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/sched/signal.h>
  29 #include <sound/core.h>
  30 #include <sound/minors.h>
  31 #include <sound/info.h>
  32 #include <sound/control.h>
  33
  34 /* max number of user-defined controls */
  35 #define MAX_USER_CONTROLS       32
  36 #define MAX_CONTROL_COUNT       1028
  37
  38 struct snd_kctl_ioctl {
  39         struct list_head list;          /* list of all ioctls */
  40         snd_kctl_ioctl_func_t fioctl;
  41 };
  42
  43 static DECLARE_RWSEM(snd_ioctl_rwsem);
  44 static LIST_HEAD(snd_control_ioctls);
  45 #ifdef CONFIG_COMPAT
  46 static LIST_HEAD(snd_control_compat_ioctls);
  47 #endif
  48
  49 static int snd_ctl_open(struct inode *inode, struct file *file)
  50 {
  51         unsigned long flags;
  52         struct snd_card *card;
  53         struct snd_ctl_file *ctl;
  54         int i, err;
  55
  56         err = nonseekable_open(inode, file);
  57         if (err < 0)
  58                 return err;
  59
  60         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  61         if (!card) {
  62                 err = -ENODEV;
  63                 goto __error1;
  64         }
  65         err = snd_card_file_add(card, file);
  66         if (err < 0) {
  67                 err = -ENODEV;
  68                 goto __error1;
  69         }
  70         if (!try_module_get(card->module)) {
  71                 err = -EFAULT;
  72                 goto __error2;
  73         }
  74         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  75         if (ctl == NULL) {
  76                 err = -ENOMEM;
  77                 goto __error;
  78         }
  79         INIT_LIST_HEAD(&ctl->events);
  80         init_waitqueue_head(&ctl->change_sleep);
  81         spin_lock_init(&ctl->read_lock);
  82         ctl->card = card;
  83         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  84                 ctl->preferred_subdevice[i] = -1;
  85         ctl->pid = get_pid(task_pid(current));
  86         file->private_data = ctl;
  87         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  88         list_add_tail(&ctl->list, &card->ctl_files);
  89         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  90         snd_card_unref(card);
  91         return 0;
  92
  93       __error:
  94         module_put(card->module);
  95       __error2:
  96         snd_card_file_remove(card, file);
  97       __error1:
  98         if (card)
  99                 snd_card_unref(card);
 100         return err;
 101 }
 102
 103 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 104 {
 105         unsigned long flags;
 106         struct snd_kctl_event *cread;
 107
 108         spin_lock_irqsave(&ctl->read_lock, flags);
 109         while (!list_empty(&ctl->events)) {
 110                 cread = snd_kctl_event(ctl->events.next);
 111                 list_del(&cread->list);
 112                 kfree(cread);
 113         }
 114         spin_unlock_irqrestore(&ctl->read_lock, flags);
 115 }
 116
 117 static int snd_ctl_release(struct inode *inode, struct file *file)
 118 {
 119         unsigned long flags;
 120         struct snd_card *card;
 121         struct snd_ctl_file *ctl;
 122         struct snd_kcontrol *control;
 123         unsigned int idx;
 124
 125         ctl = file->private_data;
 126         file->private_data = NULL;
 127         card = ctl->card;
 128         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 129         list_del(&ctl->list);
 130         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 131         down_write(&card->controls_rwsem);
 132         list_for_each_entry(control, &card->controls, list)
 133                 for (idx = 0; idx < control->count; idx++)
 134                         if (control->vd[idx].owner == ctl)
 135                                 control->vd[idx].owner = NULL;
 136         up_write(&card->controls_rwsem);
 137         snd_ctl_empty_read_queue(ctl);
 138         put_pid(ctl->pid);
 139         kfree(ctl);
 140         module_put(card->module);
 141         snd_card_file_remove(card, file);
 142         return 0;
 143 }
 144
 145 /**
 146  * snd_ctl_notify - Send notification to user-space for a control change
 147  * @card: the card to send notification
 148  * @mask: the event mask, SNDRV_CTL_EVENT_*
 149  * @id: the ctl element id to send notification
 150  *
 151  * This function adds an event record with the given id and mask, appends
 152  * to the list and wakes up the user-space for notification.  This can be
 153  * called in the atomic context.
 154  */
 155 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 156                     struct snd_ctl_elem_id *id)
 157 {
 158         unsigned long flags;
 159         struct snd_ctl_file *ctl;
 160         struct snd_kctl_event *ev;
 161
 162         if (snd_BUG_ON(!card || !id))
 163                 return;
 164         if (card->shutdown)
 165                 return;
 166         read_lock(&card->ctl_files_rwlock);
 167 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 168         card->mixer_oss_change_count++;
 169 #endif
 170         list_for_each_entry(ctl, &card->ctl_files, list) {
 171                 if (!ctl->subscribed)
 172                         continue;
 173                 spin_lock_irqsave(&ctl->read_lock, flags);
 174                 list_for_each_entry(ev, &ctl->events, list) {
 175                         if (ev->id.numid == id->numid) {
 176                                 ev->mask |= mask;
 177                                 goto _found;
 178                         }
 179                 }
 180                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 181                 if (ev) {
 182                         ev->id = *id;
 183                         ev->mask = mask;
 184                         list_add_tail(&ev->list, &ctl->events);
 185                 } else {
 186                         dev_err(card->dev, "No memory available to allocate event\n");
 187                 }
 188         _found:
 189                 wake_up(&ctl->change_sleep);
 190                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 191                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 192         }
 193         read_unlock(&card->ctl_files_rwlock);
 194 }
 195 EXPORT_SYMBOL(snd_ctl_notify);
 196
 197 /**
 198  * snd_ctl_new - create a new control instance with some elements
 199  * @kctl: the pointer to store new control instance
 200  * @count: the number of elements in this control
 201  * @access: the default access flags for elements in this control
 202  * @file: given when locking these elements
 203  *
 204  * Allocates a memory object for a new control instance. The instance has
 205  * elements as many as the given number (@count). Each element has given
 206  * access permissions (@access). Each element is locked when @file is given.
