sound/core/control.c

   1 /*
   2  *  Routines for driver control interface
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/threads.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/time.h>
  28 #include <linux/mm.h>
  29 #include <linux/sched/signal.h>
  30 #include <sound/core.h>
  31 #include <sound/minors.h>
  32 #include <sound/info.h>
  33 #include <sound/control.h>
  34
  35 /* max number of user-defined controls */
  36 #define MAX_USER_CONTROLS       32
  37 #define MAX_CONTROL_COUNT       1028
  38
  39 struct snd_kctl_ioctl {
  40         struct list_head list;          /* list of all ioctls */
  41         snd_kctl_ioctl_func_t fioctl;
  42 };
  43
  44 static DECLARE_RWSEM(snd_ioctl_rwsem);
  45 static LIST_HEAD(snd_control_ioctls);
  46 #ifdef CONFIG_COMPAT
  47 static LIST_HEAD(snd_control_compat_ioctls);
  48 #endif
  49
  50 static int snd_ctl_open(struct inode *inode, struct file *file)
  51 {
  52         unsigned long flags;
  53         struct snd_card *card;
  54         struct snd_ctl_file *ctl;
  55         int i, err;
  56
  57         err = nonseekable_open(inode, file);
  58         if (err < 0)
  59                 return err;
  60
  61         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  62         if (!card) {
  63                 err = -ENODEV;
  64                 goto __error1;
  65         }
  66         err = snd_card_file_add(card, file);
  67         if (err < 0) {
  68                 err = -ENODEV;
  69                 goto __error1;
  70         }
  71         if (!try_module_get(card->module)) {
  72                 err = -EFAULT;
  73                 goto __error2;
  74         }
  75         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  76         if (ctl == NULL) {
  77                 err = -ENOMEM;
  78                 goto __error;
  79         }
  80         INIT_LIST_HEAD(&ctl->events);
  81         init_waitqueue_head(&ctl->change_sleep);
  82         spin_lock_init(&ctl->read_lock);
  83         ctl->card = card;
  84         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  85                 ctl->preferred_subdevice[i] = -1;
  86         ctl->pid = get_pid(task_pid(current));
  87         file->private_data = ctl;
  88         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  89         list_add_tail(&ctl->list, &card->ctl_files);
  90         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  91         snd_card_unref(card);
  92         return 0;
  93
  94       __error:
  95         module_put(card->module);
  96       __error2:
  97         snd_card_file_remove(card, file);
  98       __error1:
  99         if (card)
 100                 snd_card_unref(card);
 101         return err;
 102 }
 103
 104 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 105 {
 106         unsigned long flags;
 107         struct snd_kctl_event *cread;
 108
 109         spin_lock_irqsave(&ctl->read_lock, flags);
 110         while (!list_empty(&ctl->events)) {
 111                 cread = snd_kctl_event(ctl->events.next);
 112                 list_del(&cread->list);
 113                 kfree(cread);
 114         }
 115         spin_unlock_irqrestore(&ctl->read_lock, flags);
 116 }
 117
 118 static int snd_ctl_release(struct inode *inode, struct file *file)
 119 {
 120         unsigned long flags;
 121         struct snd_card *card;
 122         struct snd_ctl_file *ctl;
 123         struct snd_kcontrol *control;
 124         unsigned int idx;
 125
 126         ctl = file->private_data;
 127         file->private_data = NULL;
 128         card = ctl->card;
 129         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 130         list_del(&ctl->list);
 131         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 132         down_write(&card->controls_rwsem);
 133         list_for_each_entry(control, &card->controls, list)
 134                 for (idx = 0; idx < control->count; idx++)
 135                         if (control->vd[idx].owner == ctl)
 136                                 control->vd[idx].owner = NULL;
 137         up_write(&card->controls_rwsem);
 138         snd_ctl_empty_read_queue(ctl);
 139         put_pid(ctl->pid);
 140         kfree(ctl);
 141         module_put(card->module);
 142         snd_card_file_remove(card, file);
 143         return 0;
 144 }
 145
 146 /**
 147  * snd_ctl_notify - Send notification to user-space for a control change
 148  * @card: the card to send notification
 149  * @mask: the event mask, SNDRV_CTL_EVENT_*
 150  * @id: the ctl element id to send notification
 151  *
 152  * This function adds an event record with the given id and mask, appends
 153  * to the list and wakes up the user-space for notification.  This can be
 154  * called in the atomic context.
 155  */
 156 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 157                     struct snd_ctl_elem_id *id)
 158 {
 159         unsigned long flags;
 160         struct snd_ctl_file *ctl;
 161         struct snd_kctl_event *ev;
 162
 163         if (snd_BUG_ON(!card || !id))
 164                 return;
 165         if (card->shutdown)
 166                 return;
 167         read_lock(&card->ctl_files_rwlock);
 168 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 169         card->mixer_oss_change_count++;
 170 #endif
 171         list_for_each_entry(ctl, &card->ctl_files, list) {
 172                 if (!ctl->subscribed)
 173                         continue;
 174                 spin_lock_irqsave(&ctl->read_lock, flags);
 175                 list_for_each_entry(ev, &ctl->events, list) {
 176                         if (ev->id.numid == id->numid) {
 177                                 ev->mask |= mask;
 178                                 goto _found;
 179                         }
 180                 }
 181                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 182                 if (ev) {
 183                         ev->id = *id;
 184                         ev->mask = mask;
 185                         list_add_tail(&ev->list, &ctl->events);
 186                 } else {
 187                         dev_err(card->dev, "No memory available to allocate event\n");
 188                 }
 189         _found:
 190                 wake_up(&ctl->change_sleep);
 191                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 192                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 193         }
 194         read_unlock(&card->ctl_files_rwlock);
 195 }
 196 EXPORT_SYMBOL(snd_ctl_notify);
 197
 198 /**
 199  * snd_ctl_new - create a new control instance with some elements
 200  * @kctl: the pointer to store new control instance
 201  * @count: the number of elements in this control
 202  * @access: the default access flags for elements in this control
 203  * @file: given when locking these elements
 204  *
 205  * Allocates a memory object for a new control instance. The instance has
 206  * elements as many as the given number (@count). Each element has given
 207  * access permissions (@access). Each element is locked when @file is given.
 208  *
 209  * Return: 0 on success, error code on failure
 210  */
 211 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 212                        unsigned int access, struct snd_ctl_file *file)
 213 {
 214         unsigned int size;
 215         unsigned int idx;
 216
 217         if (count == 0 || count > MAX_CONTROL_COUNT)
 218                 return -EINVAL;
 219
 220         size  = sizeof(struct snd_kcontrol);
 221         size += sizeof(struct snd_kcontrol_volatile) * count;
 222
 223         *kctl = kzalloc(size, GFP_KERNEL);
 224         if (!*kctl)
 225                 return -ENOMEM;
 226
 227         for (idx = 0; idx < count; idx++) {
 228                 (*kctl)->vd[idx].access = access;
 229                 (*kctl)->vd[idx].owner = file;
 230         }
 231         (*kctl)->count = count;
 232
 233         return 0;
 234 }
 235
 236 /**
 237  * snd_ctl_new1 - create a control instance from the template
 238  * @ncontrol: the initialization record
 239  * @private_data: the private data to set
 240  *
 241  * Allocates a new struct snd_kcontrol instance and initialize from the given
 242  * template.  When the access field of ncontrol is 0, it's assumed as
 243  * READWRITE access. When the count field is 0, it's assumes as one.
 244  *
 245  * Return: The pointer of the newly generated instance, or %NULL on failure.
