sound/core/control.c

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