sound/core/control.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Routines for driver control interface
   4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   5  */
   6
   7 #include <linux/threads.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/slab.h>
  12 #include <linux/vmalloc.h>
  13 #include <linux/time.h>
  14 #include <linux/mm.h>
  15 #include <linux/math64.h>
  16 #include <linux/sched/signal.h>
  17 #include <sound/core.h>
  18 #include <sound/minors.h>
  19 #include <sound/info.h>
  20 #include <sound/control.h>
  21
  22 // Max allocation size for user controls.
  23 static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
  24 module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
  25 MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
  26
  27 #define MAX_CONTROL_COUNT       1028
  28
  29 struct snd_kctl_ioctl {
  30         struct list_head list;          /* list of all ioctls */
  31         snd_kctl_ioctl_func_t fioctl;
  32 };
  33
  34 static DECLARE_RWSEM(snd_ioctl_rwsem);
  35 static DECLARE_RWSEM(snd_ctl_layer_rwsem);
  36 static LIST_HEAD(snd_control_ioctls);
  37 #ifdef CONFIG_COMPAT
  38 static LIST_HEAD(snd_control_compat_ioctls);
  39 #endif
  40 static struct snd_ctl_layer_ops *snd_ctl_layer;
  41
  42 static int snd_ctl_open(struct inode *inode, struct file *file)
  43 {
  44         unsigned long flags;
  45         struct snd_card *card;
  46         struct snd_ctl_file *ctl;
  47         int i, err;
  48
  49         err = stream_open(inode, file);
  50         if (err < 0)
  51                 return err;
  52
  53         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  54         if (!card) {
  55                 err = -ENODEV;
  56                 goto __error1;
  57         }
  58         err = snd_card_file_add(card, file);
  59         if (err < 0) {
  60                 err = -ENODEV;
  61                 goto __error1;
  62         }
  63         if (!try_module_get(card->module)) {
  64                 err = -EFAULT;
  65                 goto __error2;
  66         }
  67         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  68         if (ctl == NULL) {
  69                 err = -ENOMEM;
  70                 goto __error;
  71         }
  72         INIT_LIST_HEAD(&ctl->events);
  73         init_waitqueue_head(&ctl->change_sleep);
  74         spin_lock_init(&ctl->read_lock);
  75         ctl->card = card;
  76         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  77                 ctl->preferred_subdevice[i] = -1;
  78         ctl->pid = get_pid(task_pid(current));
  79         file->private_data = ctl;
  80         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  81         list_add_tail(&ctl->list, &card->ctl_files);
  82         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  83         snd_card_unref(card);
  84         return 0;
  85
  86       __error:
  87         module_put(card->module);
  88       __error2:
  89         snd_card_file_remove(card, file);
  90       __error1:
  91         if (card)
  92                 snd_card_unref(card);
  93         return err;
  94 }
  95
  96 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  97 {
  98         unsigned long flags;
  99         struct snd_kctl_event *cread;
 100
 101         spin_lock_irqsave(&ctl->read_lock, flags);
 102         while (!list_empty(&ctl->events)) {
 103                 cread = snd_kctl_event(ctl->events.next);
 104                 list_del(&cread->list);
 105                 kfree(cread);
 106         }
 107         spin_unlock_irqrestore(&ctl->read_lock, flags);
 108 }
 109
 110 static int snd_ctl_release(struct inode *inode, struct file *file)
 111 {
 112         unsigned long flags;
 113         struct snd_card *card;
 114         struct snd_ctl_file *ctl;
 115         struct snd_kcontrol *control;
 116         unsigned int idx;
 117
 118         ctl = file->private_data;
 119         file->private_data = NULL;
 120         card = ctl->card;
 121         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 122         list_del(&ctl->list);
 123         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 124         down_write(&card->controls_rwsem);
 125         list_for_each_entry(control, &card->controls, list)
 126                 for (idx = 0; idx < control->count; idx++)
 127                         if (control->vd[idx].owner == ctl)
 128                                 control->vd[idx].owner = NULL;
 129         up_write(&card->controls_rwsem);
 130         snd_ctl_empty_read_queue(ctl);
 131         put_pid(ctl->pid);
 132         kfree(ctl);
 133         module_put(card->module);
 134         snd_card_file_remove(card, file);
 135         return 0;
 136 }
 137
 138 /**
 139  * snd_ctl_notify - Send notification to user-space for a control change
 140  * @card: the card to send notification
 141  * @mask: the event mask, SNDRV_CTL_EVENT_*
 142  * @id: the ctl element id to send notification
 143  *
 144  * This function adds an event record with the given id and mask, appends
 145  * to the list and wakes up the user-space for notification.  This can be
 146  * called in the atomic context.
 147  */
 148 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 149                     struct snd_ctl_elem_id *id)
 150 {
 151         unsigned long flags;
 152         struct snd_ctl_file *ctl;
 153         struct snd_kctl_event *ev;
 154
 155         if (snd_BUG_ON(!card || !id))
 156                 return;
 157         if (card->shutdown)
 158                 return;
 159         read_lock_irqsave(&card->ctl_files_rwlock, flags);
 160 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 161         card->mixer_oss_change_count++;
 162 #endif
 163         list_for_each_entry(ctl, &card->ctl_files, list) {
 164                 if (!ctl->subscribed)
 165                         continue;
 166                 spin_lock(&ctl->read_lock);
 167                 list_for_each_entry(ev, &ctl->events, list) {
 168                         if (ev->id.numid == id->numid) {
 169                                 ev->mask |= mask;
 170                                 goto _found;
 171                         }
 172                 }
 173                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 174                 if (ev) {
 175                         ev->id = *id;
 176                         ev->mask = mask;
 177                         list_add_tail(&ev->list, &ctl->events);
 178                 } else {
 179                         dev_err(card->dev, "No memory available to allocate event\n");
 180                 }
 181         _found:
 182                 wake_up(&ctl->change_sleep);
 183                 spin_unlock(&ctl->read_lock);
 184                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 185         }
 186         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 187 }
 188 EXPORT_SYMBOL(snd_ctl_notify);
 189
 190 /**
 191  * snd_ctl_notify_one - Send notification to user-space for a control change
 192  * @card: the card to send notification
 193  * @mask: the event mask, SNDRV_CTL_EVENT_*
 194  * @kctl: the pointer with the control instance
 195  * @ioff: the additional offset to the control index
 196  *
 197  * This function calls snd_ctl_notify() and does additional jobs
 198  * like LED state changes.
 199  */
 200 void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
 201                         struct snd_kcontrol *kctl, unsigned int ioff)
 202 {
 203         struct snd_ctl_elem_id id = kctl->id;
 204         struct snd_ctl_layer_ops *lops;
 205
 206         id.index += ioff;
 207         id.numid += ioff;
 208         snd_ctl_notify(card, mask, &id);
 209         down_read(&snd_ctl_layer_rwsem);
 210         for (lops = snd_ctl_layer; lops; lops = lops->next)
 211                 lops->lnotify(card, mask, kctl, ioff);
 212         up_read(&snd_ctl_layer_rwsem);
 213 }
 214 EXPORT_SYMBOL(snd_ctl_notify_one);
 215
 216 /**
 217  * snd_ctl_new - create a new control instance with some elements
 218  * @kctl: the pointer to store new control instance
 219  * @count: the number of elements in this control
 220  * @access: the default access flags for elements in this control
 221  * @file: given when locking these elements
 222  *
 223  * Allocates a memory object for a new control instance. The instance has
 224  * elements as many as the given number (@count). Each element has given
 225  * access permissions (@access). Each element is locked when @file is given.
 226  *
 227  * Return: 0 on success, error code on failure
 228  */
 229 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 230                        unsigned int access, struct snd_ctl_file *file)
 231 {
 232         unsigned int idx;
 233
 234         if (count == 0 || count > MAX_CONTROL_COUNT)
 235                 return -EINVAL;
 236
 237         *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
 238         if (!*kctl)
 239                 return -ENOMEM;
 240
 241         for (idx = 0; idx < count; idx++) {
 242                 (*kctl)->vd[idx].access = access;
 243                 (*kctl)->vd[idx].owner = file;
 244         }
 245         (*kctl)->count = count;
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * snd_ctl_new1 - create a control instance from the template
 252  * @ncontrol: the initialization record
 253  * @private_data: the private data to set
 254  *
 255  * Allocates a new struct snd_kcontrol instance and initialize from the given
 256  * template.  When the access field of ncontrol is 0, it's assumed as
 257  * READWRITE access. When the count field is 0, it's assumes as one.
 258  *
 259  * Return: The pointer of the newly generated instance, or %NULL on failure.
