releases/2.6.23.15/input-evdev-implement-proper-locking.patch

   1 From 6addb1d6de1968b84852f54561cc9a999909b5a9 Mon Sep 17 00:00:00 2001
   2 From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
   3 Date: Thu, 30 Aug 2007 00:22:18 -0400
   4 Subject: Input: evdev - implement proper locking
   5
   6 From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
   7
   8 patch 6addb1d6de1968b84852f54561cc9a999909b5a9 in mainline.
   9
  10 Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
  11 Cc: Al Viro <viro@ZenIV.linux.org.uk>
  12 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  13
  14 ---
  15  drivers/input/evdev.c |  719 +++++++++++++++++++++++++++++++++-----------------
  16  1 file changed, 476 insertions(+), 243 deletions(-)
  17
  18 --- a/drivers/input/evdev.c
  19 +++ b/drivers/input/evdev.c
  20 @@ -30,6 +30,8 @@ struct evdev {
  21         wait_queue_head_t wait;
  22         struct evdev_client *grab;
  23         struct list_head client_list;
  24 +       spinlock_t client_lock; /* protects client_list */
  25 +       struct mutex mutex;
  26         struct device dev;
  27  };
  28
  29 @@ -37,39 +39,53 @@ struct evdev_client {
  30         struct input_event buffer[EVDEV_BUFFER_SIZE];
  31         int head;
  32         int tail;
  33 +       spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  34         struct fasync_struct *fasync;
  35         struct evdev *evdev;
  36         struct list_head node;
  37  };
  38
  39  static struct evdev *evdev_table[EVDEV_MINORS];
  40 +static DEFINE_MUTEX(evdev_table_mutex);
  41
  42 -static void evdev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
  43 +static void evdev_pass_event(struct evdev_client *client,
  44 +                            struct input_event *event)
  45 +{
  46 +       /*
  47 +        * Interrupts are disabled, just acquire the lock
  48 +        */
  49 +       spin_lock(&client->buffer_lock);
  50 +       client->buffer[client->head++] = *event;
  51 +       client->head &= EVDEV_BUFFER_SIZE - 1;
  52 +       spin_unlock(&client->buffer_lock);
  53 +
  54 +       kill_fasync(&client->fasync, SIGIO, POLL_IN);
  55 +}
  56 +
  57 +/*
  58 + * Pass incoming event to all connected clients. Note that we are
  59 + * caleld under a spinlock with interrupts off so we don't need
  60 + * to use rcu_read_lock() here. Writers will be using syncronize_sched()
  61 + * instead of synchrnoize_rcu().
  62 + */
  63 +static void evdev_event(struct input_handle *handle,
  64 +                       unsigned int type, unsigned int code, int value)
  65  {
  66         struct evdev *evdev = handle->private;
  67         struct evdev_client *client;
  68 +       struct input_event event;
  69
  70 -       if (evdev->grab) {
  71 -               client = evdev->grab;
  72 -
  73 -               do_gettimeofday(&client->buffer[client->head].time);
  74 -               client->buffer[client->head].type = type;
  75 -               client->buffer[client->head].code = code;
  76 -               client->buffer[client->head].value = value;
  77 -               client->head = (client->head + 1) & (EVDEV_BUFFER_SIZE - 1);
  78 -
  79 -               kill_fasync(&client->fasync, SIGIO, POLL_IN);
  80 -       } else
  81 -               list_for_each_entry(client, &evdev->client_list, node) {
  82 -
  83 -                       do_gettimeofday(&client->buffer[client->head].time);
  84 -                       client->buffer[client->head].type = type;
  85 -                       client->buffer[client->head].code = code;
  86 -                       client->buffer[client->head].value = value;
  87 -                       client->head = (client->head + 1) & (EVDEV_BUFFER_SIZE - 1);
  88 -
  89 -                       kill_fasync(&client->fasync, SIGIO, POLL_IN);
  90 -               }
  91 +       do_gettimeofday(&event.time);
  92 +       event.type = type;
  93 +       event.code = code;
  94 +       event.value = value;
  95 +
  96 +       client = rcu_dereference(evdev->grab);
  97 +       if (client)
  98 +               evdev_pass_event(client, &event);
  99 +       else
 100 +               list_for_each_entry_rcu(client, &evdev->client_list, node)
 101 +                       evdev_pass_event(client, &event);
 102
 103         wake_up_interruptible(&evdev->wait);
 104  }
 105 @@ -88,38 +104,142 @@ static int evdev_flush(struct file *file
 106  {
 107         struct evdev_client *client = file->private_data;
 108         struct evdev *evdev = client->evdev;
 109 +       int retval;
 110 +
 111 +       retval = mutex_lock_interruptible(&evdev->mutex);
 112 +       if (retval)
 113 +               return retval;
 114
 115         if (!evdev->exist)
 116 -               return -ENODEV;
 117 +               retval = -ENODEV;
 118 +       else
 119 +               retval = input_flush_device(&evdev->handle, file);
 120
 121 -       return input_flush_device(&evdev->handle, file);
 122 +       mutex_unlock(&evdev->mutex);
 123 +       return retval;
 124  }
 125
 126  static void evdev_free(struct device *dev)
 127  {
 128         struct evdev *evdev = container_of(dev, struct evdev, dev);
 129
 130 -       evdev_table[evdev->minor] = NULL;
 131         kfree(evdev);
 132  }
 133
 134 +/*
 135 + * Grabs an event device (along with underlying input device).
