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 <[email protected]>
   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 /* check whether the given id is contained in the given kctl */
 369 static bool elem_id_matches(const struct snd_kcontrol *kctl,
 370                             const struct snd_ctl_elem_id *id)
 371 {
 372         return kctl->id.iface == id->iface &&
 373                 kctl->id.device == id->device &&
 374                 kctl->id.subdevice == id->subdevice &&
 375                 !strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) &&
 376                 kctl->id.index <= id->index &&
 377                 kctl->id.index + kctl->count > id->index;
 378 }
 379
 380 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 381 /* Compute a hash key for the corresponding ctl id
 382  * It's for the name lookup, hence the numid is excluded.
 383  * The hash key is bound in LONG_MAX to be used for Xarray key.
 384  */
 385 #define MULTIPLIER      37
 386 static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id)
 387 {
 388         int i;
 389         unsigned long h;
 390
 391         h = id->iface;
 392         h = MULTIPLIER * h + id->device;
 393         h = MULTIPLIER * h + id->subdevice;
 394         for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++)
 395                 h = MULTIPLIER * h + id->name[i];
 396         h = MULTIPLIER * h + id->index;
 397         h &= LONG_MAX;
 398         return h;
 399 }
 400
 401 /* add hash entries to numid and ctl xarray tables */
 402 static void add_hash_entries(struct snd_card *card,
 403                              struct snd_kcontrol *kcontrol)
 404 {
 405         struct snd_ctl_elem_id id = kcontrol->id;
 406         int i;
 407
 408         xa_store_range(&card->ctl_numids, kcontrol->id.numid,
 409                        kcontrol->id.numid + kcontrol->count - 1,
 410                        kcontrol, GFP_KERNEL);
 411
 412         for (i = 0; i < kcontrol->count; i++) {
 413                 id.index = kcontrol->id.index + i;
 414                 if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id),
 415                               kcontrol, GFP_KERNEL)) {
 416                         /* skip hash for this entry, noting we had collision */
 417                         card->ctl_hash_collision = true;
 418                         dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n",
 419                                 id.iface, id.name, id.index);
 420                 }
 421         }
 422 }
 423
 424 /* remove hash entries that have been added */
 425 static void remove_hash_entries(struct snd_card *card,
 426                                 struct snd_kcontrol *kcontrol)
 427 {
 428         struct snd_ctl_elem_id id = kcontrol->id;
 429         struct snd_kcontrol *matched;
 430         unsigned long h;
 431         int i;
 432
 433         for (i = 0; i < kcontrol->count; i++) {
 434                 xa_erase(&card->ctl_numids, id.numid);
 435                 h = get_ctl_id_hash(&id);
 436                 matched = xa_load(&card->ctl_hash, h);
 437                 if (matched && (matched == kcontrol ||
 438                                 elem_id_matches(matched, &id)))
 439                         xa_erase(&card->ctl_hash, h);
 440                 id.index++;
 441                 id.numid++;
 442         }
 443 }
 444 #else /* CONFIG_SND_CTL_FAST_LOOKUP */
 445 static inline void add_hash_entries(struct snd_card *card,
 446                                     struct snd_kcontrol *kcontrol)
 447 {
 448 }
 449 static inline void remove_hash_entries(struct snd_card *card,
 450                                        struct snd_kcontrol *kcontrol)
 451 {
 452 }
 453 #endif /* CONFIG_SND_CTL_FAST_LOOKUP */
 454
 455 enum snd_ctl_add_mode {
 456         CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
 457 };
 458
 459 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
 460 static int __snd_ctl_add_replace(struct snd_card *card,
 461                                  struct snd_kcontrol *kcontrol,
 462                                  enum snd_ctl_add_mode mode)
 463 {
 464         struct snd_ctl_elem_id id;
 465         unsigned int idx;
 466         struct snd_kcontrol *old;
 467         int err;
 468
 469         id = kcontrol->id;
 470         if (id.index > UINT_MAX - kcontrol->count)
 471                 return -EINVAL;
 472
 473         old = snd_ctl_find_id(card, &id);
 474         if (!old) {
 475                 if (mode == CTL_REPLACE)