 260  */
 261 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 262                                   void *private_data)
 263 {
 264         struct snd_kcontrol *kctl;
 265         unsigned int count;
 266         unsigned int access;
 267         int err;
 268
 269         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 270                 return NULL;
 271
 272         count = ncontrol->count;
 273         if (count == 0)
 274                 count = 1;
 275
 276         access = ncontrol->access;
 277         if (access == 0)
 278                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 279         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 280                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 281                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 282                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 283                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 284                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
 285                    SNDRV_CTL_ELEM_ACCESS_LED_MASK |
 286                    SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
 287
 288         err = snd_ctl_new(&kctl, count, access, NULL);
 289         if (err < 0)
 290                 return NULL;
 291
 292         /* The 'numid' member is decided when calling snd_ctl_add(). */
 293         kctl->id.iface = ncontrol->iface;
 294         kctl->id.device = ncontrol->device;
 295         kctl->id.subdevice = ncontrol->subdevice;
 296         if (ncontrol->name) {
 297                 strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 298                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 299                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 300                                 ncontrol->name, kctl->id.name);
 301         }
 302         kctl->id.index = ncontrol->index;
 303
 304         kctl->info = ncontrol->info;
 305         kctl->get = ncontrol->get;
 306         kctl->put = ncontrol->put;
 307         kctl->tlv.p = ncontrol->tlv.p;
 308
 309         kctl->private_value = ncontrol->private_value;
 310         kctl->private_data = private_data;
 311
 312         return kctl;
 313 }
 314 EXPORT_SYMBOL(snd_ctl_new1);
 315
 316 /**
 317  * snd_ctl_free_one - release the control instance
 318  * @kcontrol: the control instance
 319  *
 320  * Releases the control instance created via snd_ctl_new()
 321  * or snd_ctl_new1().
 322  * Don't call this after the control was added to the card.
 323  */
 324 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 325 {
 326         if (kcontrol) {
 327                 if (kcontrol->private_free)
 328                         kcontrol->private_free(kcontrol);
 329                 kfree(kcontrol);
 330         }
 331 }
 332 EXPORT_SYMBOL(snd_ctl_free_one);
 333
 334 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 335                                           unsigned int count)
 336 {
 337         struct snd_kcontrol *kctl;
 338
 339         /* Make sure that the ids assigned to the control do not wrap around */
 340         if (card->last_numid >= UINT_MAX - count)
 341                 card->last_numid = 0;
 342
 343         list_for_each_entry(kctl, &card->controls, list) {
 344                 if (kctl->id.numid < card->last_numid + 1 + count &&
 345                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 346                         card->last_numid = kctl->id.numid + kctl->count - 1;
 347                         return true;
 348                 }
 349         }
 350         return false;
 351 }
 352
 353 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 354 {
 355         unsigned int iter = 100000;
 356
 357         while (snd_ctl_remove_numid_conflict(card, count)) {
 358                 if (--iter == 0) {
 359                         /* this situation is very unlikely */
 360                         dev_err(card->dev, "unable to allocate new control numid\n");
 361                         return -ENOMEM;
 362                 }
 363         }
 364         return 0;
 365 }
 366
 367 enum snd_ctl_add_mode {
 368         CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
 369 };
 370
 371 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
 372 static int __snd_ctl_add_replace(struct snd_card *card,
 373                                  struct snd_kcontrol *kcontrol,
 374                                  enum snd_ctl_add_mode mode)
 375 {
 376         struct snd_ctl_elem_id id;
 377         unsigned int idx;
 378         struct snd_kcontrol *old;
 379         int err;
 380
 381         id = kcontrol->id;
 382         if (id.index > UINT_MAX - kcontrol->count)
 383                 return -EINVAL;
 384
 385         old = snd_ctl_find_id(card, &id);
 386         if (!old) {
 387                 if (mode == CTL_REPLACE)
 388                         return -EINVAL;
 389         } else {
 390                 if (mode == CTL_ADD_EXCLUSIVE) {
 391                         dev_err(card->dev,
 392                                 "control %i:%i:%i:%s:%i is already present\n",
 393                                 id.iface, id.device, id.subdevice, id.name,
 394                                 id.index);
 395                         return -EBUSY;
 396                 }
 397
 398                 err = snd_ctl_remove(card, old);
 399                 if (err < 0)
 400                         return err;
 401         }
 402
 403         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 404                 return -ENOMEM;
 405
 406         list_add_tail(&kcontrol->list, &card->controls);
 407         card->controls_count += kcontrol->count;
 408         kcontrol->id.numid = card->last_numid + 1;
 409         card->last_numid += kcontrol->count;
 410
 411         for (idx = 0; idx < kcontrol->count; idx++)
 412                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
 413
 414         return 0;
 415 }
 416
 417 static int snd_ctl_add_replace(struct snd_card *card,
 418                                struct snd_kcontrol *kcontrol,
 419                                enum snd_ctl_add_mode mode)
 420 {
 421         int err = -EINVAL;
 422
 423         if (! kcontrol)
 424                 return err;
 425         if (snd_BUG_ON(!card || !kcontrol->info))
 426                 goto error;
 427
 428         down_write(&card->controls_rwsem);
 429         err = __snd_ctl_add_replace(card, kcontrol, mode);
 430         up_write(&card->controls_rwsem);
 431         if (err < 0)
 432                 goto error;
 433         return 0;
 434
 435  error:
 436         snd_ctl_free_one(kcontrol);
 437         return err;
 438 }
 439
 440 /**
 441  * snd_ctl_add - add the control instance to the card
 442  * @card: the card instance
 443  * @kcontrol: the control instance to add
 444  *
 445  * Adds the control instance created via snd_ctl_new() or
 446  * snd_ctl_new1() to the given card. Assigns also an unique
 447  * numid used for fast search.
 448  *
 449  * It frees automatically the control which cannot be added.
 450  *
 451  * Return: Zero if successful, or a negative error code on failure.
 452  *
 453  */
 454 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 455 {
 456         return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
 457 }
 458 EXPORT_SYMBOL(snd_ctl_add);
 459
 460 /**
 461  * snd_ctl_replace - replace the control instance of the card
 462  * @card: the card instance
 463  * @kcontrol: the control instance to replace
 464  * @add_on_replace: add the control if not already added
 465  *
 466  * Replaces the given control.  If the given control does not exist
 467  * and the add_on_replace flag is set, the control is added.  If the
 468  * control exists, it is destroyed first.
 469  *
 470  * It frees automatically the control which cannot be added or replaced.
 471  *
 472  * Return: Zero if successful, or a negative error code on failure.
 473  */
 474 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 475                     bool add_on_replace)
 476 {
 477         return snd_ctl_add_replace(card, kcontrol,
 478                                    add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
 479 }
 480 EXPORT_SYMBOL(snd_ctl_replace);
 481
 482 /**
 483  * snd_ctl_remove - remove the control from the card and release it
 484  * @card: the card instance
 485  * @kcontrol: the control instance to remove
 486  *
 487  * Removes the control from the card and then releases the instance.
 488  * You don't need to call snd_ctl_free_one(). You must be in
 489  * the write lock - down_write(&card->controls_rwsem).
 490  *
 491  * Return: 0 if successful, or a negative error code on failure.
 492  */
 493 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 494 {
 495         unsigned int idx;
 496
 497         if (snd_BUG_ON(!card || !kcontrol))
 498                 return -EINVAL;
 499         list_del(&kcontrol->list);
 500         card->controls_count -= kcontrol->count;
 501         for (idx = 0; idx < kcontrol->count; idx++)
 502                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
 503         snd_ctl_free_one(kcontrol);
 504         return 0;
 505 }
 506 EXPORT_SYMBOL(snd_ctl_remove);
 507
 508 /**
 509  * snd_ctl_remove_id - remove the control of the given id and release it
 510  * @card: the card instance
 511  * @id: the control id to remove
 512  *
 513  * Finds the control instance with the given id, removes it from the
 514  * card list and releases it.
 515  *
 516  * Return: 0 if successful, or a negative error code on failure.
 517  */
 518 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 519 {
 520         struct snd_kcontrol *kctl;
 521         int ret;
 522
 523         down_write(&card->controls_rwsem);
 524         kctl = snd_ctl_find_id(card, id);
 525         if (kctl == NULL) {
 526                 up_write(&card->controls_rwsem);
 527                 return -ENOENT;
 528         }
 529         ret = snd_ctl_remove(card, kctl);
 530         up_write(&card->controls_rwsem);
 531         return ret;
 532 }
 533 EXPORT_SYMBOL(snd_ctl_remove_id);
 534
 535 /**
 536  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 537  * @file: active control handle
 538  * @id: the control id to remove
 539  *
 540  * Finds the control instance with the given id, removes it from the
 541  * card list and releases it.
 542  *
 543  * Return: 0 if successful, or a negative error code on failure.