 246  */
 247 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 248                                   void *private_data)
 249 {
 250         struct snd_kcontrol *kctl;
 251         unsigned int count;
 252         unsigned int access;
 253         int err;
 254
 255         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 256                 return NULL;
 257
 258         count = ncontrol->count;
 259         if (count == 0)
 260                 count = 1;
 261
 262         access = ncontrol->access;
 263         if (access == 0)
 264                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 265         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 266                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 267                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 268                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 269                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 270                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
 271
 272         err = snd_ctl_new(&kctl, count, access, NULL);
 273         if (err < 0)
 274                 return NULL;
 275
 276         /* The 'numid' member is decided when calling snd_ctl_add(). */
 277         kctl->id.iface = ncontrol->iface;
 278         kctl->id.device = ncontrol->device;
 279         kctl->id.subdevice = ncontrol->subdevice;
 280         if (ncontrol->name) {
 281                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 282                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 283                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 284                                 ncontrol->name, kctl->id.name);
 285         }
 286         kctl->id.index = ncontrol->index;
 287
 288         kctl->info = ncontrol->info;
 289         kctl->get = ncontrol->get;
 290         kctl->put = ncontrol->put;
 291         kctl->tlv.p = ncontrol->tlv.p;
 292
 293         kctl->private_value = ncontrol->private_value;
 294         kctl->private_data = private_data;
 295
 296         return kctl;
 297 }
 298 EXPORT_SYMBOL(snd_ctl_new1);
 299
 300 /**
 301  * snd_ctl_free_one - release the control instance
 302  * @kcontrol: the control instance
 303  *
 304  * Releases the control instance created via snd_ctl_new()
 305  * or snd_ctl_new1().
 306  * Don't call this after the control was added to the card.
 307  */
 308 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 309 {
 310         if (kcontrol) {
 311                 if (kcontrol->private_free)
 312                         kcontrol->private_free(kcontrol);
 313                 kfree(kcontrol);
 314         }
 315 }
 316 EXPORT_SYMBOL(snd_ctl_free_one);
 317
 318 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 319                                           unsigned int count)
 320 {
 321         struct snd_kcontrol *kctl;
 322
 323         /* Make sure that the ids assigned to the control do not wrap around */
 324         if (card->last_numid >= UINT_MAX - count)
 325                 card->last_numid = 0;
 326
 327         list_for_each_entry(kctl, &card->controls, list) {
 328                 if (kctl->id.numid < card->last_numid + 1 + count &&
 329                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 330                         card->last_numid = kctl->id.numid + kctl->count - 1;
 331                         return true;
 332                 }
 333         }
 334         return false;
 335 }
 336
 337 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 338 {
 339         unsigned int iter = 100000;
 340
 341         while (snd_ctl_remove_numid_conflict(card, count)) {
 342                 if (--iter == 0) {
 343                         /* this situation is very unlikely */
 344                         dev_err(card->dev, "unable to allocate new control numid\n");
 345                         return -ENOMEM;
 346                 }
 347         }
 348         return 0;
 349 }
 350
 351 /* add a new kcontrol object; call with card->controls_rwsem locked */
 352 static int __snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 353 {
 354         struct snd_ctl_elem_id id;
 355         unsigned int idx;
 356         unsigned int count;
 357
 358         id = kcontrol->id;
 359         if (id.index > UINT_MAX - kcontrol->count)
 360                 return -EINVAL;
 361
 362         if (snd_ctl_find_id(card, &id)) {
 363                 dev_err(card->dev,
 364                         "control %i:%i:%i:%s:%i is already present\n",
 365                         id.iface, id.device, id.subdevice, id.name, id.index);
 366                 return -EBUSY;
 367         }
 368
 369         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 370                 return -ENOMEM;
 371
 372         list_add_tail(&kcontrol->list, &card->controls);
 373         card->controls_count += kcontrol->count;
 374         kcontrol->id.numid = card->last_numid + 1;
 375         card->last_numid += kcontrol->count;
 376
 377         id = kcontrol->id;
 378         count = kcontrol->count;
 379         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 380                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 381
 382         return 0;
 383 }
 384
 385 /**
 386  * snd_ctl_add - add the control instance to the card
 387  * @card: the card instance
 388  * @kcontrol: the control instance to add
 389  *
 390  * Adds the control instance created via snd_ctl_new() or
 391  * snd_ctl_new1() to the given card. Assigns also an unique
 392  * numid used for fast search.
 393  *
 394  * It frees automatically the control which cannot be added.
 395  *
 396  * Return: Zero if successful, or a negative error code on failure.
 397  *
 398  */
 399 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 400 {
 401         int err = -EINVAL;
 402
 403         if (! kcontrol)
 404                 return err;
 405         if (snd_BUG_ON(!card || !kcontrol->info))
 406                 goto error;
 407
 408         down_write(&card->controls_rwsem);
 409         err = __snd_ctl_add(card, kcontrol);
 410         up_write(&card->controls_rwsem);
 411         if (err < 0)
 412                 goto error;
 413         return 0;
 414
 415  error:
 416         snd_ctl_free_one(kcontrol);
 417         return err;
 418 }
 419 EXPORT_SYMBOL(snd_ctl_add);
 420
 421 /**
 422  * snd_ctl_replace - replace the control instance of the card
 423  * @card: the card instance
 424  * @kcontrol: the control instance to replace
 425  * @add_on_replace: add the control if not already added
 426  *
 427  * Replaces the given control.  If the given control does not exist
 428  * and the add_on_replace flag is set, the control is added.  If the
 429  * control exists, it is destroyed first.
 430  *
 431  * It frees automatically the control which cannot be added or replaced.
 432  *
 433  * Return: Zero if successful, or a negative error code on failure.
 434  */
 435 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 436                     bool add_on_replace)
 437 {
 438         struct snd_ctl_elem_id id;
 439         unsigned int count;
 440         unsigned int idx;
 441         struct snd_kcontrol *old;
 442         int ret;
 443
 444         if (!kcontrol)
 445                 return -EINVAL;
 446         if (snd_BUG_ON(!card || !kcontrol->info)) {
 447                 ret = -EINVAL;
 448                 goto error;
 449         }
 450         id = kcontrol->id;
 451         down_write(&card->controls_rwsem);
 452         old = snd_ctl_find_id(card, &id);
 453         if (!old) {
 454                 if (add_on_replace)
 455                         goto add;
 456                 up_write(&card->controls_rwsem);
 457                 ret = -EINVAL;
 458                 goto error;
 459         }
 460         ret = snd_ctl_remove(card, old);
 461         if (ret < 0) {
 462                 up_write(&card->controls_rwsem);
 463                 goto error;
 464         }
 465 add:
 466         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 467                 up_write(&card->controls_rwsem);
 468                 ret = -ENOMEM;
 469                 goto error;
 470         }
 471         list_add_tail(&kcontrol->list, &card->controls);
 472         card->controls_count += kcontrol->count;
 473         kcontrol->id.numid = card->last_numid + 1;
 474         card->last_numid += kcontrol->count;
 475         id = kcontrol->id;
 476         count = kcontrol->count;
 477         up_write(&card->controls_rwsem);
 478         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 479                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 480         return 0;
 481
 482 error:
 483         snd_ctl_free_one(kcontrol);
 484         return ret;
 485 }
 486 EXPORT_SYMBOL(snd_ctl_replace);
 487
 488 /**
 489  * snd_ctl_remove - remove the control from the card and release it
 490  * @card: the card instance
 491  * @kcontrol: the control instance to remove
 492  *
 493  * Removes the control from the card and then releases the instance.
