
 253         case IMDELTIMER:
 254                 if (get_user(id, (int __user *)arg)) {
 255                         ret = -EFAULT;
 256                         break;
 257                 }
 258                 if (*debug & DEBUG_TIMER)
 259                         printk(KERN_DEBUG "%s del id %d\n", __func__, id);
 260                 id = misdn_del_timer(dev, id);
 261                 if (put_user(id, (int __user *)arg))
 262                         ret = -EFAULT;
 263                 break;
 264         default:
 265                 ret = -EINVAL;
 266         }
 267         mutex_unlock(&mISDN_mutex);
 268         return ret;
 269 }
 270
 271 static const struct file_operations mISDN_fops = {
 272         .owner          = THIS_MODULE,
 273         .read           = mISDN_read,
 274         .poll           = mISDN_poll,
 275         .unlocked_ioctl = mISDN_ioctl,
 276         .open           = mISDN_open,
 277         .release        = mISDN_close,
 278         .llseek         = no_llseek,
 279 };
 280
 281 static struct miscdevice mISDNtimer = {
 282         .minor  = MISC_DYNAMIC_MINOR,
 283         .name   = "mISDNtimer",
 284         .fops   = &mISDN_fops,
 285 };
 286
 287 int
 288 mISDN_inittimer(u_int *deb)
 289 {
 290         int     err;
 291
 292         debug = deb;
 293         err = misc_register(&mISDNtimer);
 294         if (err)
 295                 printk(KERN_WARNING "mISDN: Could not register timer device\n");
 296         return err;
 297 }
 298
 299 void mISDN_timer_cleanup(void)
 300 {
 301         misc_deregister(&mISDNtimer);
 302 }