 544  */
 545 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 546                                    struct snd_ctl_elem_id *id)
 547 {
 548         struct snd_card *card = file->card;
 549         struct snd_kcontrol *kctl;
 550         int idx, ret;
 551
 552         down_write(&card->controls_rwsem);
 553         kctl = snd_ctl_find_id(card, id);
 554         if (kctl == NULL) {
 555                 ret = -ENOENT;
 556                 goto error;
 557         }
 558         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 559                 ret = -EINVAL;
 560                 goto error;
 561         }
 562         for (idx = 0; idx < kctl->count; idx++)
 563                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 564                         ret = -EBUSY;
 565                         goto error;
 566                 }
 567         ret = snd_ctl_remove(card, kctl);
 568 error:
 569         up_write(&card->controls_rwsem);
 570         return ret;
 571 }
 572
 573 /**
 574  * snd_ctl_activate_id - activate/inactivate the control of the given id
 575  * @card: the card instance
 576  * @id: the control id to activate/inactivate
 577  * @active: non-zero to activate
 578  *
 579  * Finds the control instance with the given id, and activate or
 580  * inactivate the control together with notification, if changed.
 581  * The given ID data is filled with full information.
 582  *
 583  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 584  */
 585 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 586                         int active)
 587 {
 588         struct snd_kcontrol *kctl;
 589         struct snd_kcontrol_volatile *vd;
 590         unsigned int index_offset;
 591         int ret;
 592
 593         down_write(&card->controls_rwsem);
 594         kctl = snd_ctl_find_id(card, id);
 595         if (kctl == NULL) {
 596                 ret = -ENOENT;
 597                 goto unlock;
 598         }
 599         index_offset = snd_ctl_get_ioff(kctl, id);
 600         vd = &kctl->vd[index_offset];
 601         ret = 0;
 602         if (active) {
 603                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 604                         goto unlock;
 605                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 606         } else {
 607                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 608                         goto unlock;
 609                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 610         }
 611         snd_ctl_build_ioff(id, kctl, index_offset);
 612         downgrade_write(&card->controls_rwsem);
 613         snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
 614         up_read(&card->controls_rwsem);
 615         return 1;
 616
 617  unlock:
 618         up_write(&card->controls_rwsem);
 619         return ret;
 620 }
 621 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 622
 623 /**
 624  * snd_ctl_rename_id - replace the id of a control on the card
 625  * @card: the card instance
 626  * @src_id: the old id
 627  * @dst_id: the new id
 628  *
 629  * Finds the control with the old id from the card, and replaces the
 630  * id with the new one.
 631  *
 632  * Return: Zero if successful, or a negative error code on failure.
 633  */
 634 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 635                       struct snd_ctl_elem_id *dst_id)
 636 {
 637         struct snd_kcontrol *kctl;
 638
 639         down_write(&card->controls_rwsem);
 640         kctl = snd_ctl_find_id(card, src_id);
 641         if (kctl == NULL) {
 642                 up_write(&card->controls_rwsem);
 643                 return -ENOENT;
 644         }
 645         kctl->id = *dst_id;
 646         kctl->id.numid = card->last_numid + 1;
 647         card->last_numid += kctl->count;
 648         up_write(&card->controls_rwsem);
 649         return 0;
 650 }
 651 EXPORT_SYMBOL(snd_ctl_rename_id);
 652
 653 /**
 654  * snd_ctl_find_numid - find the control instance with the given number-id
 655  * @card: the card instance
 656  * @numid: the number-id to search
 657  *
 658  * Finds the control instance with the given number-id from the card.
 659  *
 660  * The caller must down card->controls_rwsem before calling this function
 661  * (if the race condition can happen).
 662  *
 663  * Return: The pointer of the instance if found, or %NULL if not.
 664  *
 665  */
 666 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 667 {
 668         struct snd_kcontrol *kctl;
 669
 670         if (snd_BUG_ON(!card || !numid))
 671                 return NULL;
 672         list_for_each_entry(kctl, &card->controls, list) {
 673                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 674                         return kctl;
 675         }
 676         return NULL;
 677 }
 678 EXPORT_SYMBOL(snd_ctl_find_numid);
 679
 680 /**
 681  * snd_ctl_find_id - find the control instance with the given id
 682  * @card: the card instance
 683  * @id: the id to search
 684  *
 685  * Finds the control instance with the given id from the card.
 686  *
 687  * The caller must down card->controls_rwsem before calling this function
 688  * (if the race condition can happen).
 689  *
 690  * Return: The pointer of the instance if found, or %NULL if not.
 691  *
 692  */
 693 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 694                                      struct snd_ctl_elem_id *id)
 695 {
 696         struct snd_kcontrol *kctl;
 697
 698         if (snd_BUG_ON(!card || !id))
 699                 return NULL;
 700         if (id->numid != 0)
 701                 return snd_ctl_find_numid(card, id->numid);
 702         list_for_each_entry(kctl, &card->controls, list) {
 703                 if (kctl->id.iface != id->iface)
 704                         continue;
 705                 if (kctl->id.device != id->device)
 706                         continue;
 707                 if (kctl->id.subdevice != id->subdevice)
 708                         continue;
 709                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 710                         continue;
 711                 if (kctl->id.index > id->index)
 712                         continue;
 713                 if (kctl->id.index + kctl->count <= id->index)
 714                         continue;
 715                 return kctl;
 716         }
 717         return NULL;
 718 }
 719 EXPORT_SYMBOL(snd_ctl_find_id);
 720
 721 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 722                              unsigned int cmd, void __user *arg)
 723 {
 724         struct snd_ctl_card_info *info;
 725
 726         info = kzalloc(sizeof(*info), GFP_KERNEL);
 727         if (! info)
 728                 return -ENOMEM;
 729         down_read(&snd_ioctl_rwsem);
 730         info->card = card->number;
 731         strscpy(info->id, card->id, sizeof(info->id));
 732         strscpy(info->driver, card->driver, sizeof(info->driver));
 733         strscpy(info->name, card->shortname, sizeof(info->name));
 734         strscpy(info->longname, card->longname, sizeof(info->longname));
 735         strscpy(info->mixername, card->mixername, sizeof(info->mixername));
 736         strscpy(info->components, card->components, sizeof(info->components));
 737         up_read(&snd_ioctl_rwsem);
 738         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 739                 kfree(info);
 740                 return -EFAULT;
 741         }
 742         kfree(info);
 743         return 0;
 744 }
 745
 746 static int snd_ctl_elem_list(struct snd_card *card,
 747                              struct snd_ctl_elem_list *list)
 748 {
 749         struct snd_kcontrol *kctl;
 750         struct snd_ctl_elem_id id;
 751         unsigned int offset, space, jidx;
 752         int err = 0;
 753
 754         offset = list->offset;
 755         space = list->space;
 756
 757         down_read(&card->controls_rwsem);
 758         list->count = card->controls_count;
 759         list->used = 0;
 760         if (space > 0) {
 761                 list_for_each_entry(kctl, &card->controls, list) {
 762                         if (offset >= kctl->count) {
 763                                 offset -= kctl->count;
 764                                 continue;
 765                         }
 766                         for (jidx = offset; jidx < kctl->count; jidx++) {
 767                                 snd_ctl_build_ioff(&id, kctl, jidx);
 768                                 if (copy_to_user(list->pids + list->used, &id,
 769                                                  sizeof(id))) {
 770                                         err = -EFAULT;
 771                                         goto out;
 772                                 }
 773                                 list->used++;
 774                                 if (!--space)
 775                                         goto out;
 776                         }
 777                         offset = 0;
 778                 }
 779         }
 780  out:
 781         up_read(&card->controls_rwsem);
 782         return err;
 783 }
 784
 785 static int snd_ctl_elem_list_user(struct snd_card *card,
 786                                   struct snd_ctl_elem_list __user *_list)
 787 {
 788         struct snd_ctl_elem_list list;
 789         int err;
 790
 791         if (copy_from_user(&list, _list, sizeof(list)))
 792                 return -EFAULT;
 793         err = snd_ctl_elem_list(card, &list);
 794         if (err)
 795                 return err;
 796         if (copy_to_user(_list, &list, sizeof(list)))
 797                 return -EFAULT;
 798
 799         return 0;
 800 }
 801
 802 /* Check whether the given kctl info is valid */
 803 static int snd_ctl_check_elem_info(struct snd_card *card,
 804                                    const struct snd_ctl_elem_info *info)
 805 {
 806         static const unsigned int max_value_counts[] = {
 807                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
 808                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
 809                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
 810                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
 811                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
 812                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
 813         };
 814
 815         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
 816             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
 817                 if (card)
 818                         dev_err(card->dev,
 819                                 "control %i:%i:%i:%s:%i: invalid type %d\n",
 820                                 info->id.iface, info->id.device,
 821                                 info->id.subdevice, info->id.name,
 822                                 info->id.index, info->type);
 823                 return -EINVAL;
 824         }
 825         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
 826             info->value.enumerated.items == 0) {
 827                 if (card)
 828                         dev_err(card->dev,
 829                                 "control %i:%i:%i:%s:%i: zero enum items\n",
 830                                 info->id.iface, info->id.device,
 831                                 info->id.subdevice, info->id.name,
 832                                 info->id.index);
 833                 return -EINVAL;
 834         }
 835         if (info->count > max_value_counts[info->type]) {
 836                 if (card)
 837                         dev_err(card->dev,
 838                                 "control %i:%i:%i:%s:%i: invalid count %d\n",
 839                                 info->id.iface, info->id.device,