 207  *
 208  * Return: 0 on success, error code on failure
 209  */
 210 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 211                        unsigned int access, struct snd_ctl_file *file)
 212 {
 213         unsigned int size;
 214         unsigned int idx;
 215
 216         if (count == 0 || count > MAX_CONTROL_COUNT)
 217                 return -EINVAL;
 218
 219         size  = sizeof(struct snd_kcontrol);
 220         size += sizeof(struct snd_kcontrol_volatile) * count;
 221
 222         *kctl = kzalloc(size, GFP_KERNEL);
 223         if (!*kctl)
 224                 return -ENOMEM;
 225
 226         for (idx = 0; idx < count; idx++) {
 227                 (*kctl)->vd[idx].access = access;
 228                 (*kctl)->vd[idx].owner = file;
 229         }
 230         (*kctl)->count = count;
 231
 232         return 0;
 233 }
 234
 235 /**
 236  * snd_ctl_new1 - create a control instance from the template
 237  * @ncontrol: the initialization record
 238  * @private_data: the private data to set
 239  *
 240  * Allocates a new struct snd_kcontrol instance and initialize from the given
 241  * template.  When the access field of ncontrol is 0, it's assumed as
 242  * READWRITE access. When the count field is 0, it's assumes as one.
 243  *
 244  * Return: The pointer of the newly generated instance, or %NULL on failure.
 245  */
 246 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 247                                   void *private_data)
 248 {
 249         struct snd_kcontrol *kctl;
 250         unsigned int count;
 251         unsigned int access;
 252         int err;
 253
 254         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 255                 return NULL;
 256
 257         count = ncontrol->count;
 258         if (count == 0)
 259                 count = 1;
 260
 261         access = ncontrol->access;
 262         if (access == 0)
 263                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 264         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 265                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 266                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 267                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 268                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 269                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
 270
 271         err = snd_ctl_new(&kctl, count, access, NULL);
 272         if (err < 0)
 273                 return NULL;
 274
 275         /* The 'numid' member is decided when calling snd_ctl_add(). */
 276         kctl->id.iface = ncontrol->iface;
 277         kctl->id.device = ncontrol->device;
 278         kctl->id.subdevice = ncontrol->subdevice;
 279         if (ncontrol->name) {
 280                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 281                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 282                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 283                                 ncontrol->name, kctl->id.name);
 284         }
 285         kctl->id.index = ncontrol->index;
 286
 287         kctl->info = ncontrol->info;
 288         kctl->get = ncontrol->get;
 289         kctl->put = ncontrol->put;
 290         kctl->tlv.p = ncontrol->tlv.p;
 291
 292         kctl->private_value = ncontrol->private_value;
 293         kctl->private_data = private_data;
 294
 295         return kctl;
 296 }
 297 EXPORT_SYMBOL(snd_ctl_new1);
 298
 299 /**
 300  * snd_ctl_free_one - release the control instance
 301  * @kcontrol: the control instance
 302  *
 303  * Releases the control instance created via snd_ctl_new()
 304  * or snd_ctl_new1().
 305  * Don't call this after the control was added to the card.
 306  */
 307 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 308 {
 309         if (kcontrol) {
 310                 if (kcontrol->private_free)
 311                         kcontrol->private_free(kcontrol);
 312                 kfree(kcontrol);
 313         }
 314 }
 315 EXPORT_SYMBOL(snd_ctl_free_one);
 316
 317 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 318                                           unsigned int count)
 319 {
 320         struct snd_kcontrol *kctl;
 321
 322         /* Make sure that the ids assigned to the control do not wrap around */
 323         if (card->last_numid >= UINT_MAX - count)
 324                 card->last_numid = 0;
 325
 326         list_for_each_entry(kctl, &card->controls, list) {
 327                 if (kctl->id.numid < card->last_numid + 1 + count &&
 328                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 329                         card->last_numid = kctl->id.numid + kctl->count - 1;
 330                         return true;
 331                 }
 332         }
 333         return false;
 334 }
 335
 336 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 337 {
 338         unsigned int iter = 100000;
 339
 340         while (snd_ctl_remove_numid_conflict(card, count)) {
 341                 if (--iter == 0) {
 342                         /* this situation is very unlikely */
 343                         dev_err(card->dev, "unable to allocate new control numid\n");
 344                         return -ENOMEM;
 345                 }
 346         }
 347         return 0;
 348 }
 349
 350 /* add a new kcontrol object; call with card->controls_rwsem locked */
 351 static int __snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 352 {
 353         struct snd_ctl_elem_id id;
 354         unsigned int idx;
 355         unsigned int count;
 356
 357         id = kcontrol->id;
 358         if (id.index > UINT_MAX - kcontrol->count)
 359                 return -EINVAL;
 360
 361         if (snd_ctl_find_id(card, &id)) {
 362                 dev_err(card->dev,
 363                         "control %i:%i:%i:%s:%i is already present\n",
 364                         id.iface, id.device, id.subdevice, id.name, id.index);
 365                 return -EBUSY;
 366         }
 367
 368         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 369                 return -ENOMEM;
 370
 371         list_add_tail(&kcontrol->list, &card->controls);
 372         card->controls_count += kcontrol->count;
 373         kcontrol->id.numid = card->last_numid + 1;
 374         card->last_numid += kcontrol->count;
 375
 376         id = kcontrol->id;
 377         count = kcontrol->count;
 378         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 379                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 380
 381         return 0;
 382 }
 383
 384 /**
 385  * snd_ctl_add - add the control instance to the card
 386  * @card: the card instance
 387  * @kcontrol: the control instance to add
 388  *
 389  * Adds the control instance created via snd_ctl_new() or
 390  * snd_ctl_new1() to the given card. Assigns also an unique
 391  * numid used for fast search.