 136 + * This function is called with evdev->mutex taken.
 137 + */
 138 +static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 139 +{
 140 +       int error;
 141 +
 142 +       if (evdev->grab)
 143 +               return -EBUSY;
 144 +
 145 +       error = input_grab_device(&evdev->handle);
 146 +       if (error)
 147 +               return error;
 148 +
 149 +       rcu_assign_pointer(evdev->grab, client);
 150 +       /*
 151 +        * We don't use synchronize_rcu() here because read-side
 152 +        * critical section is protected by a spinlock instead
 153 +        * of rcu_read_lock().
 154 +        */
 155 +       synchronize_sched();
 156 +
 157 +       return 0;
 158 +}
 159 +
 160 +static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 161 +{
 162 +       if (evdev->grab != client)
 163 +               return  -EINVAL;
 164 +
 165 +       rcu_assign_pointer(evdev->grab, NULL);
 166 +       synchronize_sched();
 167 +       input_release_device(&evdev->handle);
 168 +
 169 +       return 0;
 170 +}
 171 +
 172 +static void evdev_attach_client(struct evdev *evdev,
 173 +                               struct evdev_client *client)
 174 +{
 175 +       spin_lock(&evdev->client_lock);
 176 +       list_add_tail_rcu(&client->node, &evdev->client_list);
 177 +       spin_unlock(&evdev->client_lock);
 178 +       synchronize_sched();
 179 +}
 180 +
 181 +static void evdev_detach_client(struct evdev *evdev,
 182 +                               struct evdev_client *client)
 183 +{
 184 +       spin_lock(&evdev->client_lock);
 185 +       list_del_rcu(&client->node);
 186 +       spin_unlock(&evdev->client_lock);
 187 +       synchronize_sched();
 188 +}
 189 +
 190 +static int evdev_open_device(struct evdev *evdev)
 191 +{
 192 +       int retval;
 193 +
 194 +       retval = mutex_lock_interruptible(&evdev->mutex);
 195 +       if (retval)
 196 +               return retval;
 197 +
 198 +       if (!evdev->exist)
 199 +               retval = -ENODEV;
 200 +       else if (!evdev->open++)
 201 +               retval = input_open_device(&evdev->handle);
 202 +
 203 +       mutex_unlock(&evdev->mutex);
 204 +       return retval;
 205 +}
 206 +
 207 +static void evdev_close_device(struct evdev *evdev)
 208 +{
 209 +       mutex_lock(&evdev->mutex);
 210 +
 211 +       if (evdev->exist && !--evdev->open)
 212 +               input_close_device(&evdev->handle);
 213 +
 214 +       mutex_unlock(&evdev->mutex);
 215 +}
 216 +
 217 +/*
 218 + * Wake up users waiting for IO so they can disconnect from
 219 + * dead device.