 840                                 info->id.subdevice, info->id.name,
 841                                 info->id.index, info->count);
 842                 return -EINVAL;
 843         }
 844
 845         return 0;
 846 }
 847
 848 /* The capacity of struct snd_ctl_elem_value.value.*/
 849 static const unsigned int value_sizes[] = {
 850         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
 851         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
 852         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
 853         [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
 854         [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
 855         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
 856 };
 857
 858 #ifdef CONFIG_SND_CTL_VALIDATION
 859 /* fill the remaining snd_ctl_elem_value data with the given pattern */
 860 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 861                                       struct snd_ctl_elem_info *info,
 862                                       u32 pattern)
 863 {
 864         size_t offset = value_sizes[info->type] * info->count;
 865
 866         offset = DIV_ROUND_UP(offset, sizeof(u32));
 867         memset32((u32 *)control->value.bytes.data + offset, pattern,
 868                  sizeof(control->value) / sizeof(u32) - offset);
 869 }
 870
 871 /* check whether the given integer ctl value is valid */
 872 static int sanity_check_int_value(struct snd_card *card,
 873                                   const struct snd_ctl_elem_value *control,
 874                                   const struct snd_ctl_elem_info *info,
 875                                   int i)
 876 {
 877         long long lval, lmin, lmax, lstep;
 878         u64 rem;
 879
 880         switch (info->type) {
 881         default:
 882         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 883                 lval = control->value.integer.value[i];
 884                 lmin = 0;
 885                 lmax = 1;
 886                 lstep = 0;
 887                 break;
 888         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 889                 lval = control->value.integer.value[i];
 890                 lmin = info->value.integer.min;
 891                 lmax = info->value.integer.max;
 892                 lstep = info->value.integer.step;
 893                 break;
 894         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 895                 lval = control->value.integer64.value[i];
 896                 lmin = info->value.integer64.min;
 897                 lmax = info->value.integer64.max;
 898                 lstep = info->value.integer64.step;
 899                 break;
 900         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 901                 lval = control->value.enumerated.item[i];
 902                 lmin = 0;
 903                 lmax = info->value.enumerated.items - 1;
 904                 lstep = 0;
 905                 break;
 906         }
 907
 908         if (lval < lmin || lval > lmax) {
 909                 dev_err(card->dev,
 910                         "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
 911                         control->id.iface, control->id.device,
 912                         control->id.subdevice, control->id.name,
 913                         control->id.index, lval, lmin, lmax, i);
 914                 return -EINVAL;
 915         }
 916         if (lstep) {
 917                 div64_u64_rem(lval, lstep, &rem);
 918                 if (rem) {
 919                         dev_err(card->dev,
 920                                 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
 921                                 control->id.iface, control->id.device,
 922                                 control->id.subdevice, control->id.name,
 923                                 control->id.index, lval, lstep, i);
 924                         return -EINVAL;
 925                 }
 926         }
 927
 928         return 0;
 929 }
 930
 931 /* perform sanity checks to the given snd_ctl_elem_value object */
 932 static int sanity_check_elem_value(struct snd_card *card,
 933                                    const struct snd_ctl_elem_value *control,
 934                                    const struct snd_ctl_elem_info *info,
 935                                    u32 pattern)
 936 {
 937         size_t offset;
 938         int i, ret = 0;
 939         u32 *p;
 940
 941         switch (info->type) {
 942         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 943         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 944         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 945         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 946                 for (i = 0; i < info->count; i++) {
 947                         ret = sanity_check_int_value(card, control, info, i);
 948                         if (ret < 0)
 949                                 return ret;
 950                 }
 951                 break;
 952         default:
 953                 break;
 954         }
 955
 956         /* check whether the remaining area kept untouched */
 957         offset = value_sizes[info->type] * info->count;
 958         offset = DIV_ROUND_UP(offset, sizeof(u32));
 959         p = (u32 *)control->value.bytes.data + offset;
 960         for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
 961                 if (*p != pattern) {
 962                         ret = -EINVAL;
 963                         break;
 964                 }
 965                 *p = 0; /* clear the checked area */
 966         }
 967
 968         return ret;
 969 }
 970 #else
 971 static inline void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 972                                              struct snd_ctl_elem_info *info,
 973                                              u32 pattern)
 974 {
 975 }
 976
 977 static inline int sanity_check_elem_value(struct snd_card *card,
 978                                           struct snd_ctl_elem_value *control,
 979                                           struct snd_ctl_elem_info *info,
 980                                           u32 pattern)
 981 {
 982         return 0;
 983 }
 984 #endif
 985
 986 static int __snd_ctl_elem_info(struct snd_card *card,
 987                                struct snd_kcontrol *kctl,
 988                                struct snd_ctl_elem_info *info,
 989                                struct snd_ctl_file *ctl)
 990 {
 991         struct snd_kcontrol_volatile *vd;
 992         unsigned int index_offset;
 993         int result;
 994
 995 #ifdef CONFIG_SND_DEBUG
 996         info->access = 0;
 997 #endif
 998         result = kctl->info(kctl, info);
 999         if (result >= 0) {
1000                 snd_BUG_ON(info->access);
1001                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
1002                 vd = &kctl->vd[index_offset];
1003                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
1004                 info->access = vd->access;
1005                 if (vd->owner) {
1006                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
1007                         if (vd->owner == ctl)
1008                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
1009                         info->owner = pid_vnr(vd->owner->pid);
1010                 } else {
1011                         info->owner = -1;
1012                 }
1013                 if (!snd_ctl_skip_validation(info) &&
1014                     snd_ctl_check_elem_info(card, info) < 0)
1015                         result = -EINVAL;
1016         }
1017         return result;
1018 }
1019
1020 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
1021                              struct snd_ctl_elem_info *info)
1022 {
1023         struct snd_card *card = ctl->card;
1024         struct snd_kcontrol *kctl;
1025         int result;
1026
1027         down_read(&card->controls_rwsem);
1028         kctl = snd_ctl_find_id(card, &info->id);
1029         if (kctl == NULL)
1030                 result = -ENOENT;
1031         else
1032                 result = __snd_ctl_elem_info(card, kctl, info, ctl);
1033         up_read(&card->controls_rwsem);
1034         return result;
1035 }
1036
1037 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1038                                   struct snd_ctl_elem_info __user *_info)
1039 {
1040         struct snd_ctl_elem_info info;
1041         int result;
1042
1043         if (copy_from_user(&info, _info, sizeof(info)))
1044                 return -EFAULT;
1045         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
1046         if (result < 0)
1047                 return result;
1048         result = snd_ctl_elem_info(ctl, &info);
1049         if (result < 0)
1050                 return result;
1051         /* drop internal access flags */
1052         info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
1053                          SNDRV_CTL_ELEM_ACCESS_LED_MASK);
1054         if (copy_to_user(_info, &info, sizeof(info)))
1055                 return -EFAULT;
1056         return result;
1057 }
1058
1059 static int snd_ctl_elem_read(struct snd_card *card,
1060                              struct snd_ctl_elem_value *control)
1061 {
1062         struct snd_kcontrol *kctl;
1063         struct snd_kcontrol_volatile *vd;
1064         unsigned int index_offset;
1065         struct snd_ctl_elem_info info;
1066         const u32 pattern = 0xdeadbeef;
1067         int ret;
1068
1069         kctl = snd_ctl_find_id(card, &control->id);
1070         if (kctl == NULL)
1071                 return -ENOENT;
1072
1073         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1074         vd = &kctl->vd[index_offset];
1075         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1076                 return -EPERM;
1077
1078         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1079
1080 #ifdef CONFIG_SND_CTL_VALIDATION
1081         /* info is needed only for validation */
1082         memset(&info, 0, sizeof(info));
1083         info.id = control->id;
1084         ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1085         if (ret < 0)
1086                 return ret;
1087 #endif
1088
1089         if (!snd_ctl_skip_validation(&info))
1090                 fill_remaining_elem_value(control, &info, pattern);
1091         ret = kctl->get(kctl, control);
1092         if (ret < 0)
1093                 return ret;
1094         if (!snd_ctl_skip_validation(&info) &&
1095             sanity_check_elem_value(card, control, &info, pattern) < 0) {
1096                 dev_err(card->dev,
1097                         "control %i:%i:%i:%s:%i: access overflow\n",
1098                         control->id.iface, control->id.device,
1099                         control->id.subdevice, control->id.name,
1100                         control->id.index);
1101                 return -EINVAL;
1102         }
1103         return ret;
1104 }
1105
1106 static int snd_ctl_elem_read_user(struct snd_card *card,
1107                                   struct snd_ctl_elem_value __user *_control)
1108 {
1109         struct snd_ctl_elem_value *control;
1110         int result;
1111
1112         control = memdup_user(_control, sizeof(*control));
1113         if (IS_ERR(control))
1114                 return PTR_ERR(control);
1115
1116         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1117         if (result < 0)
1118                 goto error;
1119
1120         down_read(&card->controls_rwsem);
1121         result = snd_ctl_elem_read(card, control);
1122         up_read(&card->controls_rwsem);
1123         if (result < 0)
1124                 goto error;
1125
1126         if (copy_to_user(_control, control, sizeof(*control)))