 392  *
 393  * It frees automatically the control which cannot be added.
 394  *
 395  * Return: Zero if successful, or a negative error code on failure.
 396  *
 397  */
 398 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 399 {
 400         int err = -EINVAL;
 401
 402         if (! kcontrol)
 403                 return err;
 404         if (snd_BUG_ON(!card || !kcontrol->info))
 405                 goto error;
 406
 407         down_write(&card->controls_rwsem);
 408         err = __snd_ctl_add(card, kcontrol);
 409         up_write(&card->controls_rwsem);
 410         if (err < 0)
 411                 goto error;
 412         return 0;
 413
 414  error:
 415         snd_ctl_free_one(kcontrol);
 416         return err;
 417 }
 418 EXPORT_SYMBOL(snd_ctl_add);
 419
 420 /**
 421  * snd_ctl_replace - replace the control instance of the card
 422  * @card: the card instance
 423  * @kcontrol: the control instance to replace
 424  * @add_on_replace: add the control if not already added
 425  *
 426  * Replaces the given control.  If the given control does not exist
 427  * and the add_on_replace flag is set, the control is added.  If the
 428  * control exists, it is destroyed first.
 429  *
 430  * It frees automatically the control which cannot be added or replaced.
 431  *
 432  * Return: Zero if successful, or a negative error code on failure.
 433  */
 434 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 435                     bool add_on_replace)
 436 {
 437         struct snd_ctl_elem_id id;
 438         unsigned int count;
 439         unsigned int idx;
 440         struct snd_kcontrol *old;
 441         int ret;
 442
 443         if (!kcontrol)
 444                 return -EINVAL;
 445         if (snd_BUG_ON(!card || !kcontrol->info)) {
 446                 ret = -EINVAL;
 447                 goto error;
 448         }
 449         id = kcontrol->id;
 450         down_write(&card->controls_rwsem);
 451         old = snd_ctl_find_id(card, &id);
 452         if (!old) {
 453                 if (add_on_replace)
 454                         goto add;
 455                 up_write(&card->controls_rwsem);
 456                 ret = -EINVAL;
 457                 goto error;
 458         }
 459         ret = snd_ctl_remove(card, old);
 460         if (ret < 0) {
 461                 up_write(&card->controls_rwsem);
 462                 goto error;
 463         }
 464 add:
 465         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 466                 up_write(&card->controls_rwsem);
 467                 ret = -ENOMEM;
 468                 goto error;
 469         }
 470         list_add_tail(&kcontrol->list, &card->controls);
 471         card->controls_count += kcontrol->count;
 472         kcontrol->id.numid = card->last_numid + 1;
 473         card->last_numid += kcontrol->count;
 474         id = kcontrol->id;
 475         count = kcontrol->count;
 476         up_write(&card->controls_rwsem);
 477         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 478                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 479         return 0;
 480
 481 error:
 482         snd_ctl_free_one(kcontrol);
 483         return ret;
 484 }
 485 EXPORT_SYMBOL(snd_ctl_replace);
 486
 487 /**
 488  * snd_ctl_remove - remove the control from the card and release it
 489  * @card: the card instance
 490  * @kcontrol: the control instance to remove
 491  *
 492  * Removes the control from the card and then releases the instance.
 493  * You don't need to call snd_ctl_free_one(). You must be in
 494  * the write lock - down_write(&card->controls_rwsem).
 495  *
 496  * Return: 0 if successful, or a negative error code on failure.
 497  */
 498 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 499 {
 500         struct snd_ctl_elem_id id;
 501         unsigned int idx;
 502
 503         if (snd_BUG_ON(!card || !kcontrol))
 504                 return -EINVAL;
 505         list_del(&kcontrol->list);
 506         card->controls_count -= kcontrol->count;
 507         id = kcontrol->id;
 508         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 509                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 510         snd_ctl_free_one(kcontrol);
 511         return 0;
 512 }
 513 EXPORT_SYMBOL(snd_ctl_remove);
 514
 515 /**
 516  * snd_ctl_remove_id - remove the control of the given id and release it
 517  * @card: the card instance
 518  * @id: the control id to remove
 519  *
 520  * Finds the control instance with the given id, removes it from the
 521  * card list and releases it.
 522  *
 523  * Return: 0 if successful, or a negative error code on failure.
 524  */
 525 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 526 {
 527         struct snd_kcontrol *kctl;
 528         int ret;
 529
 530         down_write(&card->controls_rwsem);
 531         kctl = snd_ctl_find_id(card, id);
 532         if (kctl == NULL) {
 533                 up_write(&card->controls_rwsem);
 534                 return -ENOENT;
 535         }
 536         ret = snd_ctl_remove(card, kctl);
 537         up_write(&card->controls_rwsem);
 538         return ret;
 539 }
 540 EXPORT_SYMBOL(snd_ctl_remove_id);
 541
 542 /**
 543  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 544  * @file: active control handle
 545  * @id: the control id to remove
 546  *
 547  * Finds the control instance with the given id, removes it from the
 548  * card list and releases it.