 220 + */
 221 +static void evdev_hangup(struct evdev *evdev)
 222 +{
 223 +       struct evdev_client *client;
 224 +
 225 +       spin_lock(&evdev->client_lock);
 226 +       list_for_each_entry(client, &evdev->client_list, node)
 227 +               kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 228 +       spin_unlock(&evdev->client_lock);
 229 +
 230 +       wake_up_interruptible(&evdev->wait);
 231 +}
 232 +
 233  static int evdev_release(struct inode *inode, struct file *file)
 234  {
 235         struct evdev_client *client = file->private_data;
 236         struct evdev *evdev = client->evdev;
 237
 238 -       if (evdev->grab == client) {
 239 -               input_release_device(&evdev->handle);
 240 -               evdev->grab = NULL;
 241 -       }
 242 +       mutex_lock(&evdev->mutex);
 243 +       if (evdev->grab == client)
 244 +               evdev_ungrab(evdev, client);
 245 +       mutex_unlock(&evdev->mutex);
 246
 247         evdev_fasync(-1, file, 0);
 248 -       list_del(&client->node);
 249 +       evdev_detach_client(evdev, client);
 250         kfree(client);
 251
 252 -       if (!--evdev->open && evdev->exist)
 253 -               input_close_device(&evdev->handle);
 254 -
 255 +       evdev_close_device(evdev);
 256         put_device(&evdev->dev);
 257
 258         return 0;
 259 @@ -127,41 +247,44 @@ static int evdev_release(struct inode *i
 260
 261  static int evdev_open(struct inode *inode, struct file *file)
 262  {
 263 -       struct evdev_client *client;
 264         struct evdev *evdev;
 265 +       struct evdev_client *client;
 266         int i = iminor(inode) - EVDEV_MINOR_BASE;
 267         int error;
 268
 269         if (i >= EVDEV_MINORS)
 270                 return -ENODEV;
 271
 272 +       error = mutex_lock_interruptible(&evdev_table_mutex);
 273 +       if (error)
 274 +               return error;
 275         evdev = evdev_table[i];
 276 +       if (evdev)
 277 +               get_device(&evdev->dev);
 278 +       mutex_unlock(&evdev_table_mutex);
 279
 280 -       if (!evdev || !evdev->exist)
 281 +       if (!evdev)
 282                 return -ENODEV;
 283
 284 -       get_device(&evdev->dev);
 285 -
 286         client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
 287         if (!client) {
 288                 error = -ENOMEM;
 289                 goto err_put_evdev;
 290         }
 291
 292 +       spin_lock_init(&client->buffer_lock);
 293         client->evdev = evdev;
 294 -       list_add_tail(&client->node, &evdev->client_list);
 295 +       evdev_attach_client(evdev, client);
 296
 297 -       if (!evdev->open++ && evdev->exist) {
 298 -               error = input_open_device(&evdev->handle);
 299 -               if (error)
 300 -                       goto err_free_client;
 301 -       }
 302 +       error = evdev_open_device(evdev);
 303 +       if (error)
 304 +               goto err_free_client;
 305
 306         file->private_data = client;
 307         return 0;
 308
 309   err_free_client:
 310 -       list_del(&client->node);
 311 +       evdev_detach_client(evdev, client);
 312         kfree(client);
 313   err_put_evdev:
 314         put_device(&evdev->dev);
 315 @@ -197,12 +320,14 @@ static inline size_t evdev_event_size(vo
 316                 sizeof(struct input_event_compat) : sizeof(struct input_event);
 317  }
 318
 319 -static int evdev_event_from_user(const char __user *buffer, struct input_event *event)
 320 +static int evdev_event_from_user(const char __user *buffer,
 321 +                                struct input_event *event)
 322  {
 323         if (COMPAT_TEST) {
 324                 struct input_event_compat compat_event;
 325
 326 -               if (copy_from_user(&compat_event, buffer, sizeof(struct input_event_compat)))
 327 +               if (copy_from_user(&compat_event, buffer,
 328 +                                  sizeof(struct input_event_compat)))
 329                         return -EFAULT;
 330
 331                 event->time.tv_sec = compat_event.time.tv_sec;
 332 @@ -219,7 +344,8 @@ static int evdev_event_from_user(const c
 333         return 0;
 334  }
 335
 336 -static int evdev_event_to_user(char __user *buffer, const struct input_event *event)
 337 +static int evdev_event_to_user(char __user *buffer,
 338 +                               const struct input_event *event)
 339  {
 340         if (COMPAT_TEST) {
 341                 struct input_event_compat compat_event;
 342 @@ -230,7 +356,8 @@ static int evdev_event_to_user(char __us
 343                 compat_event.code = event->code;
 344                 compat_event.value = event->value;
 345
 346 -               if (copy_to_user(buffer, &compat_event, sizeof(struct input_event_compat)))
 347 +               if (copy_to_user(buffer, &compat_event,
 348 +                                sizeof(struct input_event_compat)))
 349                         return -EFAULT;
 350
 351         } else {
 352 @@ -248,7 +375,8 @@ static inline size_t evdev_event_size(vo
 353         return sizeof(struct input_event);
 354  }
 355
 356 -static int evdev_event_from_user(const char __user *buffer, struct input_event *event)