 494  * You don't need to call snd_ctl_free_one(). You must be in
 495  * the write lock - down_write(&card->controls_rwsem).
 496  *
 497  * Return: 0 if successful, or a negative error code on failure.
 498  */
 499 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 500 {
 501         struct snd_ctl_elem_id id;
 502         unsigned int idx;
 503
 504         if (snd_BUG_ON(!card || !kcontrol))
 505                 return -EINVAL;
 506         list_del(&kcontrol->list);
 507         card->controls_count -= kcontrol->count;
 508         id = kcontrol->id;
 509         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 510                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 511         snd_ctl_free_one(kcontrol);
 512         return 0;
 513 }
 514 EXPORT_SYMBOL(snd_ctl_remove);
 515
 516 /**
 517  * snd_ctl_remove_id - remove the control of the given id and release it
 518  * @card: the card instance
 519  * @id: the control id to remove
 520  *
 521  * Finds the control instance with the given id, removes it from the
 522  * card list and releases it.
 523  *
 524  * Return: 0 if successful, or a negative error code on failure.
 525  */
 526 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 527 {
 528         struct snd_kcontrol *kctl;
 529         int ret;
 530
 531         down_write(&card->controls_rwsem);
 532         kctl = snd_ctl_find_id(card, id);
 533         if (kctl == NULL) {
 534                 up_write(&card->controls_rwsem);
 535                 return -ENOENT;
 536         }
 537         ret = snd_ctl_remove(card, kctl);
 538         up_write(&card->controls_rwsem);
 539         return ret;
 540 }
 541 EXPORT_SYMBOL(snd_ctl_remove_id);
 542
 543 /**
 544  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 545  * @file: active control handle
 546  * @id: the control id to remove
 547  *
 548  * Finds the control instance with the given id, removes it from the
 549  * card list and releases it.
 550  *
 551  * Return: 0 if successful, or a negative error code on failure.
 552  */
 553 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 554                                    struct snd_ctl_elem_id *id)
 555 {
 556         struct snd_card *card = file->card;
 557         struct snd_kcontrol *kctl;
 558         int idx, ret;
 559
 560         down_write(&card->controls_rwsem);
 561         kctl = snd_ctl_find_id(card, id);
 562         if (kctl == NULL) {
 563                 ret = -ENOENT;
 564                 goto error;
 565         }
 566         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 567                 ret = -EINVAL;
 568                 goto error;
 569         }
 570         for (idx = 0; idx < kctl->count; idx++)
 571                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 572                         ret = -EBUSY;
 573                         goto error;
 574                 }
 575         ret = snd_ctl_remove(card, kctl);
 576         if (ret < 0)
 577                 goto error;
 578         card->user_ctl_count--;
 579 error:
 580         up_write(&card->controls_rwsem);
 581         return ret;
 582 }
 583
 584 /**
 585  * snd_ctl_activate_id - activate/inactivate the control of the given id
 586  * @card: the card instance
 587  * @id: the control id to activate/inactivate
 588  * @active: non-zero to activate
 589  *
 590  * Finds the control instance with the given id, and activate or
 591  * inactivate the control together with notification, if changed.
 592  * The given ID data is filled with full information.
 593  *
 594  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 595  */
 596 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 597                         int active)
 598 {
 599         struct snd_kcontrol *kctl;
 600         struct snd_kcontrol_volatile *vd;
 601         unsigned int index_offset;
 602         int ret;
 603
 604         down_write(&card->controls_rwsem);
 605         kctl = snd_ctl_find_id(card, id);
 606         if (kctl == NULL) {
 607                 ret = -ENOENT;
 608                 goto unlock;
 609         }
 610         index_offset = snd_ctl_get_ioff(kctl, id);
 611         vd = &kctl->vd[index_offset];
 612         ret = 0;
 613         if (active) {
 614                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 615                         goto unlock;
 616                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 617         } else {
 618                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 619                         goto unlock;
 620                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 621         }
 622         snd_ctl_build_ioff(id, kctl, index_offset);
 623         ret = 1;
 624  unlock:
 625         up_write(&card->controls_rwsem);
 626         if (ret > 0)
 627                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 628         return ret;
 629 }
 630 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 631
 632 /**
 633  * snd_ctl_rename_id - replace the id of a control on the card
 634  * @card: the card instance
 635  * @src_id: the old id
 636  * @dst_id: the new id
 637  *
 638  * Finds the control with the old id from the card, and replaces the
 639  * id with the new one.
 640  *
 641  * Return: Zero if successful, or a negative error code on failure.
 642  */
 643 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 644                       struct snd_ctl_elem_id *dst_id)
 645 {
 646         struct snd_kcontrol *kctl;
 647
 648         down_write(&card->controls_rwsem);
 649         kctl = snd_ctl_find_id(card, src_id);
 650         if (kctl == NULL) {
 651                 up_write(&card->controls_rwsem);
 652                 return -ENOENT;
 653         }
 654         kctl->id = *dst_id;
 655         kctl->id.numid = card->last_numid + 1;
 656         card->last_numid += kctl->count;
 657         up_write(&card->controls_rwsem);
 658         return 0;
 659 }
 660 EXPORT_SYMBOL(snd_ctl_rename_id);
 661
 662 /**
 663  * snd_ctl_find_numid - find the control instance with the given number-id
 664  * @card: the card instance
 665  * @numid: the number-id to search
 666  *
 667  * Finds the control instance with the given number-id from the card.
 668  *
 669  * The caller must down card->controls_rwsem before calling this function
 670  * (if the race condition can happen).
 671  *
 672  * Return: The pointer of the instance if found, or %NULL if not.
 673  *
 674  */
 675 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 676 {
 677         struct snd_kcontrol *kctl;
 678
 679         if (snd_BUG_ON(!card || !numid))
 680                 return NULL;
 681         list_for_each_entry(kctl, &card->controls, list) {
 682                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 683                         return kctl;
 684         }
 685         return NULL;
 686 }
 687 EXPORT_SYMBOL(snd_ctl_find_numid);
 688
 689 /**
 690  * snd_ctl_find_id - find the control instance with the given id
 691  * @card: the card instance
 692  * @id: the id to search
 693  *
 694  * Finds the control instance with the given id from the card.
 695  *
 696  * The caller must down card->controls_rwsem before calling this function
 697  * (if the race condition can happen).
 698  *
 699  * Return: The pointer of the instance if found, or %NULL if not.