 549  *
 550  * Return: 0 if successful, or a negative error code on failure.
 551  */
 552 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 553                                    struct snd_ctl_elem_id *id)
 554 {
 555         struct snd_card *card = file->card;
 556         struct snd_kcontrol *kctl;
 557         int idx, ret;
 558
 559         down_write(&card->controls_rwsem);
 560         kctl = snd_ctl_find_id(card, id);
 561         if (kctl == NULL) {
 562                 ret = -ENOENT;
 563                 goto error;
 564         }
 565         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 566                 ret = -EINVAL;
 567                 goto error;
 568         }
 569         for (idx = 0; idx < kctl->count; idx++)
 570                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 571                         ret = -EBUSY;
 572                         goto error;
 573                 }
 574         ret = snd_ctl_remove(card, kctl);
 575         if (ret < 0)
 576                 goto error;
 577         card->user_ctl_count--;
 578 error:
 579         up_write(&card->controls_rwsem);
 580         return ret;
 581 }
 582
 583 /**
 584  * snd_ctl_activate_id - activate/inactivate the control of the given id
 585  * @card: the card instance
 586  * @id: the control id to activate/inactivate
 587  * @active: non-zero to activate
 588  *
 589  * Finds the control instance with the given id, and activate or
 590  * inactivate the control together with notification, if changed.
 591  * The given ID data is filled with full information.
 592  *
 593  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 594  */
 595 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 596                         int active)
 597 {
 598         struct snd_kcontrol *kctl;
 599         struct snd_kcontrol_volatile *vd;
 600         unsigned int index_offset;
 601         int ret;
 602
 603         down_write(&card->controls_rwsem);
 604         kctl = snd_ctl_find_id(card, id);
 605         if (kctl == NULL) {
 606                 ret = -ENOENT;
 607                 goto unlock;
 608         }
 609         index_offset = snd_ctl_get_ioff(kctl, id);
 610         vd = &kctl->vd[index_offset];
 611         ret = 0;
 612         if (active) {
 613                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 614                         goto unlock;
 615                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 616         } else {
 617                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 618                         goto unlock;
 619                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 620         }
 621         snd_ctl_build_ioff(id, kctl, index_offset);
 622         ret = 1;
 623  unlock:
 624         up_write(&card->controls_rwsem);
 625         if (ret > 0)
 626                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 627         return ret;
 628 }
 629 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 630
 631 /**
 632  * snd_ctl_rename_id - replace the id of a control on the card
 633  * @card: the card instance
 634  * @src_id: the old id
 635  * @dst_id: the new id
 636  *
 637  * Finds the control with the old id from the card, and replaces the
 638  * id with the new one.
 639  *
 640  * Return: Zero if successful, or a negative error code on failure.
 641  */
 642 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 643                       struct snd_ctl_elem_id *dst_id)
 644 {
 645         struct snd_kcontrol *kctl;
 646
 647         down_write(&card->controls_rwsem);
 648         kctl = snd_ctl_find_id(card, src_id);
 649         if (kctl == NULL) {
 650                 up_write(&card->controls_rwsem);
 651                 return -ENOENT;
 652         }
 653         kctl->id = *dst_id;
 654         kctl->id.numid = card->last_numid + 1;
 655         card->last_numid += kctl->count;
 656         up_write(&card->controls_rwsem);
 657         return 0;
 658 }
 659 EXPORT_SYMBOL(snd_ctl_rename_id);
 660
 661 /**
 662  * snd_ctl_find_numid - find the control instance with the given number-id
 663  * @card: the card instance
 664  * @numid: the number-id to search
 665  *
 666  * Finds the control instance with the given number-id from the card.
 667  *
 668  * The caller must down card->controls_rwsem before calling this function
 669  * (if the race condition can happen).
 670  *
 671  * Return: The pointer of the instance if found, or %NULL if not.
 672  *
 673  */
 674 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 675 {
 676         struct snd_kcontrol *kctl;
 677
 678         if (snd_BUG_ON(!card || !numid))
 679                 return NULL;
 680         list_for_each_entry(kctl, &card->controls, list) {
 681                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 682                         return kctl;
 683         }
 684         return NULL;
 685 }
 686 EXPORT_SYMBOL(snd_ctl_find_numid);
 687
 688 /**
 689  * snd_ctl_find_id - find the control instance with the given id
 690  * @card: the card instance
 691  * @id: the id to search
 692  *
 693  * Finds the control instance with the given id from the card.
 694  *
 695  * The caller must down card->controls_rwsem before calling this function
 696  * (if the race condition can happen).
 697  *
 698  * Return: The pointer of the instance if found, or %NULL if not.