 476                         return -EINVAL;
 477         } else {
 478                 if (mode == CTL_ADD_EXCLUSIVE) {
 479                         dev_err(card->dev,
 480                                 "control %i:%i:%i:%s:%i is already present\n",
 481                                 id.iface, id.device, id.subdevice, id.name,
 482                                 id.index);
 483                         return -EBUSY;
 484                 }
 485
 486                 err = snd_ctl_remove(card, old);
 487                 if (err < 0)
 488                         return err;
 489         }
 490
 491         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 492                 return -ENOMEM;
 493
 494         list_add_tail(&kcontrol->list, &card->controls);
 495         card->controls_count += kcontrol->count;
 496         kcontrol->id.numid = card->last_numid + 1;
 497         card->last_numid += kcontrol->count;
 498
 499         add_hash_entries(card, kcontrol);
 500
 501         for (idx = 0; idx < kcontrol->count; idx++)
 502                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
 503
 504         return 0;
 505 }
 506
 507 static int snd_ctl_add_replace(struct snd_card *card,
 508                                struct snd_kcontrol *kcontrol,
 509                                enum snd_ctl_add_mode mode)
 510 {
 511         int err = -EINVAL;
 512
 513         if (! kcontrol)
 514                 return err;
 515         if (snd_BUG_ON(!card || !kcontrol->info))
 516                 goto error;
 517
 518         down_write(&card->controls_rwsem);
 519         err = __snd_ctl_add_replace(card, kcontrol, mode);
 520         up_write(&card->controls_rwsem);
 521         if (err < 0)
 522                 goto error;
 523         return 0;
 524
 525  error:
 526         snd_ctl_free_one(kcontrol);
 527         return err;
 528 }
 529
 530 /**
 531  * snd_ctl_add - add the control instance to the card
 532  * @card: the card instance
 533  * @kcontrol: the control instance to add
 534  *
 535  * Adds the control instance created via snd_ctl_new() or
 536  * snd_ctl_new1() to the given card. Assigns also an unique
 537  * numid used for fast search.
 538  *
 539  * It frees automatically the control which cannot be added.
 540  *
 541  * Return: Zero if successful, or a negative error code on failure.
 542  *
 543  */
 544 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 545 {
 546         return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
 547 }
 548 EXPORT_SYMBOL(snd_ctl_add);
 549
 550 /**
 551  * snd_ctl_replace - replace the control instance of the card
 552  * @card: the card instance
 553  * @kcontrol: the control instance to replace
 554  * @add_on_replace: add the control if not already added
 555  *
 556  * Replaces the given control.  If the given control does not exist
 557  * and the add_on_replace flag is set, the control is added.  If the
 558  * control exists, it is destroyed first.
 559  *
 560  * It frees automatically the control which cannot be added or replaced.
 561  *
 562  * Return: Zero if successful, or a negative error code on failure.
 563  */
 564 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 565                     bool add_on_replace)
 566 {
 567         return snd_ctl_add_replace(card, kcontrol,
 568                                    add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
 569 }
 570 EXPORT_SYMBOL(snd_ctl_replace);
 571
 572 static int __snd_ctl_remove(struct snd_card *card,
 573                             struct snd_kcontrol *kcontrol,
 574                             bool remove_hash)
 575 {
 576         unsigned int idx;
 577
 578         if (snd_BUG_ON(!card || !kcontrol))
 579                 return -EINVAL;
 580         list_del(&kcontrol->list);
 581
 582         if (remove_hash)
 583                 remove_hash_entries(card, kcontrol);
 584
 585         card->controls_count -= kcontrol->count;
 586         for (idx = 0; idx < kcontrol->count; idx++)
 587                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
 588         snd_ctl_free_one(kcontrol);
 589         return 0;
 590 }
 591
 592 /**
 593  * snd_ctl_remove - remove the control from the card and release it
 594  * @card: the card instance
 595  * @kcontrol: the control instance to remove
 596  *
 597  * Removes the control from the card and then releases the instance.
 598  * You don't need to call snd_ctl_free_one(). You must be in
 599  * the write lock - down_write(&card->controls_rwsem).