 357 +static int evdev_event_from_user(const char __user *buffer,
 358 +                                struct input_event *event)
 359  {
 360         if (copy_from_user(event, buffer, sizeof(struct input_event)))
 361                 return -EFAULT;
 362 @@ -256,7 +384,8 @@ static int evdev_event_from_user(const c
 363         return 0;
 364  }
 365
 366 -static int evdev_event_to_user(char __user *buffer, const struct input_event *event)
 367 +static int evdev_event_to_user(char __user *buffer,
 368 +                               const struct input_event *event)
 369  {
 370         if (copy_to_user(buffer, event, sizeof(struct input_event)))
 371                 return -EFAULT;
 372 @@ -266,37 +395,71 @@ static int evdev_event_to_user(char __us
 373
 374  #endif /* CONFIG_COMPAT */
 375
 376 -static ssize_t evdev_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 377 +static ssize_t evdev_write(struct file *file, const char __user *buffer,
 378 +                          size_t count, loff_t *ppos)
 379  {
 380         struct evdev_client *client = file->private_data;
 381         struct evdev *evdev = client->evdev;
 382         struct input_event event;
 383 -       int retval = 0;
 384 +       int retval;
 385
 386 -       if (!evdev->exist)
 387 -               return -ENODEV;
 388 +       retval = mutex_lock_interruptible(&evdev->mutex);
 389 +       if (retval)
 390 +               return retval;
 391 +
 392 +       if (!evdev->exist) {
 393 +               retval = -ENODEV;
 394 +               goto out;
 395 +       }
 396
 397         while (retval < count) {
 398
 399 -               if (evdev_event_from_user(buffer + retval, &event))
 400 -                       return -EFAULT;
 401 -               input_inject_event(&evdev->handle, event.type, event.code, event.value);
 402 +               if (evdev_event_from_user(buffer + retval, &event)) {
 403 +                       retval = -EFAULT;
 404 +                       goto out;
 405 +               }
 406 +
 407 +               input_inject_event(&evdev->handle,
 408 +                                  event.type, event.code, event.value);
 409                 retval += evdev_event_size();
 410         }
 411
 412 + out:
 413 +       mutex_unlock(&evdev->mutex);
 414         return retval;
 415  }
 416
 417 -static ssize_t evdev_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 418 +static int evdev_fetch_next_event(struct evdev_client *client,
 419 +                                 struct input_event *event)
 420 +{
 421 +       int have_event;
 422 +
 423 +       spin_lock_irq(&client->buffer_lock);
 424 +
 425 +       have_event = client->head != client->tail;
 426 +       if (have_event) {
 427 +               *event = client->buffer[client->tail++];
 428 +               client->tail &= EVDEV_BUFFER_SIZE - 1;
 429 +       }
 430 +
 431 +       spin_unlock_irq(&client->buffer_lock);
 432 +
 433 +       return have_event;
 434 +}
 435 +
 436 +static ssize_t evdev_read(struct file *file, char __user *buffer,
 437 +                         size_t count, loff_t *ppos)
 438  {
 439         struct evdev_client *client = file->private_data;
 440         struct evdev *evdev = client->evdev;
 441 +       struct input_event event;
 442         int retval;
 443
 444         if (count < evdev_event_size())
 445                 return -EINVAL;
 446
 447 -       if (client->head == client->tail && evdev->exist && (file->f_flags & O_NONBLOCK))
 448 +       if (client->head == client->tail && evdev->exist &&
 449 +           (file->f_flags & O_NONBLOCK))
 450                 return -EAGAIN;
 451
 452         retval = wait_event_interruptible(evdev->wait,
 453 @@ -307,14 +470,12 @@ static ssize_t evdev_read(struct file *f
 454         if (!evdev->exist)
 455                 return -ENODEV;
 456
 457 -       while (client->head != client->tail && retval + evdev_event_size() <= count) {
 458 -
 459 -               struct input_event *event = (struct input_event *) client->buffer + client->tail;
 460 +       while (retval + evdev_event_size() <= count &&
 461 +              evdev_fetch_next_event(client, &event)) {
 462
 463 -               if (evdev_event_to_user(buffer + retval, event))
 464 +               if (evdev_event_to_user(buffer + retval, &event))
 465                         return -EFAULT;
 466
 467 -               client->tail = (client->tail + 1) & (EVDEV_BUFFER_SIZE - 1);
 468                 retval += evdev_event_size();
 469         }
 470
 471 @@ -409,8 +570,8 @@ static int str_to_user(const char *str,
 472         return copy_to_user(p, str, len) ? -EFAULT : len;
 473  }
 474
 475 -static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 476 -                               void __user *p, int compat_mode)
 477 +static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 478 +                          void __user *p, int compat_mode)
 479  {
 480         struct evdev_client *client = file->private_data;
 481         struct evdev *evdev = client->evdev;
 482 @@ -421,186 +582,208 @@ static long evdev_ioctl_handler(struct f
 483         int i, t, u, v;
 484         int error;
 485
 486 -       if (!evdev->exist)
 487 -               return -ENODEV;
 488 -