 699  *
 700  */
 701 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 702                                      struct snd_ctl_elem_id *id)
 703 {
 704         struct snd_kcontrol *kctl;
 705
 706         if (snd_BUG_ON(!card || !id))
 707                 return NULL;
 708         if (id->numid != 0)
 709                 return snd_ctl_find_numid(card, id->numid);
 710         list_for_each_entry(kctl, &card->controls, list) {
 711                 if (kctl->id.iface != id->iface)
 712                         continue;
 713                 if (kctl->id.device != id->device)
 714                         continue;
 715                 if (kctl->id.subdevice != id->subdevice)
 716                         continue;
 717                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 718                         continue;
 719                 if (kctl->id.index > id->index)
 720                         continue;
 721                 if (kctl->id.index + kctl->count <= id->index)
 722                         continue;
 723                 return kctl;
 724         }
 725         return NULL;
 726 }
 727 EXPORT_SYMBOL(snd_ctl_find_id);
 728
 729 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 730                              unsigned int cmd, void __user *arg)
 731 {
 732         struct snd_ctl_card_info *info;
 733
 734         info = kzalloc(sizeof(*info), GFP_KERNEL);
 735         if (! info)
 736                 return -ENOMEM;
 737         down_read(&snd_ioctl_rwsem);
 738         info->card = card->number;
 739         strlcpy(info->id, card->id, sizeof(info->id));
 740         strlcpy(info->driver, card->driver, sizeof(info->driver));
 741         strlcpy(info->name, card->shortname, sizeof(info->name));
 742         strlcpy(info->longname, card->longname, sizeof(info->longname));
 743         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 744         strlcpy(info->components, card->components, sizeof(info->components));
 745         up_read(&snd_ioctl_rwsem);
 746         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 747                 kfree(info);
 748                 return -EFAULT;
 749         }
 750         kfree(info);
 751         return 0;
 752 }
 753
 754 static int snd_ctl_elem_list(struct snd_card *card,
 755                              struct snd_ctl_elem_list __user *_list)
 756 {
 757         struct snd_ctl_elem_list list;
 758         struct snd_kcontrol *kctl;
 759         struct snd_ctl_elem_id id;
 760         unsigned int offset, space, jidx;
 761         int err = 0;
 762
 763         if (copy_from_user(&list, _list, sizeof(list)))
 764                 return -EFAULT;
 765         offset = list.offset;
 766         space = list.space;
 767
 768         down_read(&card->controls_rwsem);
 769         list.count = card->controls_count;
 770         list.used = 0;
 771         if (space > 0) {
 772                 list_for_each_entry(kctl, &card->controls, list) {
 773                         if (offset >= kctl->count) {
 774                                 offset -= kctl->count;
 775                                 continue;
 776                         }
 777                         for (jidx = offset; jidx < kctl->count; jidx++) {
 778                                 snd_ctl_build_ioff(&id, kctl, jidx);
 779                                 if (copy_to_user(list.pids + list.used, &id,
 780                                                  sizeof(id))) {
 781                                         err = -EFAULT;
 782                                         goto out;
 783                                 }
 784                                 list.used++;
 785                                 if (!--space)
 786                                         goto out;
 787                         }
 788                         offset = 0;
 789                 }
 790         }
 791  out:
 792         up_read(&card->controls_rwsem);
 793         if (!err && copy_to_user(_list, &list, sizeof(list)))
 794                 err = -EFAULT;
 795         return err;
 796 }
 797
 798 static bool validate_element_member_dimension(struct snd_ctl_elem_info *info)
 799 {
 800         unsigned int members;
 801         unsigned int i;
 802
 803         if (info->dimen.d[0] == 0)
 804                 return true;
 805
 806         members = 1;
 807         for (i = 0; i < ARRAY_SIZE(info->dimen.d); ++i) {
 808                 if (info->dimen.d[i] == 0)
 809                         break;
 810                 members *= info->dimen.d[i];
 811
 812                 /*
 813                  * info->count should be validated in advance, to guarantee
 814                  * calculation soundness.
 815                  */
 816                 if (members > info->count)
 817                         return false;
 818         }
 819
 820         for (++i; i < ARRAY_SIZE(info->dimen.d); ++i) {
 821                 if (info->dimen.d[i] > 0)
 822                         return false;
 823         }
 824
 825         return members == info->count;
 826 }
 827
 828 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 829                              struct snd_ctl_elem_info *info)
 830 {
 831         struct snd_card *card = ctl->card;
 832         struct snd_kcontrol *kctl;
 833         struct snd_kcontrol_volatile *vd;
 834         unsigned int index_offset;
 835         int result;
 836
 837         down_read(&card->controls_rwsem);
 838         kctl = snd_ctl_find_id(card, &info->id);
 839         if (kctl == NULL) {
 840                 up_read(&card->controls_rwsem);
 841                 return -ENOENT;
 842         }
 843 #ifdef CONFIG_SND_DEBUG
 844         info->access = 0;
 845 #endif
 846         result = kctl->info(kctl, info);
 847         if (result >= 0) {
 848                 snd_BUG_ON(info->access);
 849                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 850                 vd = &kctl->vd[index_offset];
 851                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 852                 info->access = vd->access;
 853                 if (vd->owner) {
 854                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 855                         if (vd->owner == ctl)
 856                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 857                         info->owner = pid_vnr(vd->owner->pid);
 858                 } else {
 859                         info->owner = -1;
 860                 }
 861         }
 862         up_read(&card->controls_rwsem);
 863         return result;
 864 }
 865
 866 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 867                                   struct snd_ctl_elem_info __user *_info)
 868 {
 869         struct snd_ctl_elem_info info;
 870         int result;
 871
 872         if (copy_from_user(&info, _info, sizeof(info)))
 873                 return -EFAULT;
 874         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 875         if (result < 0)
 876                 return result;
 877         result = snd_ctl_elem_info(ctl, &info);
 878         if (result < 0)
 879                 return result;
 880         if (copy_to_user(_info, &info, sizeof(info)))
 881                 return -EFAULT;
 882         return result;
 883 }
 884
 885 static int snd_ctl_elem_read(struct snd_card *card,