1127                 result = -EFAULT;
1128  error:
1129         kfree(control);
1130         return result;
1131 }
1132
1133 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1134                               struct snd_ctl_elem_value *control)
1135 {
1136         struct snd_kcontrol *kctl;
1137         struct snd_kcontrol_volatile *vd;
1138         unsigned int index_offset;
1139         int result;
1140
1141         down_write(&card->controls_rwsem);
1142         kctl = snd_ctl_find_id(card, &control->id);
1143         if (kctl == NULL) {
1144                 up_write(&card->controls_rwsem);
1145                 return -ENOENT;
1146         }
1147
1148         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1149         vd = &kctl->vd[index_offset];
1150         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1151             (file && vd->owner && vd->owner != file)) {
1152                 up_write(&card->controls_rwsem);
1153                 return -EPERM;
1154         }
1155
1156         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1157         result = kctl->put(kctl, control);
1158         if (result < 0) {
1159                 up_write(&card->controls_rwsem);
1160                 return result;
1161         }
1162
1163         if (result > 0) {
1164                 downgrade_write(&card->controls_rwsem);
1165                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
1166                 up_read(&card->controls_rwsem);
1167         } else {
1168                 up_write(&card->controls_rwsem);
1169         }
1170
1171         return 0;
1172 }
1173
1174 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1175                                    struct snd_ctl_elem_value __user *_control)
1176 {
1177         struct snd_ctl_elem_value *control;
1178         struct snd_card *card;
1179         int result;
1180
1181         control = memdup_user(_control, sizeof(*control));
1182         if (IS_ERR(control))
1183                 return PTR_ERR(control);
1184
1185         card = file->card;
1186         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1187         if (result < 0)
1188                 goto error;
1189
1190         result = snd_ctl_elem_write(card, file, control);
1191         if (result < 0)
1192                 goto error;
1193
1194         if (copy_to_user(_control, control, sizeof(*control)))
1195                 result = -EFAULT;
1196  error:
1197         kfree(control);
1198         return result;
1199 }
1200
1201 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1202                              struct snd_ctl_elem_id __user *_id)
1203 {
1204         struct snd_card *card = file->card;
1205         struct snd_ctl_elem_id id;
1206         struct snd_kcontrol *kctl;
1207         struct snd_kcontrol_volatile *vd;
1208         int result;
1209
1210         if (copy_from_user(&id, _id, sizeof(id)))
1211                 return -EFAULT;
1212         down_write(&card->controls_rwsem);
1213         kctl = snd_ctl_find_id(card, &id);
1214         if (kctl == NULL) {
1215                 result = -ENOENT;
1216         } else {
1217                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1218                 if (vd->owner != NULL)
1219                         result = -EBUSY;
1220                 else {
1221                         vd->owner = file;
1222                         result = 0;
1223                 }
1224         }
1225         up_write(&card->controls_rwsem);
1226         return result;
1227 }
1228
1229 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1230                                struct snd_ctl_elem_id __user *_id)
1231 {
1232         struct snd_card *card = file->card;
1233         struct snd_ctl_elem_id id;
1234         struct snd_kcontrol *kctl;
1235         struct snd_kcontrol_volatile *vd;
1236         int result;
1237
1238         if (copy_from_user(&id, _id, sizeof(id)))
1239                 return -EFAULT;
1240         down_write(&card->controls_rwsem);
1241         kctl = snd_ctl_find_id(card, &id);
1242         if (kctl == NULL) {
1243                 result = -ENOENT;
1244         } else {
1245                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1246                 if (vd->owner == NULL)
1247                         result = -EINVAL;
1248                 else if (vd->owner != file)
1249                         result = -EPERM;
1250                 else {
1251                         vd->owner = NULL;
1252                         result = 0;
1253                 }
1254         }
1255         up_write(&card->controls_rwsem);
1256         return result;
1257 }
1258
1259 struct user_element {
1260         struct snd_ctl_elem_info info;
1261         struct snd_card *card;
1262         char *elem_data;                /* element data */
1263         unsigned long elem_data_size;   /* size of element data in bytes */
1264         void *tlv_data;                 /* TLV data */
1265         unsigned long tlv_data_size;    /* TLV data size */
1266         void *priv_data;                /* private data (like strings for enumerated type) */
1267 };
1268
1269 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1270 static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
1271 {
1272         return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
1273 }
1274
1275 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1276                                   struct snd_ctl_elem_info *uinfo)
1277 {
1278         struct user_element *ue = kcontrol->private_data;
1279         unsigned int offset;
1280
1281         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1282         *uinfo = ue->info;
1283         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1284
1285         return 0;
1286 }
1287
1288 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1289                                        struct snd_ctl_elem_info *uinfo)
1290 {
1291         struct user_element *ue = kcontrol->private_data;
1292         const char *names;
1293         unsigned int item;
1294         unsigned int offset;
1295
1296         item = uinfo->value.enumerated.item;
1297
1298         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1299         *uinfo = ue->info;
1300         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1301
1302         item = min(item, uinfo->value.enumerated.items - 1);
1303         uinfo->value.enumerated.item = item;
1304
1305         names = ue->priv_data;
1306         for (; item > 0; --item)
1307                 names += strlen(names) + 1;
1308         strcpy(uinfo->value.enumerated.name, names);
1309
1310         return 0;
1311 }
1312
1313 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1314                                  struct snd_ctl_elem_value *ucontrol)
1315 {
1316         struct user_element *ue = kcontrol->private_data;
1317         unsigned int size = ue->elem_data_size;
1318         char *src = ue->elem_data +
1319                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1320
1321         memcpy(&ucontrol->value, src, size);
1322         return 0;
1323 }
1324
1325 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1326                                  struct snd_ctl_elem_value *ucontrol)
1327 {
1328         int change;
1329         struct user_element *ue = kcontrol->private_data;
1330         unsigned int size = ue->elem_data_size;
1331         char *dst = ue->elem_data +
1332                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1333
1334         change = memcmp(&ucontrol->value, dst, size) != 0;
1335         if (change)
1336                 memcpy(dst, &ucontrol->value, size);
1337         return change;
1338 }
1339
1340 /* called in controls_rwsem write lock */
1341 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1342                             unsigned int size)
1343 {
1344         struct user_element *ue = kctl->private_data;
1345         unsigned int *container;
1346         unsigned int mask = 0;
1347         int i;
1348         int change;
1349
1350         if (size > 1024 * 128)  /* sane value */
1351                 return -EINVAL;
1352
1353         // does the TLV size change cause overflow?
1354         if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
1355                 return -ENOMEM;
1356
1357         container = vmemdup_user(buf, size);
1358         if (IS_ERR(container))
1359                 return PTR_ERR(container);
1360
1361         change = ue->tlv_data_size != size;
1362         if (!change)
1363                 change = memcmp(ue->tlv_data, container, size) != 0;
1364         if (!change) {
1365                 kvfree(container);
1366                 return 0;
1367         }
1368
1369         if (ue->tlv_data == NULL) {
1370                 /* Now TLV data is available. */
1371                 for (i = 0; i < kctl->count; ++i)
1372                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1373                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1374         } else {
1375                 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1376                 ue->tlv_data_size = 0;
1377                 kvfree(ue->tlv_data);
1378         }
1379
1380         ue->tlv_data = container;
1381         ue->tlv_data_size = size;
1382         // decremented at private_free.
1383         ue->card->user_ctl_alloc_size += size;
1384
1385         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1386         for (i = 0; i < kctl->count; ++i)
1387                 snd_ctl_notify_one(ue->card, mask, kctl, i);
1388
1389         return change;
1390 }
1391
1392 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1393                          unsigned int size)
1394 {
1395         struct user_element *ue = kctl->private_data;
1396
1397         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1398                 return -ENXIO;
1399
1400         if (size < ue->tlv_data_size)
1401                 return -ENOSPC;
1402
1403         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1404                 return -EFAULT;
1405
1406         return 0;
1407 }
1408
1409 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1410                                  unsigned int size, unsigned int __user *buf)
1411 {
1412         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1413                 return replace_user_tlv(kctl, buf, size);
1414         else
1415                 return read_user_tlv(kctl, buf, size);
1416 }
1417
1418 /* called in controls_rwsem write lock */
1419 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1420 {
1421         char *names, *p;
1422         size_t buf_len, name_len;
1423         unsigned int i;
1424         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1425
1426         buf_len = ue->info.value.enumerated.names_length;
1427         if (buf_len > 64 * 1024)
1428                 return -EINVAL;
1429
1430         if (check_user_elem_overflow(ue->card, buf_len))
1431                 return -ENOMEM;
1432         names = vmemdup_user((const void __user *)user_ptrval, buf_len);
1433         if (IS_ERR(names))
1434                 return PTR_ERR(names);
1435
1436         /* check that there are enough valid names */
1437         p = names;
1438         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1439                 name_len = strnlen(p, buf_len);
1440                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1441                         kvfree(names);
1442                         return -EINVAL;
1443                 }
1444                 p += name_len + 1;
1445                 buf_len -= name_len + 1;
1446         }
1447
1448         ue->priv_data = names;
1449         ue->info.value.enumerated.names_ptr = 0;
1450         // increment the allocation size; decremented again at private_free.