 489         switch (cmd) {
 490
 491 -               case EVIOCGVERSION:
 492 -                       return put_user(EV_VERSION, ip);
 493 +       case EVIOCGVERSION:
 494 +               return put_user(EV_VERSION, ip);
 495
 496 -               case EVIOCGID:
 497 -                       if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 498 -                               return -EFAULT;
 499 -                       return 0;
 500 +       case EVIOCGID:
 501 +               if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 502 +                       return -EFAULT;
 503 +               return 0;
 504
 505 -               case EVIOCGREP:
 506 -                       if (!test_bit(EV_REP, dev->evbit))
 507 -                               return -ENOSYS;
 508 -                       if (put_user(dev->rep[REP_DELAY], ip))
 509 -                               return -EFAULT;
 510 -                       if (put_user(dev->rep[REP_PERIOD], ip + 1))
 511 -                               return -EFAULT;
 512 -                       return 0;
 513 +       case EVIOCGREP:
 514 +               if (!test_bit(EV_REP, dev->evbit))
 515 +                       return -ENOSYS;
 516 +               if (put_user(dev->rep[REP_DELAY], ip))
 517 +                       return -EFAULT;
 518 +               if (put_user(dev->rep[REP_PERIOD], ip + 1))
 519 +                       return -EFAULT;
 520 +               return 0;
 521
 522 -               case EVIOCSREP:
 523 -                       if (!test_bit(EV_REP, dev->evbit))
 524 -                               return -ENOSYS;
 525 -                       if (get_user(u, ip))
 526 -                               return -EFAULT;
 527 -                       if (get_user(v, ip + 1))
 528 -                               return -EFAULT;
 529 +       case EVIOCSREP:
 530 +               if (!test_bit(EV_REP, dev->evbit))
 531 +                       return -ENOSYS;
 532 +               if (get_user(u, ip))
 533 +                       return -EFAULT;
 534 +               if (get_user(v, ip + 1))
 535 +                       return -EFAULT;
 536
 537 -                       input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 538 -                       input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 539 +               input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 540 +               input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 541
 542 -                       return 0;
 543 +               return 0;
 544
 545 -               case EVIOCGKEYCODE:
 546 -                       if (get_user(t, ip))
 547 -                               return -EFAULT;
 548 +       case EVIOCGKEYCODE:
 549 +               if (get_user(t, ip))
 550 +                       return -EFAULT;
 551
 552 -                       error = dev->getkeycode(dev, t, &v);
 553 -                       if (error)
 554 -                               return error;
 555 +               error = dev->getkeycode(dev, t, &v);
 556 +               if (error)
 557 +                       return error;
 558
 559 -                       if (put_user(v, ip + 1))
 560 -                               return -EFAULT;
 561 +               if (put_user(v, ip + 1))
 562 +                       return -EFAULT;
 563
 564 -                       return 0;
 565 +               return 0;
 566
 567 -               case EVIOCSKEYCODE:
 568 -                       if (get_user(t, ip) || get_user(v, ip + 1))
 569 -                               return -EFAULT;
 570 +       case EVIOCSKEYCODE:
 571 +               if (get_user(t, ip) || get_user(v, ip + 1))
 572 +                       return -EFAULT;
 573
 574 -                       return dev->setkeycode(dev, t, v);
 575 +               return dev->setkeycode(dev, t, v);
 576
 577 -               case EVIOCSFF:
 578 -                       if (copy_from_user(&effect, p, sizeof(effect)))
 579 -                               return -EFAULT;
 580 +       case EVIOCSFF:
 581 +               if (copy_from_user(&effect, p, sizeof(effect)))
 582 +                       return -EFAULT;
 583
 584 -                       error = input_ff_upload(dev, &effect, file);
 585 +               error = input_ff_upload(dev, &effect, file);
 586
 587 -                       if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 588 -                               return -EFAULT;
 589 +               if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 590 +                       return -EFAULT;
 591
 592 -                       return error;
 593 +               return error;
 594
 595 -               case EVIOCRMFF:
 596 -                       return input_ff_erase(dev, (int)(unsigned long) p, file);
 597 +       case EVIOCRMFF:
 598 +               return input_ff_erase(dev, (int)(unsigned long) p, file);
 599
 600 -               case EVIOCGEFFECTS:
 601 -                       i = test_bit(EV_FF, dev->evbit) ? dev->ff->max_effects : 0;
 602 -                       if (put_user(i, ip))
 603 -                               return -EFAULT;
 604 -                       return 0;
 605 +       case EVIOCGEFFECTS:
 606 +               i = test_bit(EV_FF, dev->evbit) ?