 886                              struct snd_ctl_elem_value *control)
 887 {
 888         struct snd_kcontrol *kctl;
 889         struct snd_kcontrol_volatile *vd;
 890         unsigned int index_offset;
 891
 892         kctl = snd_ctl_find_id(card, &control->id);
 893         if (kctl == NULL)
 894                 return -ENOENT;
 895
 896         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 897         vd = &kctl->vd[index_offset];
 898         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
 899                 return -EPERM;
 900
 901         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 902         return kctl->get(kctl, control);
 903 }
 904
 905 static int snd_ctl_elem_read_user(struct snd_card *card,
 906                                   struct snd_ctl_elem_value __user *_control)
 907 {
 908         struct snd_ctl_elem_value *control;
 909         int result;
 910
 911         control = memdup_user(_control, sizeof(*control));
 912         if (IS_ERR(control))
 913                 return PTR_ERR(control);
 914
 915         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 916         if (result < 0)
 917                 goto error;
 918
 919         down_read(&card->controls_rwsem);
 920         result = snd_ctl_elem_read(card, control);
 921         up_read(&card->controls_rwsem);
 922         if (result < 0)
 923                 goto error;
 924
 925         if (copy_to_user(_control, control, sizeof(*control)))
 926                 result = -EFAULT;
 927  error:
 928         kfree(control);
 929         return result;
 930 }
 931
 932 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 933                               struct snd_ctl_elem_value *control)
 934 {
 935         struct snd_kcontrol *kctl;
 936         struct snd_kcontrol_volatile *vd;
 937         unsigned int index_offset;
 938         int result;
 939
 940         kctl = snd_ctl_find_id(card, &control->id);
 941         if (kctl == NULL)
 942                 return -ENOENT;
 943
 944         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 945         vd = &kctl->vd[index_offset];
 946         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
 947             (file && vd->owner && vd->owner != file)) {
 948                 return -EPERM;
 949         }
 950
 951         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 952         result = kctl->put(kctl, control);
 953         if (result < 0)
 954                 return result;
 955
 956         if (result > 0) {
 957                 struct snd_ctl_elem_id id = control->id;
 958                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 959         }
 960
 961         return 0;
 962 }
 963
 964 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 965                                    struct snd_ctl_elem_value __user *_control)
 966 {
 967         struct snd_ctl_elem_value *control;
 968         struct snd_card *card;
 969         int result;
 970
 971         control = memdup_user(_control, sizeof(*control));
 972         if (IS_ERR(control))
 973                 return PTR_ERR(control);
 974
 975         card = file->card;
 976         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 977         if (result < 0)
 978                 goto error;
 979
 980         down_write(&card->controls_rwsem);
 981         result = snd_ctl_elem_write(card, file, control);
 982         up_write(&card->controls_rwsem);
 983         if (result < 0)
 984                 goto error;
 985
 986         if (copy_to_user(_control, control, sizeof(*control)))
 987                 result = -EFAULT;
 988  error:
 989         kfree(control);
 990         return result;
 991 }
 992
 993 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 994                              struct snd_ctl_elem_id __user *_id)
 995 {
 996         struct snd_card *card = file->card;
 997         struct snd_ctl_elem_id id;
 998         struct snd_kcontrol *kctl;
 999         struct snd_kcontrol_volatile *vd;
1000         int result;
1001
1002         if (copy_from_user(&id, _id, sizeof(id)))
1003                 return -EFAULT;
1004         down_write(&card->controls_rwsem);
1005         kctl = snd_ctl_find_id(card, &id);
1006         if (kctl == NULL) {
1007                 result = -ENOENT;
1008         } else {
1009                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1010                 if (vd->owner != NULL)
1011                         result = -EBUSY;
1012                 else {
1013                         vd->owner = file;
1014                         result = 0;
1015                 }
1016         }
1017         up_write(&card->controls_rwsem);
1018         return result;
1019 }
1020
1021 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1022                                struct snd_ctl_elem_id __user *_id)
1023 {
1024         struct snd_card *card = file->card;
1025         struct snd_ctl_elem_id id;
1026         struct snd_kcontrol *kctl;
1027         struct snd_kcontrol_volatile *vd;
1028         int result;
1029
1030         if (copy_from_user(&id, _id, sizeof(id)))
1031                 return -EFAULT;
1032         down_write(&card->controls_rwsem);
1033         kctl = snd_ctl_find_id(card, &id);
1034         if (kctl == NULL) {
1035                 result = -ENOENT;
1036         } else {
1037                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1038                 if (vd->owner == NULL)
1039                         result = -EINVAL;
1040                 else if (vd->owner != file)
1041                         result = -EPERM;
1042                 else {
1043                         vd->owner = NULL;
1044                         result = 0;
1045                 }
1046         }
1047         up_write(&card->controls_rwsem);
1048         return result;
1049 }
1050
1051 struct user_element {
1052         struct snd_ctl_elem_info info;
1053         struct snd_card *card;
1054         char *elem_data;                /* element data */
1055         unsigned long elem_data_size;   /* size of element data in bytes */
1056         void *tlv_data;                 /* TLV data */
1057         unsigned long tlv_data_size;    /* TLV data size */
1058         void *priv_data;                /* private data (like strings for enumerated type) */
1059 };
1060
1061 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1062                                   struct snd_ctl_elem_info *uinfo)
1063 {
1064         struct user_element *ue = kcontrol->private_data;
1065         unsigned int offset;
1066
1067         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1068         *uinfo = ue->info;
1069         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1070
1071         return 0;
1072 }
1073
1074 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1075                                        struct snd_ctl_elem_info *uinfo)
1076 {
1077         struct user_element *ue = kcontrol->private_data;
1078         const char *names;
1079         unsigned int item;
1080         unsigned int offset;
1081
1082         item = uinfo->value.enumerated.item;
1083
1084         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1085         *uinfo = ue->info;
1086         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1087
1088         item = min(item, uinfo->value.enumerated.items - 1);