1451         ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
1452
1453         return 0;
1454 }
1455
1456 static size_t compute_user_elem_size(size_t size, unsigned int count)
1457 {
1458         return sizeof(struct user_element) + size * count;
1459 }
1460
1461 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1462 {
1463         struct user_element *ue = kcontrol->private_data;
1464
1465         // decrement the allocation size.
1466         ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
1467         ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1468         if (ue->priv_data)
1469                 ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
1470
1471         kvfree(ue->tlv_data);
1472         kvfree(ue->priv_data);
1473         kfree(ue);
1474 }
1475
1476 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1477                             struct snd_ctl_elem_info *info, int replace)
1478 {
1479         struct snd_card *card = file->card;
1480         struct snd_kcontrol *kctl;
1481         unsigned int count;
1482         unsigned int access;
1483         long private_size;
1484         size_t alloc_size;
1485         struct user_element *ue;
1486         unsigned int offset;
1487         int err;
1488
1489         if (!*info->id.name)
1490                 return -EINVAL;
1491         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1492                 return -EINVAL;
1493
1494         /* Delete a control to replace them if needed. */
1495         if (replace) {
1496                 info->id.numid = 0;
1497                 err = snd_ctl_remove_user_ctl(file, &info->id);
1498                 if (err)
1499                         return err;
1500         }
1501
1502         /* Check the number of elements for this userspace control. */
1503         count = info->owner;
1504         if (count == 0)
1505                 count = 1;
1506
1507         /* Arrange access permissions if needed. */
1508         access = info->access;
1509         if (access == 0)
1510                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1511         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1512                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1513                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1514
1515         /* In initial state, nothing is available as TLV container. */
1516         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1517                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1518         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1519
1520         /*
1521          * Check information and calculate the size of data specific to
1522          * this userspace control.
1523          */
1524         /* pass NULL to card for suppressing error messages */
1525         err = snd_ctl_check_elem_info(NULL, info);
1526         if (err < 0)
1527                 return err;
1528         /* user-space control doesn't allow zero-size data */
1529         if (info->count < 1)
1530                 return -EINVAL;
1531         private_size = value_sizes[info->type] * info->count;
1532         alloc_size = compute_user_elem_size(private_size, count);
1533
1534         down_write(&card->controls_rwsem);
1535         if (check_user_elem_overflow(card, alloc_size)) {
1536                 err = -ENOMEM;
1537                 goto unlock;
1538         }
1539
1540         /*
1541          * Keep memory object for this userspace control. After passing this
1542          * code block, the instance should be freed by snd_ctl_free_one().
1543          *
1544          * Note that these elements in this control are locked.
1545          */
1546         err = snd_ctl_new(&kctl, count, access, file);
1547         if (err < 0)
1548                 goto unlock;
1549         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1550         ue = kzalloc(alloc_size, GFP_KERNEL);
1551         if (!ue) {
1552                 kfree(kctl);
1553                 err = -ENOMEM;
1554                 goto unlock;
1555         }
1556         kctl->private_data = ue;
1557         kctl->private_free = snd_ctl_elem_user_free;
1558
1559         // increment the allocated size; decremented again at private_free.
1560         card->user_ctl_alloc_size += alloc_size;
1561
1562         /* Set private data for this userspace control. */
1563         ue->card = card;
1564         ue->info = *info;
1565         ue->info.access = 0;
1566         ue->elem_data = (char *)ue + sizeof(*ue);
1567         ue->elem_data_size = private_size;
1568         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1569                 err = snd_ctl_elem_init_enum_names(ue);
1570                 if (err < 0) {
1571                         snd_ctl_free_one(kctl);
1572                         goto unlock;
1573                 }
1574         }
1575
1576         /* Set callback functions. */
1577         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1578                 kctl->info = snd_ctl_elem_user_enum_info;
1579         else
1580                 kctl->info = snd_ctl_elem_user_info;
1581         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1582                 kctl->get = snd_ctl_elem_user_get;
1583         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1584                 kctl->put = snd_ctl_elem_user_put;
1585         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1586                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1587
1588         /* This function manage to free the instance on failure. */
1589         err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1590         if (err < 0) {
1591                 snd_ctl_free_one(kctl);
1592                 goto unlock;
1593         }
1594         offset = snd_ctl_get_ioff(kctl, &info->id);
1595         snd_ctl_build_ioff(&info->id, kctl, offset);
1596         /*
1597          * Here we cannot fill any field for the number of elements added by
1598          * this operation because there're no specific fields. The usage of
1599          * 'owner' field for this purpose may cause any bugs to userspace
1600          * applications because the field originally means PID of a process
1601          * which locks the element.
1602          */
1603  unlock:
1604         up_write(&card->controls_rwsem);
1605         return err;
1606 }
1607
1608 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1609                                  struct snd_ctl_elem_info __user *_info, int replace)
1610 {
1611         struct snd_ctl_elem_info info;
1612         int err;
1613
1614         if (copy_from_user(&info, _info, sizeof(info)))
1615                 return -EFAULT;
1616         err = snd_ctl_elem_add(file, &info, replace);
1617         if (err < 0)
1618                 return err;
1619         if (copy_to_user(_info, &info, sizeof(info))) {
1620                 snd_ctl_remove_user_ctl(file, &info.id);
1621                 return -EFAULT;
1622         }
1623
1624         return 0;
1625 }
1626
1627 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1628                                struct snd_ctl_elem_id __user *_id)
1629 {
1630         struct snd_ctl_elem_id id;
1631
1632         if (copy_from_user(&id, _id, sizeof(id)))
1633                 return -EFAULT;
1634         return snd_ctl_remove_user_ctl(file, &id);
1635 }
1636
1637 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1638 {
1639         int subscribe;
1640         if (get_user(subscribe, ptr))
1641                 return -EFAULT;
1642         if (subscribe < 0) {
1643                 subscribe = file->subscribed;
1644                 if (put_user(subscribe, ptr))
1645                         return -EFAULT;
1646                 return 0;
1647         }
1648         if (subscribe) {
1649                 file->subscribed = 1;
1650                 return 0;
1651         } else if (file->subscribed) {
1652                 snd_ctl_empty_read_queue(file);
1653                 file->subscribed = 0;
1654         }
1655         return 0;
1656 }
1657
1658 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1659                             struct snd_kcontrol *kctl,
1660                             struct snd_ctl_elem_id *id,
1661                             unsigned int __user *buf, unsigned int size)
1662 {
1663         static const struct {
1664                 int op;
1665                 int perm;
1666         } pairs[] = {
1667                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1668                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1669                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1670         };
1671         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1672         int i;
1673
1674         /* Check support of the request for this element. */
1675         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1676                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1677                         break;
1678         }
1679         if (i == ARRAY_SIZE(pairs))
1680                 return -ENXIO;
1681
1682         if (kctl->tlv.c == NULL)
1683                 return -ENXIO;
1684
1685         /* Write and command operations are not allowed for locked element. */
1686         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1687             vd->owner != NULL && vd->owner != file)
1688                 return -EPERM;
1689
1690         return kctl->tlv.c(kctl, op_flag, size, buf);
1691 }
1692
1693 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1694                         unsigned int __user *buf, unsigned int size)
1695 {
1696         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1697         unsigned int len;
1698
1699         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1700                 return -ENXIO;
1701
1702         if (kctl->tlv.p == NULL)
1703                 return -ENXIO;
1704
1705         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1706         if (size < len)
1707                 return -ENOMEM;
1708
1709         if (copy_to_user(buf, kctl->tlv.p, len))
1710                 return -EFAULT;
1711
1712         return 0;
1713 }
1714
1715 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1716                              struct snd_ctl_tlv __user *buf,
1717                              int op_flag)
1718 {
1719         struct snd_ctl_tlv header;
1720         unsigned int __user *container;
1721         unsigned int container_size;
1722         struct snd_kcontrol *kctl;
1723         struct snd_ctl_elem_id id;
1724         struct snd_kcontrol_volatile *vd;
1725
1726         if (copy_from_user(&header, buf, sizeof(header)))
1727                 return -EFAULT;
1728
1729         /* In design of control core, numerical ID starts at 1. */
1730         if (header.numid == 0)
1731                 return -EINVAL;
1732
1733         /* At least, container should include type and length fields.  */
1734         if (header.length < sizeof(unsigned int) * 2)
1735                 return -EINVAL;
1736         container_size = header.length;
1737         container = buf->tlv;
1738
1739         kctl = snd_ctl_find_numid(file->card, header.numid);
1740         if (kctl == NULL)
1741                 return -ENOENT;
1742
1743         /* Calculate index of the element in this set. */
1744         id = kctl->id;