 700  *
 701  */
 702 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 703                                      struct snd_ctl_elem_id *id)
 704 {
 705         struct snd_kcontrol *kctl;
 706
 707         if (snd_BUG_ON(!card || !id))
 708                 return NULL;
 709         if (id->numid != 0)
 710                 return snd_ctl_find_numid(card, id->numid);
 711         list_for_each_entry(kctl, &card->controls, list) {
 712                 if (kctl->id.iface != id->iface)
 713                         continue;
 714                 if (kctl->id.device != id->device)
 715                         continue;
 716                 if (kctl->id.subdevice != id->subdevice)
 717                         continue;
 718                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 719                         continue;
 720                 if (kctl->id.index > id->index)
 721                         continue;
 722                 if (kctl->id.index + kctl->count <= id->index)
 723                         continue;
 724                 return kctl;
 725         }
 726         return NULL;
 727 }
 728 EXPORT_SYMBOL(snd_ctl_find_id);
 729
 730 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 731                              unsigned int cmd, void __user *arg)
 732 {
 733         struct snd_ctl_card_info *info;
 734
 735         info = kzalloc(sizeof(*info), GFP_KERNEL);
 736         if (! info)
 737                 return -ENOMEM;
 738         down_read(&snd_ioctl_rwsem);
 739         info->card = card->number;
 740         strlcpy(info->id, card->id, sizeof(info->id));
 741         strlcpy(info->driver, card->driver, sizeof(info->driver));
 742         strlcpy(info->name, card->shortname, sizeof(info->name));
 743         strlcpy(info->longname, card->longname, sizeof(info->longname));
 744         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 745         strlcpy(info->components, card->components, sizeof(info->components));
 746         up_read(&snd_ioctl_rwsem);
 747         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 748                 kfree(info);
 749                 return -EFAULT;
 750         }
 751         kfree(info);
 752         return 0;
 753 }
 754
 755 static int snd_ctl_elem_list(struct snd_card *card,
 756                              struct snd_ctl_elem_list __user *_list)
 757 {
 758         struct snd_ctl_elem_list list;
 759         struct snd_kcontrol *kctl;
 760         struct snd_ctl_elem_id id;
 761         unsigned int offset, space, jidx;
 762         int err = 0;
 763
 764         if (copy_from_user(&list, _list, sizeof(list)))
 765                 return -EFAULT;
 766         offset = list.offset;
 767         space = list.space;
 768
 769         down_read(&card->controls_rwsem);
 770         list.count = card->controls_count;
 771         list.used = 0;
 772         if (space > 0) {
 773                 list_for_each_entry(kctl, &card->controls, list) {
 774                         if (offset >= kctl->count) {
 775                                 offset -= kctl->count;
 776                                 continue;
 777                         }
 778                         for (jidx = offset; jidx < kctl->count; jidx++) {
 779                                 snd_ctl_build_ioff(&id, kctl, jidx);
 780                                 if (copy_to_user(list.pids + list.used, &id,
 781                                                  sizeof(id))) {
 782                                         err = -EFAULT;
 783                                         goto out;
 784                                 }
 785                                 list.used++;
 786                                 if (!--space)
 787                                         goto out;
 788                         }
 789                         offset = 0;
 790                 }
 791         }
 792  out:
 793         up_read(&card->controls_rwsem);
 794         if (!err && copy_to_user(_list, &list, sizeof(list)))
 795                 err = -EFAULT;
 796         return err;
 797 }
 798
 799 static bool validate_element_member_dimension(struct snd_ctl_elem_info *info)
 800 {
 801         unsigned int members;
 802         unsigned int i;
 803
 804         if (info->dimen.d[0] == 0)
 805                 return true;
 806
 807         members = 1;
 808         for (i = 0; i < ARRAY_SIZE(info->dimen.d); ++i) {
 809                 if (info->dimen.d[i] == 0)
 810                         break;
 811                 members *= info->dimen.d[i];
 812
 813                 /*
 814                  * info->count should be validated in advance, to guarantee
 815                  * calculation soundness.
 816                  */
 817                 if (members > info->count)
 818                         return false;
 819         }
 820
 821         for (++i; i < ARRAY_SIZE(info->dimen.d); ++i) {
 822                 if (info->dimen.d[i] > 0)
 823                         return false;
 824         }
 825
 826         return members == info->count;
 827 }
 828
 829 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 830                              struct snd_ctl_elem_info *info)
 831 {
 832         struct snd_card *card = ctl->card;
 833         struct snd_kcontrol *kctl;
 834         struct snd_kcontrol_volatile *vd;
 835         unsigned int index_offset;
 836         int result;
 837
 838         down_read(&card->controls_rwsem);
 839         kctl = snd_ctl_find_id(card, &info->id);
 840         if (kctl == NULL) {
 841                 up_read(&card->controls_rwsem);
 842                 return -ENOENT;
 843         }
 844 #ifdef CONFIG_SND_DEBUG
 845         info->access = 0;
 846 #endif
 847         result = kctl->info(kctl, info);
 848         if (result >= 0) {
 849                 snd_BUG_ON(info->access);
 850                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 851                 vd = &kctl->vd[index_offset];
 852                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 853                 info->access = vd->access;
 854                 if (vd->owner) {
 855                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 856                         if (vd->owner == ctl)
 857                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 858                         info->owner = pid_vnr(vd->owner->pid);
 859                 } else {
 860                         info->owner = -1;
 861                 }
 862         }
 863         up_read(&card->controls_rwsem);
 864         return result;
 865 }
 866
 867 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 868                                   struct snd_ctl_elem_info __user *_info)
 869 {
 870         struct snd_ctl_elem_info info;
 871         int result;
 872
 873         if (copy_from_user(&info, _info, sizeof(info)))
 874                 return -EFAULT;
 875         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 876         if (result < 0)
 877                 return result;
 878         result = snd_ctl_elem_info(ctl, &info);
 879         if (result < 0)
 880                 return result;
 881         if (copy_to_user(_info, &info, sizeof(info)))
 882                 return -EFAULT;
 883         return result;
 884 }
 885
 886 static int snd_ctl_elem_read(struct snd_card *card,
 887                              struct snd_ctl_elem_value *control)
 888 {
 889         struct snd_kcontrol *kctl;
 890         struct snd_kcontrol_volatile *vd;
 891         unsigned int index_offset;
 892
 893         kctl = snd_ctl_find_id(card, &control->id);
 894         if (kctl == NULL)
 895                 return -ENOENT;
 896
 897         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 898         vd = &kctl->vd[index_offset];
 899         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
 900                 return -EPERM;
 901
 902         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 903         return kctl->get(kctl, control);
 904 }
 905
 906 static int snd_ctl_elem_read_user(struct snd_card *card,
 907                                   struct snd_ctl_elem_value __user *_control)
 908 {
 909         struct snd_ctl_elem_value *control;
 910         int result;
 911
 912         control = memdup_user(_control, sizeof(*control));
 913         if (IS_ERR(control))
 914                 return PTR_ERR(control);
 915
 916         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 917         if (result < 0)
 918                 goto error;
 919
 920         down_read(&card->controls_rwsem);
 921         result = snd_ctl_elem_read(card, control);
 922         up_read(&card->controls_rwsem);
 923         if (result < 0)
 924                 goto error;
 925
 926         if (copy_to_user(_control, control, sizeof(*control)))
 927                 result = -EFAULT;
 928  error:
 929         kfree(control);
 930         return result;
 931 }
 932
 933 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 934                               struct snd_ctl_elem_value *control)
 935 {
 936         struct snd_kcontrol *kctl;
 937         struct snd_kcontrol_volatile *vd;
 938         unsigned int index_offset;
 939         int result;
 940
 941         kctl = snd_ctl_find_id(card, &control->id);
 942         if (kctl == NULL)
 943                 return -ENOENT;
 944
 945         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 946         vd = &kctl->vd[index_offset];
 947         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
 948             (file && vd->owner && vd->owner != file)) {
 949                 return -EPERM;
 950         }
 951
 952         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 953         result = kctl->put(kctl, control);
 954         if (result < 0)
 955                 return result;
 956
 957         if (result > 0) {
 958                 struct snd_ctl_elem_id id = control->id;
 959                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 960         }
 961
 962         return 0;
 963 }
 964
 965 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 966                                    struct snd_ctl_elem_value __user *_control)
 967 {
 968         struct snd_ctl_elem_value *control;
 969         struct snd_card *card;
 970         int result;
 971
 972         control = memdup_user(_control, sizeof(*control));
 973         if (IS_ERR(control))
 974                 return PTR_ERR(control);
 975
 976         card = file->card;
 977         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 978         if (result < 0)
 979                 goto error;
 980
 981         down_write(&card->controls_rwsem);
 982         result = snd_ctl_elem_write(card, file, control);
 983         up_write(&card->controls_rwsem);
 984         if (result < 0)
 985                 goto error;
 986
 987         if (copy_to_user(_control, control, sizeof(*control)))
 988                 result = -EFAULT;
 989  error:
 990         kfree(control);
 991         return result;
 992 }
 993