1089         uinfo->value.enumerated.item = item;
1090
1091         names = ue->priv_data;
1092         for (; item > 0; --item)
1093                 names += strlen(names) + 1;
1094         strcpy(uinfo->value.enumerated.name, names);
1095
1096         return 0;
1097 }
1098
1099 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1100                                  struct snd_ctl_elem_value *ucontrol)
1101 {
1102         struct user_element *ue = kcontrol->private_data;
1103         unsigned int size = ue->elem_data_size;
1104         char *src = ue->elem_data +
1105                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1106
1107         memcpy(&ucontrol->value, src, size);
1108         return 0;
1109 }
1110
1111 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1112                                  struct snd_ctl_elem_value *ucontrol)
1113 {
1114         int change;
1115         struct user_element *ue = kcontrol->private_data;
1116         unsigned int size = ue->elem_data_size;
1117         char *dst = ue->elem_data +
1118                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1119
1120         change = memcmp(&ucontrol->value, dst, size) != 0;
1121         if (change)
1122                 memcpy(dst, &ucontrol->value, size);
1123         return change;
1124 }
1125
1126 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1127                             unsigned int size)
1128 {
1129         struct user_element *ue = kctl->private_data;
1130         unsigned int *container;
1131         struct snd_ctl_elem_id id;
1132         unsigned int mask = 0;
1133         int i;
1134         int change;
1135
1136         if (size > 1024 * 128)  /* sane value */
1137                 return -EINVAL;
1138
1139         container = memdup_user(buf, size);
1140         if (IS_ERR(container))
1141                 return PTR_ERR(container);
1142
1143         change = ue->tlv_data_size != size;
1144         if (!change)
1145                 change = memcmp(ue->tlv_data, container, size) != 0;
1146         if (!change) {
1147                 kfree(container);
1148                 return 0;
1149         }
1150
1151         if (ue->tlv_data == NULL) {
1152                 /* Now TLV data is available. */
1153                 for (i = 0; i < kctl->count; ++i)
1154                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1155                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1156         }
1157
1158         kfree(ue->tlv_data);
1159         ue->tlv_data = container;
1160         ue->tlv_data_size = size;
1161
1162         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1163         for (i = 0; i < kctl->count; ++i) {
1164                 snd_ctl_build_ioff(&id, kctl, i);
1165                 snd_ctl_notify(ue->card, mask, &id);
1166         }
1167
1168         return change;
1169 }
1170
1171 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1172                          unsigned int size)
1173 {
1174         struct user_element *ue = kctl->private_data;
1175
1176         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1177                 return -ENXIO;
1178
1179         if (size < ue->tlv_data_size)
1180                 return -ENOSPC;
1181
1182         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1183                 return -EFAULT;
1184
1185         return 0;
1186 }
1187
1188 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1189                                  unsigned int size, unsigned int __user *buf)
1190 {
1191         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1192                 return replace_user_tlv(kctl, buf, size);
1193         else
1194                 return read_user_tlv(kctl, buf, size);
1195 }
1196
1197 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1198 {
1199         char *names, *p;
1200         size_t buf_len, name_len;
1201         unsigned int i;
1202         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1203
1204         if (ue->info.value.enumerated.names_length > 64 * 1024)
1205                 return -EINVAL;
1206
1207         names = memdup_user((const void __user *)user_ptrval,
1208                 ue->info.value.enumerated.names_length);
1209         if (IS_ERR(names))
1210                 return PTR_ERR(names);
1211
1212         /* check that there are enough valid names */
1213         buf_len = ue->info.value.enumerated.names_length;
1214         p = names;
1215         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1216                 name_len = strnlen(p, buf_len);
1217                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1218                         kfree(names);
1219                         return -EINVAL;
1220                 }
1221                 p += name_len + 1;
1222                 buf_len -= name_len + 1;
1223         }
1224
1225         ue->priv_data = names;
1226         ue->info.value.enumerated.names_ptr = 0;
1227
1228         return 0;
1229 }
1230
1231 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1232 {
1233         struct user_element *ue = kcontrol->private_data;
1234
1235         kfree(ue->tlv_data);
1236         kfree(ue->priv_data);
1237         kfree(ue);
1238 }
1239
1240 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1241                             struct snd_ctl_elem_info *info, int replace)
1242 {
1243         /* The capacity of struct snd_ctl_elem_value.value.*/
1244         static const unsigned int value_sizes[] = {
1245                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
1246                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
1247                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1248                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
1249                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
1250                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1251         };
1252         static const unsigned int max_value_counts[] = {
1253                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
1254                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
1255                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1256                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
1257                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
1258                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1259         };
1260         struct snd_card *card = file->card;
1261         struct snd_kcontrol *kctl;
1262         unsigned int count;
1263         unsigned int access;
1264         long private_size;
1265         struct user_element *ue;
1266         unsigned int offset;
1267         int err;
1268
1269         if (!*info->id.name)
1270                 return -EINVAL;
1271         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1272                 return -EINVAL;
1273
1274         /* Delete a control to replace them if needed. */
1275         if (replace) {
1276                 info->id.numid = 0;
1277                 err = snd_ctl_remove_user_ctl(file, &info->id);
1278                 if (err)
1279                         return err;
1280         }
1281
1282         /*
1283          * The number of userspace controls are counted control by control,
1284          * not element by element.