1745         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1746         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1747
1748         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1749                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1750                                         container_size);
1751         } else {
1752                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1753                         return read_tlv_buf(kctl, &id, container,
1754                                             container_size);
1755                 }
1756         }
1757
1758         /* Not supported. */
1759         return -ENXIO;
1760 }
1761
1762 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1763 {
1764         struct snd_ctl_file *ctl;
1765         struct snd_card *card;
1766         struct snd_kctl_ioctl *p;
1767         void __user *argp = (void __user *)arg;
1768         int __user *ip = argp;
1769         int err;
1770
1771         ctl = file->private_data;
1772         card = ctl->card;
1773         if (snd_BUG_ON(!card))
1774                 return -ENXIO;
1775         switch (cmd) {
1776         case SNDRV_CTL_IOCTL_PVERSION:
1777                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1778         case SNDRV_CTL_IOCTL_CARD_INFO:
1779                 return snd_ctl_card_info(card, ctl, cmd, argp);
1780         case SNDRV_CTL_IOCTL_ELEM_LIST:
1781                 return snd_ctl_elem_list_user(card, argp);
1782         case SNDRV_CTL_IOCTL_ELEM_INFO:
1783                 return snd_ctl_elem_info_user(ctl, argp);
1784         case SNDRV_CTL_IOCTL_ELEM_READ:
1785                 return snd_ctl_elem_read_user(card, argp);
1786         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1787                 return snd_ctl_elem_write_user(ctl, argp);
1788         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1789                 return snd_ctl_elem_lock(ctl, argp);
1790         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1791                 return snd_ctl_elem_unlock(ctl, argp);
1792         case SNDRV_CTL_IOCTL_ELEM_ADD:
1793                 return snd_ctl_elem_add_user(ctl, argp, 0);
1794         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1795                 return snd_ctl_elem_add_user(ctl, argp, 1);
1796         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1797                 return snd_ctl_elem_remove(ctl, argp);
1798         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1799                 return snd_ctl_subscribe_events(ctl, ip);
1800         case SNDRV_CTL_IOCTL_TLV_READ:
1801                 down_read(&ctl->card->controls_rwsem);
1802                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1803                 up_read(&ctl->card->controls_rwsem);
1804                 return err;
1805         case SNDRV_CTL_IOCTL_TLV_WRITE:
1806                 down_write(&ctl->card->controls_rwsem);
1807                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1808                 up_write(&ctl->card->controls_rwsem);
1809                 return err;
1810         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1811                 down_write(&ctl->card->controls_rwsem);
1812                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1813                 up_write(&ctl->card->controls_rwsem);
1814                 return err;
1815         case SNDRV_CTL_IOCTL_POWER:
1816                 return -ENOPROTOOPT;
1817         case SNDRV_CTL_IOCTL_POWER_STATE:
1818 #ifdef CONFIG_PM
1819                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1820 #else
1821                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1822 #endif
1823         }
1824         down_read(&snd_ioctl_rwsem);
1825         list_for_each_entry(p, &snd_control_ioctls, list) {
1826                 err = p->fioctl(card, ctl, cmd, arg);
1827                 if (err != -ENOIOCTLCMD) {
1828                         up_read(&snd_ioctl_rwsem);
1829                         return err;
1830                 }
1831         }
1832         up_read(&snd_ioctl_rwsem);
1833         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1834         return -ENOTTY;
1835 }
1836
1837 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1838                             size_t count, loff_t * offset)
1839 {
1840         struct snd_ctl_file *ctl;
1841         int err = 0;
1842         ssize_t result = 0;
1843
1844         ctl = file->private_data;
1845         if (snd_BUG_ON(!ctl || !ctl->card))
1846                 return -ENXIO;
1847         if (!ctl->subscribed)
1848                 return -EBADFD;
1849         if (count < sizeof(struct snd_ctl_event))
1850                 return -EINVAL;
1851         spin_lock_irq(&ctl->read_lock);
1852         while (count >= sizeof(struct snd_ctl_event)) {
1853                 struct snd_ctl_event ev;
1854                 struct snd_kctl_event *kev;
1855                 while (list_empty(&ctl->events)) {
1856                         wait_queue_entry_t wait;
1857                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1858                                 err = -EAGAIN;
1859                                 goto __end_lock;
1860                         }
1861                         init_waitqueue_entry(&wait, current);
1862                         add_wait_queue(&ctl->change_sleep, &wait);
1863                         set_current_state(TASK_INTERRUPTIBLE);
1864                         spin_unlock_irq(&ctl->read_lock);
1865                         schedule();
1866                         remove_wait_queue(&ctl->change_sleep, &wait);
1867                         if (ctl->card->shutdown)
1868                                 return -ENODEV;
1869                         if (signal_pending(current))
1870                                 return -ERESTARTSYS;
1871                         spin_lock_irq(&ctl->read_lock);
1872                 }
1873                 kev = snd_kctl_event(ctl->events.next);
1874                 ev.type = SNDRV_CTL_EVENT_ELEM;
1875                 ev.data.elem.mask = kev->mask;
1876                 ev.data.elem.id = kev->id;
1877                 list_del(&kev->list);
1878                 spin_unlock_irq(&ctl->read_lock);
1879                 kfree(kev);
1880                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1881                         err = -EFAULT;
1882                         goto __end;
1883                 }
1884                 spin_lock_irq(&ctl->read_lock);
1885                 buffer += sizeof(struct snd_ctl_event);
1886                 count -= sizeof(struct snd_ctl_event);
1887                 result += sizeof(struct snd_ctl_event);
1888         }
1889       __end_lock:
1890         spin_unlock_irq(&ctl->read_lock);
1891       __end:
1892         return result > 0 ? result : err;
1893 }
1894
1895 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1896 {
1897         __poll_t mask;
1898         struct snd_ctl_file *ctl;
1899
1900         ctl = file->private_data;
1901         if (!ctl->subscribed)
1902                 return 0;
1903         poll_wait(file, &ctl->change_sleep, wait);
1904
1905         mask = 0;
1906         if (!list_empty(&ctl->events))
1907                 mask |= EPOLLIN | EPOLLRDNORM;
1908
1909         return mask;
1910 }
1911
1912 /*
1913  * register the device-specific control-ioctls.
1914  * called from each device manager like pcm.c, hwdep.c, etc.
1915  */
1916 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1917 {
1918         struct snd_kctl_ioctl *pn;
1919
1920         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1921         if (pn == NULL)
1922                 return -ENOMEM;
1923         pn->fioctl = fcn;
1924         down_write(&snd_ioctl_rwsem);
1925         list_add_tail(&pn->list, lists);
1926         up_write(&snd_ioctl_rwsem);
1927         return 0;
1928 }
1929
1930 /**
1931  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1932  * @fcn: ioctl callback function
1933  *
1934  * called from each device manager like pcm.c, hwdep.c, etc.
1935  */
1936 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1937 {
1938         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1939 }
1940 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1941
1942 #ifdef CONFIG_COMPAT
1943 /**
1944  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1945  * control-ioctls
1946  * @fcn: ioctl callback function
1947  */
1948 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1949 {
1950         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1951 }
1952 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1953 #endif
1954
1955 /*
1956  * de-register the device-specific control-ioctls.
1957  */
1958 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1959                                      struct list_head *lists)
1960 {
1961         struct snd_kctl_ioctl *p;
1962
1963         if (snd_BUG_ON(!fcn))
1964                 return -EINVAL;
1965         down_write(&snd_ioctl_rwsem);
1966         list_for_each_entry(p, lists, list) {
1967                 if (p->fioctl == fcn) {
1968                         list_del(&p->list);
1969                         up_write(&snd_ioctl_rwsem);
1970                         kfree(p);
1971                         return 0;
1972                 }
1973         }
1974         up_write(&snd_ioctl_rwsem);
1975         snd_BUG();
1976         return -EINVAL;
1977 }
1978
1979 /**
1980  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1981  * @fcn: ioctl callback function to unregister
1982  */
1983 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1984 {
1985         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1986 }
1987 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1988
1989 #ifdef CONFIG_COMPAT
1990 /**
1991  * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
1992  * 32bit control-ioctls
1993  * @fcn: ioctl callback function to unregister
1994  */
1995 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1996 {
1997         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1998 }
1999 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
2000 #endif
2001
2002 static int snd_ctl_fasync(int fd, struct file * file, int on)
2003 {
2004         struct snd_ctl_file *ctl;
2005
2006         ctl = file->private_data;
2007         return fasync_helper(fd, file, on, &ctl->fasync);
2008 }
2009
2010 /* return the preferred subdevice number if already assigned;
2011  * otherwise return -1
2012  */
2013 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
2014 {
2015         struct snd_ctl_file *kctl;
2016         int subdevice = -1;
2017         unsigned long flags;
2018
2019         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2020         list_for_each_entry(kctl, &card->ctl_files, list) {
2021                 if (kctl->pid == task_pid(current)) {
2022                         subdevice = kctl->preferred_subdevice[type];
2023                         if (subdevice != -1)
2024                                 break;
2025                 }
2026         }
2027         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2028         return subdevice;
2029 }
2030 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
2031
2032 /*
2033  * ioctl32 compat
2034  */
2035 #ifdef CONFIG_COMPAT
2036 #include "control_compat.c"
2037 #else
2038 #define snd_ctl_ioctl_compat    NULL
2039 #endif
2040
2041 /*
2042  * control layers (audio LED etc.)