 994 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 995                              struct snd_ctl_elem_id __user *_id)
 996 {
 997         struct snd_card *card = file->card;
 998         struct snd_ctl_elem_id id;
 999         struct snd_kcontrol *kctl;
1000         struct snd_kcontrol_volatile *vd;
1001         int result;
1002
1003         if (copy_from_user(&id, _id, sizeof(id)))
1004                 return -EFAULT;
1005         down_write(&card->controls_rwsem);
1006         kctl = snd_ctl_find_id(card, &id);
1007         if (kctl == NULL) {
1008                 result = -ENOENT;
1009         } else {
1010                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1011                 if (vd->owner != NULL)
1012                         result = -EBUSY;
1013                 else {
1014                         vd->owner = file;
1015                         result = 0;
1016                 }
1017         }
1018         up_write(&card->controls_rwsem);
1019         return result;
1020 }
1021
1022 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1023                                struct snd_ctl_elem_id __user *_id)
1024 {
1025         struct snd_card *card = file->card;
1026         struct snd_ctl_elem_id id;
1027         struct snd_kcontrol *kctl;
1028         struct snd_kcontrol_volatile *vd;
1029         int result;
1030
1031         if (copy_from_user(&id, _id, sizeof(id)))
1032                 return -EFAULT;
1033         down_write(&card->controls_rwsem);
1034         kctl = snd_ctl_find_id(card, &id);
1035         if (kctl == NULL) {
1036                 result = -ENOENT;
1037         } else {
1038                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1039                 if (vd->owner == NULL)
1040                         result = -EINVAL;
1041                 else if (vd->owner != file)
1042                         result = -EPERM;
1043                 else {
1044                         vd->owner = NULL;
1045                         result = 0;
1046                 }
1047         }
1048         up_write(&card->controls_rwsem);
1049         return result;
1050 }
1051
1052 struct user_element {
1053         struct snd_ctl_elem_info info;
1054         struct snd_card *card;
1055         char *elem_data;                /* element data */
1056         unsigned long elem_data_size;   /* size of element data in bytes */
1057         void *tlv_data;                 /* TLV data */
1058         unsigned long tlv_data_size;    /* TLV data size */
1059         void *priv_data;                /* private data (like strings for enumerated type) */
1060 };
1061
1062 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1063                                   struct snd_ctl_elem_info *uinfo)
1064 {
1065         struct user_element *ue = kcontrol->private_data;
1066         unsigned int offset;
1067
1068         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1069         *uinfo = ue->info;
1070         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1071
1072         return 0;
1073 }
1074
1075 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1076                                        struct snd_ctl_elem_info *uinfo)
1077 {
1078         struct user_element *ue = kcontrol->private_data;
1079         const char *names;
1080         unsigned int item;
1081         unsigned int offset;
1082
1083         item = uinfo->value.enumerated.item;
1084
1085         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1086         *uinfo = ue->info;
1087         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1088
1089         item = min(item, uinfo->value.enumerated.items - 1);
1090         uinfo->value.enumerated.item = item;
1091
1092         names = ue->priv_data;
1093         for (; item > 0; --item)
1094                 names += strlen(names) + 1;
1095         strcpy(uinfo->value.enumerated.name, names);
1096
1097         return 0;
1098 }
1099
1100 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1101                                  struct snd_ctl_elem_value *ucontrol)
1102 {
1103         struct user_element *ue = kcontrol->private_data;
1104         unsigned int size = ue->elem_data_size;
1105         char *src = ue->elem_data +
1106                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1107
1108         memcpy(&ucontrol->value, src, size);
1109         return 0;
1110 }
1111
1112 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1113                                  struct snd_ctl_elem_value *ucontrol)
1114 {
1115         int change;
1116         struct user_element *ue = kcontrol->private_data;
1117         unsigned int size = ue->elem_data_size;
1118         char *dst = ue->elem_data +
1119                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1120
1121         change = memcmp(&ucontrol->value, dst, size) != 0;
1122         if (change)
1123                 memcpy(dst, &ucontrol->value, size);
1124         return change;
1125 }
1126
1127 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1128                             unsigned int size)
1129 {
1130         struct user_element *ue = kctl->private_data;
1131         unsigned int *container;
1132         struct snd_ctl_elem_id id;
1133         unsigned int mask = 0;
1134         int i;
1135         int change;
1136
1137         if (size > 1024 * 128)  /* sane value */
1138                 return -EINVAL;
1139
1140         container = vmemdup_user(buf, size);
1141         if (IS_ERR(container))
1142                 return PTR_ERR(container);
1143
1144         change = ue->tlv_data_size != size;
1145         if (!change)
1146                 change = memcmp(ue->tlv_data, container, size) != 0;
1147         if (!change) {
1148                 kvfree(container);
1149                 return 0;
1150         }
1151
1152         if (ue->tlv_data == NULL) {
1153                 /* Now TLV data is available. */
1154                 for (i = 0; i < kctl->count; ++i)
1155                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1156                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1157         }
1158
1159         kvfree(ue->tlv_data);
1160         ue->tlv_data = container;
1161         ue->tlv_data_size = size;
1162
1163         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1164         for (i = 0; i < kctl->count; ++i) {
1165                 snd_ctl_build_ioff(&id, kctl, i);
1166                 snd_ctl_notify(ue->card, mask, &id);
1167         }
1168
1169         return change;
1170 }
1171
1172 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1173                          unsigned int size)
1174 {
1175         struct user_element *ue = kctl->private_data;
1176
1177         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1178                 return -ENXIO;
1179
1180         if (size < ue->tlv_data_size)
1181                 return -ENOSPC;
1182
1183         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1184                 return -EFAULT;
1185
1186         return 0;
1187 }
1188
1189 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1190                                  unsigned int size, unsigned int __user *buf)
1191 {
1192         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1193                 return replace_user_tlv(kctl, buf, size);
1194         else
1195                 return read_user_tlv(kctl, buf, size);
1196 }
1197
1198 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1199 {
1200         char *names, *p;
1201         size_t buf_len, name_len;
1202         unsigned int i;
1203         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1204
1205         if (ue->info.value.enumerated.names_length > 64 * 1024)
1206                 return -EINVAL;
1207
1208         names = vmemdup_user((const void __user *)user_ptrval,
1209                 ue->info.value.enumerated.names_length);
1210         if (IS_ERR(names))
1211                 return PTR_ERR(names);
1212
1213         /* check that there are enough valid names */
1214         buf_len = ue->info.value.enumerated.names_length;
1215         p = names;
1216         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1217                 name_len = strnlen(p, buf_len);
1218                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1219                         kvfree(names);
1220                         return -EINVAL;
1221                 }
1222                 p += name_len + 1;
1223                 buf_len -= name_len + 1;
1224         }
1225
1226         ue->priv_data = names;
1227         ue->info.value.enumerated.names_ptr = 0;
1228
1229         return 0;
1230 }
1231
1232 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1233 {
1234         struct user_element *ue = kcontrol->private_data;
1235
1236         kvfree(ue->tlv_data);
1237         kvfree(ue->priv_data);
1238         kfree(ue);
1239 }
1240
1241 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1242                             struct snd_ctl_elem_info *info, int replace)
1243 {
1244         /* The capacity of struct snd_ctl_elem_value.value.*/
1245         static const unsigned int value_sizes[] = {
1246                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
1247                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
1248                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1249                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
1250                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
1251                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1252         };
1253         static const unsigned int max_value_counts[] = {
1254                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
1255                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
1256                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1257                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
1258                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
1259                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1260         };
1261         struct snd_card *card = file->card;
1262         struct snd_kcontrol *kctl;
1263         unsigned int count;
1264         unsigned int access;
1265         long private_size;
1266         struct user_element *ue;
1267         unsigned int offset;
1268         int err;
1269
1270         if (!*info->id.name)
1271                 return -EINVAL;
1272         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1273                 return -EINVAL;
1274
1275         /* Delete a control to replace them if needed. */
1276         if (replace) {
1277                 info->id.numid = 0;
1278                 err = snd_ctl_remove_user_ctl(file, &info->id);
1279                 if (err)
1280                         return err;
1281         }
1282
1283         /*
1284          * The number of userspace controls are counted control by control,
1285          * not element by element.