1285          */
1286         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1287                 return -ENOMEM;
1288
1289         /* Check the number of elements for this userspace control. */
1290         count = info->owner;
1291         if (count == 0)
1292                 count = 1;
1293
1294         /* Arrange access permissions if needed. */
1295         access = info->access;
1296         if (access == 0)
1297                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1298         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1299                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1300                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1301
1302         /* In initial state, nothing is available as TLV container. */
1303         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1304                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1305         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1306
1307         /*
1308          * Check information and calculate the size of data specific to
1309          * this userspace control.
1310          */
1311         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1312             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1313                 return -EINVAL;
1314         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1315             info->value.enumerated.items == 0)
1316                 return -EINVAL;
1317         if (info->count < 1 ||
1318             info->count > max_value_counts[info->type])
1319                 return -EINVAL;
1320         if (!validate_element_member_dimension(info))
1321                 return -EINVAL;
1322         private_size = value_sizes[info->type] * info->count;
1323
1324         /*
1325          * Keep memory object for this userspace control. After passing this
1326          * code block, the instance should be freed by snd_ctl_free_one().
1327          *
1328          * Note that these elements in this control are locked.
1329          */
1330         err = snd_ctl_new(&kctl, count, access, file);
1331         if (err < 0)
1332                 return err;
1333         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1334         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1335                                      GFP_KERNEL);
1336         if (kctl->private_data == NULL) {
1337                 kfree(kctl);
1338                 return -ENOMEM;
1339         }
1340         kctl->private_free = snd_ctl_elem_user_free;
1341
1342         /* Set private data for this userspace control. */
1343         ue = (struct user_element *)kctl->private_data;
1344         ue->card = card;
1345         ue->info = *info;
1346         ue->info.access = 0;
1347         ue->elem_data = (char *)ue + sizeof(*ue);
1348         ue->elem_data_size = private_size;
1349         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1350                 err = snd_ctl_elem_init_enum_names(ue);
1351                 if (err < 0) {
1352                         snd_ctl_free_one(kctl);
1353                         return err;
1354                 }
1355         }
1356
1357         /* Set callback functions. */
1358         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1359                 kctl->info = snd_ctl_elem_user_enum_info;
1360         else
1361                 kctl->info = snd_ctl_elem_user_info;
1362         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1363                 kctl->get = snd_ctl_elem_user_get;
1364         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1365                 kctl->put = snd_ctl_elem_user_put;
1366         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1367                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1368
1369         /* This function manage to free the instance on failure. */
1370         down_write(&card->controls_rwsem);
1371         err = __snd_ctl_add(card, kctl);
1372         if (err < 0) {
1373                 snd_ctl_free_one(kctl);
1374                 goto unlock;
1375         }
1376         offset = snd_ctl_get_ioff(kctl, &info->id);
1377         snd_ctl_build_ioff(&info->id, kctl, offset);
1378         /*
1379          * Here we cannot fill any field for the number of elements added by
1380          * this operation because there're no specific fields. The usage of
1381          * 'owner' field for this purpose may cause any bugs to userspace
1382          * applications because the field originally means PID of a process
1383          * which locks the element.
1384          */
1385
1386         card->user_ctl_count++;
1387
1388  unlock:
1389         up_write(&card->controls_rwsem);
1390         return err;
1391 }
1392
1393 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1394                                  struct snd_ctl_elem_info __user *_info, int replace)
1395 {
1396         struct snd_ctl_elem_info info;
1397         int err;
1398
1399         if (copy_from_user(&info, _info, sizeof(info)))
1400                 return -EFAULT;
1401         err = snd_ctl_elem_add(file, &info, replace);
1402         if (err < 0)
1403                 return err;
1404         if (copy_to_user(_info, &info, sizeof(info))) {
1405                 snd_ctl_remove_user_ctl(file, &info.id);
1406                 return -EFAULT;
1407         }
1408
1409         return 0;
1410 }
1411
1412 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1413                                struct snd_ctl_elem_id __user *_id)
1414 {
1415         struct snd_ctl_elem_id id;
1416
1417         if (copy_from_user(&id, _id, sizeof(id)))
1418                 return -EFAULT;
1419         return snd_ctl_remove_user_ctl(file, &id);
1420 }
1421
1422 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1423 {
1424         int subscribe;
1425         if (get_user(subscribe, ptr))
1426                 return -EFAULT;
1427         if (subscribe < 0) {
1428                 subscribe = file->subscribed;
1429                 if (put_user(subscribe, ptr))
1430                         return -EFAULT;
1431                 return 0;
1432         }
1433         if (subscribe) {
1434                 file->subscribed = 1;
1435                 return 0;
1436         } else if (file->subscribed) {
1437                 snd_ctl_empty_read_queue(file);
1438                 file->subscribed = 0;
1439         }
1440         return 0;
1441 }
1442
1443 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1444                             struct snd_kcontrol *kctl,
1445                             struct snd_ctl_elem_id *id,
1446                             unsigned int __user *buf, unsigned int size)
1447 {
1448         static const struct {
1449                 int op;
1450                 int perm;
1451         } pairs[] = {
1452                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1453                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1454                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1455         };
1456         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1457         int i;
1458
1459         /* Check support of the request for this element. */
1460         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1461                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1462                         break;
1463         }
1464         if (i == ARRAY_SIZE(pairs))
1465                 return -ENXIO;
1466
1467         if (kctl->tlv.c == NULL)
1468                 return -ENXIO;
1469
1470         /* Write and command operations are not allowed for locked element. */
1471         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1472             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 *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 unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1681 {
1682         unsigned int 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 |= POLLIN | POLLRDNORM;
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);