 607 +                               dev->ff->max_effects : 0;
 608 +               if (put_user(i, ip))
 609 +                       return -EFAULT;
 610 +               return 0;
 611
 612 -               case EVIOCGRAB:
 613 -                       if (p) {
 614 -                               if (evdev->grab)
 615 -                                       return -EBUSY;
 616 -                               if (input_grab_device(&evdev->handle))
 617 -                                       return -EBUSY;
 618 -                               evdev->grab = client;
 619 -                               return 0;
 620 -                       } else {
 621 -                               if (evdev->grab != client)
 622 -                                       return -EINVAL;
 623 -                               input_release_device(&evdev->handle);
 624 -                               evdev->grab = NULL;
 625 -                               return 0;
 626 +       case EVIOCGRAB:
 627 +               if (p)
 628 +                       return evdev_grab(evdev, client);
 629 +               else
 630 +                       return evdev_ungrab(evdev, client);
 631 +
 632 +       default:
 633 +
 634 +               if (_IOC_TYPE(cmd) != 'E')
 635 +                       return -EINVAL;
 636 +
 637 +               if (_IOC_DIR(cmd) == _IOC_READ) {
 638 +
 639 +                       if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
 640 +
 641 +                               unsigned long *bits;
 642 +                               int len;
 643 +
 644 +                               switch (_IOC_NR(cmd) & EV_MAX) {
 645 +
 646 +                               case      0: bits = dev->evbit;  len = EV_MAX;  break;
 647 +                               case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 648 +                               case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 649 +                               case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 650 +                               case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 651 +                               case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 652 +                               case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 653 +                               case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 654 +                               case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 655 +                               default: return -EINVAL;
 656 +                       }
 657 +                               return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 658                         }
 659
 660 -               default:
 661 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 662 +                               return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 663 +                                                   p, compat_mode);
 664
 665 -                       if (_IOC_TYPE(cmd) != 'E')
 666 -                               return -EINVAL;
 667 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 668 +                               return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 669 +                                                   p, compat_mode);
 670
 671 -                       if (_IOC_DIR(cmd) == _IOC_READ) {
 672 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 673 +                               return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 674 +                                                   p, compat_mode);
 675
 676 -                               if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0,0))) {
 677 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 678 +                               return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 679 +                                                   p, compat_mode);
 680
 681 -                                       unsigned long *bits;
 682 -                                       int len;
 683 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 684 +                               return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 685
 686 -                                       switch (_IOC_NR(cmd) & EV_MAX) {
 687 -                                               case      0: bits = dev->evbit;  len = EV_MAX;  break;
 688 -                                               case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 689 -                                               case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 690 -                                               case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 691 -                                               case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 692 -                                               case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 693 -                                               case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 694 -                                               case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 695 -                                               case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 696 -                                               default: return -EINVAL;
 697 -                                       }
 698 -                                       return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 699 -                               }
 700 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 701 +                               return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 702
 703 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 704 -                                       return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 705 -                                                           p, compat_mode);
 706 +                       if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 707 +                               return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 708
 709 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 710 -                                       return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 711 -                                                           p, compat_mode);
 712 +                       if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 713
 714 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 715 -                                       return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 716 -                                                           p, compat_mode);
 717 +                               t = _IOC_NR(cmd) & ABS_MAX;
 718
 719 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 720 -                                       return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 721 -                                                           p, compat_mode);
 722 +                               abs.value = dev->abs[t];
 723 +                               abs.minimum = dev->absmin[t];
 724 +                               abs.maximum = dev->absmax[t];
 725 +                               abs.fuzz = dev->absfuzz[t];
 726 +                               abs.flat = dev->absflat[t];
 727
 728 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 729 -                                       return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 730 +                               if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
 731 +                                       return -EFAULT;
 732
 733 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 734 -                                       return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 735 +                               return 0;
 736 +                       }
 737
 738 -                               if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 739 -                                       return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 740 +               }
 741
 742 -                               if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 743 +               if (_IOC_DIR(cmd) == _IOC_WRITE) {
 744
 745 -                                       t = _IOC_NR(cmd) & ABS_MAX;
 746 +                       if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 747
 748 -                                       abs.value = dev->abs[t];
 749 -                                       abs.minimum = dev->absmin[t];
 750 -                                       abs.maximum = dev->absmax[t];
 751 -                                       abs.fuzz = dev->absfuzz[t];
 752 -                                       abs.flat = dev->absflat[t];
 753 +                               t = _IOC_NR(cmd) & ABS_MAX;
 754
 755 -                                       if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
 756 -                                               return -EFAULT;
 757 +                               if (copy_from_user(&abs, p,
 758 +                                               sizeof(struct input_absinfo)))
 759 +                                       return -EFAULT;
 760 +
 761 +                               /*
 762 +                                * Take event lock to ensure that we are not
 763 +                                * changing device parameters in the middle
 764 +                                * of event.