1286          */
1287         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1288                 return -ENOMEM;
1289
1290         /* Check the number of elements for this userspace control. */
1291         count = info->owner;
1292         if (count == 0)
1293                 count = 1;
1294
1295         /* Arrange access permissions if needed. */
1296         access = info->access;
1297         if (access == 0)
1298                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1299         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1300                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1301                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1302
1303         /* In initial state, nothing is available as TLV container. */
1304         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1305                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1306         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1307
1308         /*
1309          * Check information and calculate the size of data specific to
1310          * this userspace control.
1311          */
1312         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1313             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1314                 return -EINVAL;
1315         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1316             info->value.enumerated.items == 0)
1317                 return -EINVAL;
1318         if (info->count < 1 ||
1319             info->count > max_value_counts[info->type])
1320                 return -EINVAL;
1321         if (!validate_element_member_dimension(info))
1322                 return -EINVAL;
1323         private_size = value_sizes[info->type] * info->count;
1324
1325         /*
1326          * Keep memory object for this userspace control. After passing this
1327          * code block, the instance should be freed by snd_ctl_free_one().
1328          *
1329          * Note that these elements in this control are locked.
1330          */
1331         err = snd_ctl_new(&kctl, count, access, file);
1332         if (err < 0)
1333                 return err;
1334         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1335         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1336                                      GFP_KERNEL);
1337         if (kctl->private_data == NULL) {
1338                 kfree(kctl);
1339                 return -ENOMEM;
1340         }
1341         kctl->private_free = snd_ctl_elem_user_free;
1342
1343         /* Set private data for this userspace control. */
1344         ue = (struct user_element *)kctl->private_data;
1345         ue->card = card;
1346         ue->info = *info;
1347         ue->info.access = 0;
1348         ue->elem_data = (char *)ue + sizeof(*ue);
1349         ue->elem_data_size = private_size;
1350         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1351                 err = snd_ctl_elem_init_enum_names(ue);
1352                 if (err < 0) {
1353                         snd_ctl_free_one(kctl);
1354                         return err;
1355                 }
1356         }
1357
1358         /* Set callback functions. */
1359         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1360                 kctl->info = snd_ctl_elem_user_enum_info;
1361         else
1362                 kctl->info = snd_ctl_elem_user_info;
1363         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1364                 kctl->get = snd_ctl_elem_user_get;
1365         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1366                 kctl->put = snd_ctl_elem_user_put;
1367         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1368                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1369
1370         /* This function manage to free the instance on failure. */
1371         down_write(&card->controls_rwsem);
1372         err = __snd_ctl_add(card, kctl);
1373         if (err < 0) {
1374                 snd_ctl_free_one(kctl);
1375                 goto unlock;
1376         }
1377         offset = snd_ctl_get_ioff(kctl, &info->id);
1378         snd_ctl_build_ioff(&info->id, kctl, offset);
1379         /*
1380          * Here we cannot fill any field for the number of elements added by
1381          * this operation because there're no specific fields. The usage of
1382          * 'owner' field for this purpose may cause any bugs to userspace
1383          * applications because the field originally means PID of a process
1384          * which locks the element.
1385          */
1386
1387         card->user_ctl_count++;
1388
1389  unlock:
1390         up_write(&card->controls_rwsem);
1391         return 0;
1392 }
1393
1394 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1395                                  struct snd_ctl_elem_info __user *_info, int replace)
1396 {
1397         struct snd_ctl_elem_info info;
1398         int err;
1399
1400         if (copy_from_user(&info, _info, sizeof(info)))
1401                 return -EFAULT;
1402         err = snd_ctl_elem_add(file, &info, replace);
1403         if (err < 0)
1404                 return err;
1405         if (copy_to_user(_info, &info, sizeof(info))) {
1406                 snd_ctl_remove_user_ctl(file, &info.id);
1407                 return -EFAULT;
1408         }
1409
1410         return 0;
1411 }
1412
1413 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1414                                struct snd_ctl_elem_id __user *_id)
1415 {
1416         struct snd_ctl_elem_id id;
1417
1418         if (copy_from_user(&id, _id, sizeof(id)))
1419                 return -EFAULT;
1420         return snd_ctl_remove_user_ctl(file, &id);
1421 }
1422
1423 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1424 {
1425         int subscribe;
1426         if (get_user(subscribe, ptr))
1427                 return -EFAULT;
1428         if (subscribe < 0) {
1429                 subscribe = file->subscribed;
1430                 if (put_user(subscribe, ptr))
1431                         return -EFAULT;
1432                 return 0;
1433         }
1434         if (subscribe) {
1435                 file->subscribed = 1;
1436                 return 0;
1437         } else if (file->subscribed) {
1438                 snd_ctl_empty_read_queue(file);
1439                 file->subscribed = 0;
1440         }
1441         return 0;
1442 }
1443
1444 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1445                             struct snd_kcontrol *kctl,
1446                             struct snd_ctl_elem_id *id,
1447                             unsigned int __user *buf, unsigned int size)
1448 {
1449         static const struct {
1450                 int op;
1451                 int perm;
1452         } pairs[] = {
1453                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1454                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1455                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1456         };
1457         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1458         int i;
1459
1460         /* Check support of the request for this element. */
1461         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1462                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1463                         break;
1464         }
1465         if (i == ARRAY_SIZE(pairs))
1466                 return -ENXIO;
1467
1468         if (kctl->tlv.c == NULL)
1469                 return -ENXIO;
1470
1471         /* When locked, this is unavailable. */
1472         if (vd->owner != NULL && vd->owner != file)
1473                 return -EPERM;
1474
1475         return kctl->tlv.c(kctl, op_flag, size, buf);
1476 }
1477
1478 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1479                         unsigned int __user *buf, unsigned int size)
1480 {
1481         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1482         unsigned int len;
1483
1484         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1485                 return -ENXIO;
1486
1487         if (kctl->tlv.p == NULL)
1488                 return -ENXIO;
1489
1490         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1491         if (size < len)
1492                 return -ENOMEM;
1493
1494         if (copy_to_user(buf, kctl->tlv.p, len))
1495                 return -EFAULT;
1496
1497         return 0;
1498 }
1499
1500 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1501                              struct snd_ctl_tlv __user *buf,
1502                              int op_flag)
1503 {
1504         struct snd_ctl_tlv header;
1505         unsigned int __user *container;
1506         unsigned int container_size;
1507         struct snd_kcontrol *kctl;
1508         struct snd_ctl_elem_id id;