2043  */
2044
2045 /**
2046  * snd_ctl_request_layer - request to use the layer
2047  * @module_name: Name of the kernel module (NULL == build-in)
2048  *
2049  * Return an error code when the module cannot be loaded.
2050  */
2051 int snd_ctl_request_layer(const char *module_name)
2052 {
2053         struct snd_ctl_layer_ops *lops;
2054
2055         if (module_name == NULL)
2056                 return 0;
2057         down_read(&snd_ctl_layer_rwsem);
2058         for (lops = snd_ctl_layer; lops; lops = lops->next)
2059                 if (strcmp(lops->module_name, module_name) == 0)
2060                         break;
2061         up_read(&snd_ctl_layer_rwsem);
2062         if (lops)
2063                 return 0;
2064         return request_module(module_name);
2065 }
2066 EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
2067
2068 /**
2069  * snd_ctl_register_layer - register new control layer
2070  * @lops: operation structure
2071  *
2072  * The new layer can track all control elements and do additional
2073  * operations on top (like audio LED handling).
2074  */
2075 void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
2076 {
2077         struct snd_card *card;
2078         int card_number;
2079
2080         down_write(&snd_ctl_layer_rwsem);
2081         lops->next = snd_ctl_layer;
2082         snd_ctl_layer = lops;
2083         up_write(&snd_ctl_layer_rwsem);
2084         for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
2085                 card = snd_card_ref(card_number);
2086                 if (card) {
2087                         down_read(&card->controls_rwsem);
2088                         lops->lregister(card);
2089                         up_read(&card->controls_rwsem);
2090                         snd_card_unref(card);
2091                 }
2092         }
2093 }
2094 EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
2095
2096 /**
2097  * snd_ctl_disconnect_layer - disconnect control layer
2098  * @lops: operation structure
2099  *
2100  * It is expected that the information about tracked cards
2101  * is freed before this call (the disconnect callback is
2102  * not called here).
2103  */
2104 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
2105 {
2106         struct snd_ctl_layer_ops *lops2, *prev_lops2;
2107
2108         down_write(&snd_ctl_layer_rwsem);
2109         for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
2110                 if (lops2 == lops) {
2111                         if (!prev_lops2)
2112                                 snd_ctl_layer = lops->next;
2113                         else
2114                                 prev_lops2->next = lops->next;
2115                         break;
2116                 }
2117                 prev_lops2 = lops2;
2118         }
2119         up_write(&snd_ctl_layer_rwsem);
2120 }
2121 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
2122
2123 /*
2124  *  INIT PART
2125  */
2126
2127 static const struct file_operations snd_ctl_f_ops =
2128 {
2129         .owner =        THIS_MODULE,
2130         .read =         snd_ctl_read,
2131         .open =         snd_ctl_open,
2132         .release =      snd_ctl_release,
2133         .llseek =       no_llseek,
2134         .poll =         snd_ctl_poll,
2135         .unlocked_ioctl =       snd_ctl_ioctl,
2136         .compat_ioctl = snd_ctl_ioctl_compat,
2137         .fasync =       snd_ctl_fasync,
2138 };
2139
2140 /*
2141  * registration of the control device
2142  */
2143 static int snd_ctl_dev_register(struct snd_device *device)
2144 {
2145         struct snd_card *card = device->device_data;
2146         struct snd_ctl_layer_ops *lops;
2147         int err;
2148
2149         err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2150                                   &snd_ctl_f_ops, card, &card->ctl_dev);
2151         if (err < 0)
2152                 return err;
2153         down_read(&card->controls_rwsem);
2154         down_read(&snd_ctl_layer_rwsem);
2155         for (lops = snd_ctl_layer; lops; lops = lops->next)
2156                 lops->lregister(card);
2157         up_read(&snd_ctl_layer_rwsem);
2158         up_read(&card->controls_rwsem);
2159         return 0;
2160 }
2161
2162 /*
2163  * disconnection of the control device
2164  */
2165 static int snd_ctl_dev_disconnect(struct snd_device *device)
2166 {
2167         struct snd_card *card = device->device_data;
2168         struct snd_ctl_file *ctl;
2169         struct snd_ctl_layer_ops *lops;
2170         unsigned long flags;
2171
2172         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2173         list_for_each_entry(ctl, &card->ctl_files, list) {
2174                 wake_up(&ctl->change_sleep);
2175                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
2176         }
2177         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2178
2179         down_read(&card->controls_rwsem);
2180         down_read(&snd_ctl_layer_rwsem);
2181         for (lops = snd_ctl_layer; lops; lops = lops->next)
2182                 lops->ldisconnect(card);
2183         up_read(&snd_ctl_layer_rwsem);
2184         up_read(&card->controls_rwsem);
2185
2186         return snd_unregister_device(&card->ctl_dev);
2187 }
2188
2189 /*
2190  * free all controls
2191  */
2192 static int snd_ctl_dev_free(struct snd_device *device)
2193 {
2194         struct snd_card *card = device->device_data;
2195         struct snd_kcontrol *control;
2196
2197         down_write(&card->controls_rwsem);
2198         while (!list_empty(&card->controls)) {
2199                 control = snd_kcontrol(card->controls.next);
2200                 snd_ctl_remove(card, control);
2201         }
2202         up_write(&card->controls_rwsem);
2203         put_device(&card->ctl_dev);
2204         return 0;
2205 }
2206
2207 /*
2208  * create control core:
2209  * called from init.c
2210  */
2211 int snd_ctl_create(struct snd_card *card)
2212 {
2213         static const struct snd_device_ops ops = {
2214                 .dev_free = snd_ctl_dev_free,
2215                 .dev_register = snd_ctl_dev_register,
2216                 .dev_disconnect = snd_ctl_dev_disconnect,
2217         };
2218         int err;
2219
2220         if (snd_BUG_ON(!card))
2221                 return -ENXIO;
2222         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2223                 return -ENXIO;
2224
2225         snd_device_initialize(&card->ctl_dev, card);
2226         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2227
2228         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2229         if (err < 0)
2230                 put_device(&card->ctl_dev);
2231         return err;
2232 }
2233
2234 /*
2235  * Frequently used control callbacks/helpers
2236  */
2237
2238 /**
2239  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2240  * callback with a mono channel
2241  * @kcontrol: the kcontrol instance
2242  * @uinfo: info to store
2243  *
2244  * This is a function that can be used as info callback for a standard
2245  * boolean control with a single mono channel.
2246  */
2247 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2248                               struct snd_ctl_elem_info *uinfo)
2249 {
2250         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2251         uinfo->count = 1;
2252         uinfo->value.integer.min = 0;
2253         uinfo->value.integer.max = 1;
2254         return 0;
2255 }
2256 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2257
2258 /**
2259  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2260  * callback with stereo two channels
2261  * @kcontrol: the kcontrol instance
2262  * @uinfo: info to store
2263  *
2264  * This is a function that can be used as info callback for a standard
2265  * boolean control with stereo two channels.
2266  */
2267 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2268                                 struct snd_ctl_elem_info *uinfo)
2269 {
2270         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2271         uinfo->count = 2;
2272         uinfo->value.integer.min = 0;
2273         uinfo->value.integer.max = 1;
2274         return 0;
2275 }
2276 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2277
2278 /**
2279  * snd_ctl_enum_info - fills the info structure for an enumerated control
2280  * @info: the structure to be filled
2281  * @channels: the number of the control's channels; often one
2282  * @items: the number of control values; also the size of @names
2283  * @names: an array containing the names of all control values
2284  *
2285  * Sets all required fields in @info to their appropriate values.
2286  * If the control's accessibility is not the default (readable and writable),
2287  * the caller has to fill @info->access.
2288  *
2289  * Return: Zero.
2290  */
2291 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2292                       unsigned int items, const char *const names[])
2293 {
2294         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2295         info->count = channels;
2296         info->value.enumerated.items = items;
2297         if (!items)
2298                 return 0;
2299         if (info->value.enumerated.item >= items)
2300                 info->value.enumerated.item = items - 1;
2301         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2302              "ALSA: too long item name '%s'\n",
2303              names[info->value.enumerated.item]);
2304         strscpy(info->value.enumerated.name,
2305                 names[info->value.enumerated.item],
2306                 sizeof(info->value.enumerated.name));
2307         return 0;
2308 }
2309 EXPORT_SYMBOL(snd_ctl_enum_info);