 765 +                                */
 766 +                               spin_lock_irq(&dev->event_lock);
 767 +
 768 +                               dev->abs[t] = abs.value;
 769 +                               dev->absmin[t] = abs.minimum;
 770 +                               dev->absmax[t] = abs.maximum;
 771 +                               dev->absfuzz[t] = abs.fuzz;
 772 +                               dev->absflat[t] = abs.flat;
 773
 774 -                                       return 0;
 775 -                               }
 776 +                               spin_unlock_irq(&dev->event_lock);
 777
 778 +                               return 0;
 779                         }
 780 +               }
 781 +       }
 782 +       return -EINVAL;
 783 +}
 784
 785 -                       if (_IOC_DIR(cmd) == _IOC_WRITE) {
 786 -
 787 -                               if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 788 +static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 789 +                               void __user *p, int compat_mode)
 790 +{
 791 +       struct evdev_client *client = file->private_data;
 792 +       struct evdev *evdev = client->evdev;
 793 +       int retval;
 794
 795 -                                       t = _IOC_NR(cmd) & ABS_MAX;
 796 +       retval = mutex_lock_interruptible(&evdev->mutex);
 797 +       if (retval)
 798 +               return retval;
 799
 800 -                                       if (copy_from_user(&abs, p, sizeof(struct input_absinfo)))
 801 -                                               return -EFAULT;
 802 +       if (!evdev->exist) {
 803 +               retval = -ENODEV;
 804 +               goto out;
 805 +       }
 806
 807 -                                       dev->abs[t] = abs.value;
 808 -                                       dev->absmin[t] = abs.minimum;
 809 -                                       dev->absmax[t] = abs.maximum;
 810 -                                       dev->absfuzz[t] = abs.fuzz;
 811 -                                       dev->absflat[t] = abs.flat;
 812 +       retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 813
 814 -                                       return 0;
 815 -                               }
 816 -                       }
 817 -       }
 818 -       return -EINVAL;
 819 + out:
 820 +       mutex_unlock(&evdev->mutex);
 821 +       return retval;
 822  }
 823
 824  static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 825 @@ -609,27 +792,79 @@ static long evdev_ioctl(struct file *fil
 826  }
 827
 828  #ifdef CONFIG_COMPAT
 829 -static long evdev_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
 830 +static long evdev_ioctl_compat(struct file *file,
 831 +                               unsigned int cmd, unsigned long arg)
 832  {
 833         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 834  }
 835  #endif
 836
 837  static const struct file_operations evdev_fops = {
 838 -       .owner =        THIS_MODULE,
 839 -       .read =         evdev_read,
 840 -       .write =        evdev_write,
 841 -       .poll =         evdev_poll,
 842 -       .open =         evdev_open,
 843 -       .release =      evdev_release,
 844 -       .unlocked_ioctl = evdev_ioctl,
 845 +       .owner          = THIS_MODULE,
 846 +       .read           = evdev_read,
 847 +       .write          = evdev_write,
 848 +       .poll           = evdev_poll,
 849 +       .open           = evdev_open,
 850 +       .release        = evdev_release,
 851 +       .unlocked_ioctl = evdev_ioctl,
 852  #ifdef CONFIG_COMPAT
 853 -       .compat_ioctl = evdev_ioctl_compat,
 854 +       .compat_ioctl   = evdev_ioctl_compat,
 855  #endif
 856 -       .fasync =       evdev_fasync,
 857 -       .flush =        evdev_flush
 858 +       .fasync         = evdev_fasync,
 859 +       .flush          = evdev_flush
 860  };
 861
 862 +static int evdev_install_chrdev(struct evdev *evdev)
 863 +{
 864 +       /*
 865 +        * No need to do any locking here as calls to connect and
 866 +        * disconnect are serialized by the input core
 867 +        */
 868 +       evdev_table[evdev->minor] = evdev;
 869 +       return 0;
 870 +}
 871 +
 872 +static void evdev_remove_chrdev(struct evdev *evdev)
 873 +{
 874 +       /*
 875 +        * Lock evdev table to prevent race with evdev_open()
 876 +        */
 877 +       mutex_lock(&evdev_table_mutex);
 878 +       evdev_table[evdev->minor] = NULL;
 879 +       mutex_unlock(&evdev_table_mutex);
 880 +}
 881 +
 882 +/*
 883 + * Mark device non-existent. This disables writes, ioctls and
 884 + * prevents new users from opening the device. Already posted
 885 + * blocking reads will stay, however new ones will fail.
 886 + */
 887 +static void evdev_mark_dead(struct evdev *evdev)
 888 +{
 889 +       mutex_lock(&evdev->mutex);
 890 +       evdev->exist = 0;
 891 +       mutex_unlock(&evdev->mutex);
 892 +}
 893 +
 894 +static void evdev_cleanup(struct evdev *evdev)
 895 +{
 896 +       struct input_handle *handle = &evdev->handle;
 897 +
 898 +       evdev_mark_dead(evdev);
 899 +       evdev_hangup(evdev);
 900 +       evdev_remove_chrdev(evdev);
 901 +
 902 +       /* evdev is marked dead so no one else accesses evdev->open */
 903 +       if (evdev->open) {
 904 +               input_flush_device(handle, NULL);
 905 +               input_close_device(handle);
 906 +       }
 907 +}
 908 +
 909 +/*
 910 + * Create new evdev device. Note that input core serializes calls
 911 + * to connect and disconnect so we don't need to lock evdev_table here.