1509         struct snd_kcontrol_volatile *vd;
1510
1511         if (copy_from_user(&header, buf, sizeof(header)))
1512                 return -EFAULT;
1513
1514         /* In design of control core, numerical ID starts at 1. */
1515         if (header.numid == 0)
1516                 return -EINVAL;
1517
1518         /* At least, container should include type and length fields.  */
1519         if (header.length < sizeof(unsigned int) * 2)
1520                 return -EINVAL;
1521         container_size = header.length;
1522         container = buf->tlv;
1523
1524         kctl = snd_ctl_find_numid(file->card, header.numid);
1525         if (kctl == NULL)
1526                 return -ENOENT;
1527
1528         /* Calculate index of the element in this set. */
1529         id = kctl->id;
1530         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1531         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1532
1533         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1534                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1535                                         container_size);
1536         } else {
1537                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1538                         return read_tlv_buf(kctl, &id, container,
1539                                             container_size);
1540                 }
1541         }
1542
1543         /* Not supported. */
1544         return -ENXIO;
1545 }
1546
1547 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1548 {
1549         struct snd_ctl_file *ctl;
1550         struct snd_card *card;
1551         struct snd_kctl_ioctl *p;
1552         void __user *argp = (void __user *)arg;
1553         int __user *ip = argp;
1554         int err;
1555
1556         ctl = file->private_data;
1557         card = ctl->card;
1558         if (snd_BUG_ON(!card))
1559                 return -ENXIO;
1560         switch (cmd) {
1561         case SNDRV_CTL_IOCTL_PVERSION:
1562                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1563         case SNDRV_CTL_IOCTL_CARD_INFO:
1564                 return snd_ctl_card_info(card, ctl, cmd, argp);
1565         case SNDRV_CTL_IOCTL_ELEM_LIST:
1566                 return snd_ctl_elem_list(card, argp);
1567         case SNDRV_CTL_IOCTL_ELEM_INFO:
1568                 return snd_ctl_elem_info_user(ctl, argp);
1569         case SNDRV_CTL_IOCTL_ELEM_READ:
1570                 return snd_ctl_elem_read_user(card, argp);
1571         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1572                 return snd_ctl_elem_write_user(ctl, argp);
1573         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1574                 return snd_ctl_elem_lock(ctl, argp);
1575         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1576                 return snd_ctl_elem_unlock(ctl, argp);
1577         case SNDRV_CTL_IOCTL_ELEM_ADD:
1578                 return snd_ctl_elem_add_user(ctl, argp, 0);
1579         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1580                 return snd_ctl_elem_add_user(ctl, argp, 1);
1581         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1582                 return snd_ctl_elem_remove(ctl, argp);
1583         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1584                 return snd_ctl_subscribe_events(ctl, ip);
1585         case SNDRV_CTL_IOCTL_TLV_READ:
1586                 down_read(&ctl->card->controls_rwsem);
1587                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1588                 up_read(&ctl->card->controls_rwsem);
1589                 return err;
1590         case SNDRV_CTL_IOCTL_TLV_WRITE:
1591                 down_write(&ctl->card->controls_rwsem);
1592                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1593                 up_write(&ctl->card->controls_rwsem);
1594                 return err;
1595         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1596                 down_write(&ctl->card->controls_rwsem);
1597                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1598                 up_write(&ctl->card->controls_rwsem);
1599                 return err;
1600         case SNDRV_CTL_IOCTL_POWER:
1601                 return -ENOPROTOOPT;
1602         case SNDRV_CTL_IOCTL_POWER_STATE:
1603 #ifdef CONFIG_PM
1604                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1605 #else
1606                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1607 #endif
1608         }
1609         down_read(&snd_ioctl_rwsem);
1610         list_for_each_entry(p, &snd_control_ioctls, list) {
1611                 err = p->fioctl(card, ctl, cmd, arg);
1612                 if (err != -ENOIOCTLCMD) {
1613                         up_read(&snd_ioctl_rwsem);
1614                         return err;
1615                 }
1616         }
1617         up_read(&snd_ioctl_rwsem);
1618         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1619         return -ENOTTY;
1620 }
1621
1622 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1623                             size_t count, loff_t * offset)
1624 {
1625         struct snd_ctl_file *ctl;
1626         int err = 0;
1627         ssize_t result = 0;
1628
1629         ctl = file->private_data;
1630         if (snd_BUG_ON(!ctl || !ctl->card))
1631                 return -ENXIO;
1632         if (!ctl->subscribed)
1633                 return -EBADFD;
1634         if (count < sizeof(struct snd_ctl_event))
1635                 return -EINVAL;
1636         spin_lock_irq(&ctl->read_lock);
1637         while (count >= sizeof(struct snd_ctl_event)) {
1638                 struct snd_ctl_event ev;
1639                 struct snd_kctl_event *kev;
1640                 while (list_empty(&ctl->events)) {
1641                         wait_queue_entry_t wait;
1642                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1643                                 err = -EAGAIN;
1644                                 goto __end_lock;
1645                         }
1646                         init_waitqueue_entry(&wait, current);
1647                         add_wait_queue(&ctl->change_sleep, &wait);
1648                         set_current_state(TASK_INTERRUPTIBLE);
1649                         spin_unlock_irq(&ctl->read_lock);
1650                         schedule();
1651                         remove_wait_queue(&ctl->change_sleep, &wait);
1652                         if (ctl->card->shutdown)
1653                                 return -ENODEV;
1654                         if (signal_pending(current))
1655                                 return -ERESTARTSYS;
1656                         spin_lock_irq(&ctl->read_lock);
1657                 }
1658                 kev = snd_kctl_event(ctl->events.next);
1659                 ev.type = SNDRV_CTL_EVENT_ELEM;
1660                 ev.data.elem.mask = kev->mask;
1661                 ev.data.elem.id = kev->id;
1662                 list_del(&kev->list);
1663                 spin_unlock_irq(&ctl->read_lock);
1664                 kfree(kev);
1665                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1666                         err = -EFAULT;
1667                         goto __end;
1668                 }
1669                 spin_lock_irq(&ctl->read_lock);
1670                 buffer += sizeof(struct snd_ctl_event);
1671                 count -= sizeof(struct snd_ctl_event);
1672                 result += sizeof(struct snd_ctl_event);
1673         }
1674       __end_lock:
1675         spin_unlock_irq(&ctl->read_lock);
1676       __end:
1677         return result > 0 ? result : err;
1678 }
1679
1680 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1681 {
1682         __poll_t mask;
1683         struct snd_ctl_file *ctl;
1684
1685         ctl = file->private_data;
1686         if (!ctl->subscribed)
1687                 return 0;
1688         poll_wait(file, &ctl->change_sleep, wait);
1689
1690         mask = 0;
1691         if (!list_empty(&ctl->events))
1692                 mask |= EPOLLIN | EPOLLRDNORM;
1693
1694         return mask;
1695 }
1696
1697 /*
1698  * register the device-specific control-ioctls.
1699  * called from each device manager like pcm.c, hwdep.c, etc.
1700  */
1701 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1702 {
1703         struct snd_kctl_ioctl *pn;
1704
1705         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1706         if (pn == NULL)
1707                 return -ENOMEM;
1708         pn->fioctl = fcn;
1709         down_write(&snd_ioctl_rwsem);
1710         list_add_tail(&pn->list, lists);
1711         up_write(&snd_ioctl_rwsem);
1712         return 0;
1713 }
1714
1715 /**
1716  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1717  * @fcn: ioctl callback function
1718  *
1719  * called from each device manager like pcm.c, hwdep.c, etc.
