sound/core/control.c

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