 912 + */
 913  static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 914                          const struct input_device_id *id)
 915  {
 916 @@ -637,7 +872,10 @@ static int evdev_connect(struct input_ha
 917         int minor;
 918         int error;
 919
 920 -       for (minor = 0; minor < EVDEV_MINORS && evdev_table[minor]; minor++);
 921 +       for (minor = 0; minor < EVDEV_MINORS; minor++)
 922 +               if (!evdev_table[minor])
 923 +                       break;
 924 +
 925         if (minor == EVDEV_MINORS) {
 926                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 927                 return -ENFILE;
 928 @@ -648,38 +886,44 @@ static int evdev_connect(struct input_ha
 929                 return -ENOMEM;
 930
 931         INIT_LIST_HEAD(&evdev->client_list);
 932 +       spin_lock_init(&evdev->client_lock);
 933 +       mutex_init(&evdev->mutex);
 934         init_waitqueue_head(&evdev->wait);
 935
 936 +       snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
 937         evdev->exist = 1;
 938         evdev->minor = minor;
 939 +
 940         evdev->handle.dev = dev;
 941         evdev->handle.name = evdev->name;
 942         evdev->handle.handler = handler;
 943         evdev->handle.private = evdev;
 944 -       snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
 945
 946 -       snprintf(evdev->dev.bus_id, sizeof(evdev->dev.bus_id),
 947 -                "event%d", minor);
 948 +       strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
 949 +       evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 950         evdev->dev.class = &input_class;
 951         evdev->dev.parent = &dev->dev;
 952 -       evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 953         evdev->dev.release = evdev_free;
 954         device_initialize(&evdev->dev);
 955
 956 -       evdev_table[minor] = evdev;
 957 -
 958 -       error = device_add(&evdev->dev);
 959 +       error = input_register_handle(&evdev->handle);
 960         if (error)
 961                 goto err_free_evdev;
 962
 963 -       error = input_register_handle(&evdev->handle);
 964 +       error = evdev_install_chrdev(evdev);
 965 +       if (error)
 966 +               goto err_unregister_handle;
 967 +
 968 +       error = device_add(&evdev->dev);
 969         if (error)
 970 -               goto err_delete_evdev;
 971 +               goto err_cleanup_evdev;
 972
 973         return 0;
 974
 975 - err_delete_evdev:
 976 -       device_del(&evdev->dev);
 977 + err_cleanup_evdev:
 978 +       evdev_cleanup(evdev);
 979 + err_unregister_handle:
 980 +       input_unregister_handle(&evdev->handle);
 981   err_free_evdev:
 982         put_device(&evdev->dev);
 983         return error;
 984 @@ -688,21 +932,10 @@ static int evdev_connect(struct input_ha
 985  static void evdev_disconnect(struct input_handle *handle)
 986  {
 987         struct evdev *evdev = handle->private;
 988 -       struct evdev_client *client;
 989
 990 -       input_unregister_handle(handle);
 991         device_del(&evdev->dev);
 992 -
 993 -       evdev->exist = 0;
 994 -
 995 -       if (evdev->open) {
 996 -               input_flush_device(handle, NULL);
 997 -               input_close_device(handle);
 998 -               list_for_each_entry(client, &evdev->client_list, node)
 999 -                       kill_fasync(&client->fasync, SIGIO, POLL_HUP);
1000 -               wake_up_interruptible(&evdev->wait);
1001 -       }
1002 -
1003 +       evdev_cleanup(evdev);
1004 +       input_unregister_handle(handle);
1005         put_device(&evdev->dev);
1006  }
1007
1008 @@ -714,13 +947,13 @@ static const struct input_device_id evde
1009  MODULE_DEVICE_TABLE(input, evdev_ids);
1010
1011  static struct input_handler evdev_handler = {
1012 -       .event =        evdev_event,
1013 -       .connect =      evdev_connect,
1014 -       .disconnect =   evdev_disconnect,
1015 -       .fops =         &evdev_fops,
1016 -       .minor =        EVDEV_MINOR_BASE,
1017 -       .name =         "evdev",
1018 -       .id_table =     evdev_ids,
1019 +       .event          = evdev_event,
1020 +       .connect        = evdev_connect,
1021 +       .disconnect     = evdev_disconnect,
1022 +       .fops           = &evdev_fops,
1023 +       .minor          = EVDEV_MINOR_BASE,
1024 +       .name           = "evdev",
1025 +       .id_table       = evdev_ids,
1026  };
1027
1028  static int __init evdev_init(void)