1720  */
1721 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1722 {
1723         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1724 }
1725 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1726
1727 #ifdef CONFIG_COMPAT
1728 /**
1729  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1730  * control-ioctls
1731  * @fcn: ioctl callback function
1732  */
1733 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1734 {
1735         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1736 }
1737 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1738 #endif
1739
1740 /*
1741  * de-register the device-specific control-ioctls.
1742  */
1743 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1744                                      struct list_head *lists)
1745 {
1746         struct snd_kctl_ioctl *p;
1747
1748         if (snd_BUG_ON(!fcn))
1749                 return -EINVAL;
1750         down_write(&snd_ioctl_rwsem);
1751         list_for_each_entry(p, lists, list) {
1752                 if (p->fioctl == fcn) {
1753                         list_del(&p->list);
1754                         up_write(&snd_ioctl_rwsem);
1755                         kfree(p);
1756                         return 0;
1757                 }
1758         }
1759         up_write(&snd_ioctl_rwsem);
1760         snd_BUG();
1761         return -EINVAL;
1762 }
1763
1764 /**
1765  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1766  * @fcn: ioctl callback function to unregister
1767  */
1768 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1769 {
1770         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1771 }
1772 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1773
1774 #ifdef CONFIG_COMPAT
1775 /**
1776  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1777  * control-ioctls
1778  * @fcn: ioctl callback function to unregister
1779  */
1780 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1781 {
1782         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1783 }
1784 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1785 #endif
1786
1787 static int snd_ctl_fasync(int fd, struct file * file, int on)
1788 {
1789         struct snd_ctl_file *ctl;
1790
1791         ctl = file->private_data;
1792         return fasync_helper(fd, file, on, &ctl->fasync);
1793 }
1794
1795 /* return the preferred subdevice number if already assigned;
1796  * otherwise return -1
1797  */
1798 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1799 {
1800         struct snd_ctl_file *kctl;
1801         int subdevice = -1;
1802
1803         read_lock(&card->ctl_files_rwlock);
1804         list_for_each_entry(kctl, &card->ctl_files, list) {
1805                 if (kctl->pid == task_pid(current)) {
1806                         subdevice = kctl->preferred_subdevice[type];
1807                         if (subdevice != -1)
1808                                 break;
1809                 }
1810         }
1811         read_unlock(&card->ctl_files_rwlock);
1812         return subdevice;
1813 }
1814 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1815
1816 /*
1817  * ioctl32 compat
1818  */
1819 #ifdef CONFIG_COMPAT
1820 #include "control_compat.c"
1821 #else
1822 #define snd_ctl_ioctl_compat    NULL
1823 #endif
1824
1825 /*
1826  *  INIT PART
1827  */
1828
1829 static const struct file_operations snd_ctl_f_ops =
1830 {
1831         .owner =        THIS_MODULE,
1832         .read =         snd_ctl_read,
1833         .open =         snd_ctl_open,
1834         .release =      snd_ctl_release,
1835         .llseek =       no_llseek,
1836         .poll =         snd_ctl_poll,
1837         .unlocked_ioctl =       snd_ctl_ioctl,
1838         .compat_ioctl = snd_ctl_ioctl_compat,
1839         .fasync =       snd_ctl_fasync,
1840 };
1841
1842 /*
1843  * registration of the control device
1844  */
1845 static int snd_ctl_dev_register(struct snd_device *device)
1846 {
1847         struct snd_card *card = device->device_data;
1848
1849         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1850                                    &snd_ctl_f_ops, card, &card->ctl_dev);
1851 }
1852
1853 /*
1854  * disconnection of the control device
1855  */
1856 static int snd_ctl_dev_disconnect(struct snd_device *device)
1857 {
1858         struct snd_card *card = device->device_data;
1859         struct snd_ctl_file *ctl;
1860
1861         read_lock(&card->ctl_files_rwlock);
1862         list_for_each_entry(ctl, &card->ctl_files, list) {
1863                 wake_up(&ctl->change_sleep);
1864                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1865         }
1866         read_unlock(&card->ctl_files_rwlock);
1867
1868         return snd_unregister_device(&card->ctl_dev);
1869 }
1870
1871 /*
1872  * free all controls
1873  */
1874 static int snd_ctl_dev_free(struct snd_device *device)
1875 {
1876         struct snd_card *card = device->device_data;
1877         struct snd_kcontrol *control;
1878
1879         down_write(&card->controls_rwsem);
1880         while (!list_empty(&card->controls)) {
1881                 control = snd_kcontrol(card->controls.next);
1882                 snd_ctl_remove(card, control);
1883         }
1884         up_write(&card->controls_rwsem);
1885         put_device(&card->ctl_dev);
1886         return 0;
1887 }
1888
1889 /*
1890  * create control core:
1891  * called from init.c
1892  */
1893 int snd_ctl_create(struct snd_card *card)
1894 {
1895         static struct snd_device_ops ops = {
1896                 .dev_free = snd_ctl_dev_free,
1897                 .dev_register = snd_ctl_dev_register,
1898                 .dev_disconnect = snd_ctl_dev_disconnect,
1899         };
1900         int err;
1901
1902         if (snd_BUG_ON(!card))
1903                 return -ENXIO;
1904         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1905                 return -ENXIO;
1906
1907         snd_device_initialize(&card->ctl_dev, card);
1908         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1909
1910         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1911         if (err < 0)
1912                 put_device(&card->ctl_dev);
1913         return err;
1914 }
1915
1916 /*
1917  * Frequently used control callbacks/helpers
1918  */
1919
1920 /**
1921  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1922  * callback with a mono channel
1923  * @kcontrol: the kcontrol instance
1924  * @uinfo: info to store
1925  *
1926  * This is a function that can be used as info callback for a standard
1927  * boolean control with a single mono channel.
1928  */
1929 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1930                               struct snd_ctl_elem_info *uinfo)
1931 {
1932         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1933         uinfo->count = 1;
1934         uinfo->value.integer.min = 0;
1935         uinfo->value.integer.max = 1;
1936         return 0;
1937 }
1938 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1939
1940 /**
1941  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1942  * callback with stereo two channels
1943  * @kcontrol: the kcontrol instance
1944  * @uinfo: info to store
1945  *
1946  * This is a function that can be used as info callback for a standard
1947  * boolean control with stereo two channels.
1948  */
1949 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1950                                 struct snd_ctl_elem_info *uinfo)
1951 {
1952         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1953         uinfo->count = 2;
1954         uinfo->value.integer.min = 0;
1955         uinfo->value.integer.max = 1;
1956         return 0;
1957 }
1958 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1959
1960 /**
1961  * snd_ctl_enum_info - fills the info structure for an enumerated control
1962  * @info: the structure to be filled
1963  * @channels: the number of the control's channels; often one
1964  * @items: the number of control values; also the size of @names
1965  * @names: an array containing the names of all control values
1966  *
1967  * Sets all required fields in @info to their appropriate values.
1968  * If the control's accessibility is not the default (readable and writable),
1969  * the caller has to fill @info->access.
1970  *
1971  * Return: Zero.
1972  */
1973 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1974                       unsigned int items, const char *const names[])
1975 {
1976         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1977         info->count = channels;
1978         info->value.enumerated.items = items;
1979         if (!items)
1980                 return 0;
1981         if (info->value.enumerated.item >= items)
1982                 info->value.enumerated.item = items - 1;
1983         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1984              "ALSA: too long item name '%s'\n",
1985              names[info->value.enumerated.item]);
1986         strlcpy(info->value.enumerated.name,
1987                 names[info->value.enumerated.item],
1988                 sizeof(info->value.enumerated.name));
1989         return 0;
1990 }
1991 EXPORT_SYMBOL(snd_ctl_enum_info);