 600  *
 601  * Return: 0 if successful, or a negative error code on failure.
 602  */
 603 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 604 {
 605         return __snd_ctl_remove(card, kcontrol, true);
 606 }
 607 EXPORT_SYMBOL(snd_ctl_remove);
 608
 609 /**
 610  * snd_ctl_remove_id - remove the control of the given id and release it
 611  * @card: the card instance
 612  * @id: the control id to remove
 613  *
 614  * Finds the control instance with the given id, removes it from the
 615  * card list and releases it.
 616  *
 617  * Return: 0 if successful, or a negative error code on failure.
 618  */
 619 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 620 {
 621         struct snd_kcontrol *kctl;
 622         int ret;
 623
 624         down_write(&card->controls_rwsem);
 625         kctl = snd_ctl_find_id(card, id);
 626         if (kctl == NULL) {
 627                 up_write(&card->controls_rwsem);
 628                 return -ENOENT;
 629         }
 630         ret = snd_ctl_remove(card, kctl);
 631         up_write(&card->controls_rwsem);
 632         return ret;
 633 }
 634 EXPORT_SYMBOL(snd_ctl_remove_id);
 635
 636 /**
 637  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 638  * @file: active control handle
 639  * @id: the control id to remove
 640  *
 641  * Finds the control instance with the given id, removes it from the
 642  * card list and releases it.
 643  *
 644  * Return: 0 if successful, or a negative error code on failure.
 645  */
 646 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 647                                    struct snd_ctl_elem_id *id)
 648 {
 649         struct snd_card *card = file->card;
 650         struct snd_kcontrol *kctl;
 651         int idx, ret;
 652
 653         down_write(&card->controls_rwsem);
 654         kctl = snd_ctl_find_id(card, id);
 655         if (kctl == NULL) {
 656                 ret = -ENOENT;
 657                 goto error;
 658         }
 659         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 660                 ret = -EINVAL;
 661                 goto error;
 662         }
 663         for (idx = 0; idx < kctl->count; idx++)
 664                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 665                         ret = -EBUSY;
 666                         goto error;
 667                 }
 668         ret = snd_ctl_remove(card, kctl);
 669 error:
 670         up_write(&card->controls_rwsem);
 671         return ret;
 672 }
 673
 674 /**
 675  * snd_ctl_activate_id - activate/inactivate the control of the given id
 676  * @card: the card instance
 677  * @id: the control id to activate/inactivate
 678  * @active: non-zero to activate
 679  *
 680  * Finds the control instance with the given id, and activate or
 681  * inactivate the control together with notification, if changed.
 682  * The given ID data is filled with full information.
 683  *
 684  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 685  */
 686 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 687                         int active)
 688 {
 689         struct snd_kcontrol *kctl;
 690         struct snd_kcontrol_volatile *vd;
 691         unsigned int index_offset;
 692         int ret;
 693
 694         down_write(&card->controls_rwsem);
 695         kctl = snd_ctl_find_id(card, id);
 696         if (kctl == NULL) {
 697                 ret = -ENOENT;
 698                 goto unlock;
 699         }
 700         index_offset = snd_ctl_get_ioff(kctl, id);
 701         vd = &kctl->vd[index_offset];
 702         ret = 0;
 703         if (active) {
 704                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 705                         goto unlock;
 706                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 707         } else {
 708                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 709                         goto unlock;
 710                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 711         }
 712         snd_ctl_build_ioff(id, kctl, index_offset);
 713         downgrade_write(&card->controls_rwsem);
 714         snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
 715         up_read(&card->controls_rwsem);
 716         return 1;
 717
 718  unlock:
 719         up_write(&card->controls_rwsem);
 720         return ret;
 721 }
 722 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 723
 724 /**
 725  * snd_ctl_rename_id - replace the id of a control on the card
 726  * @card: the card instance
 727  * @src_id: the old id
 728  * @dst_id: the new id
 729  *
 730  * Finds the control with the old id from the card, and replaces the
 731  * id with the new one.
 732  *
 733  * Return: Zero if successful, or a negative error code on failure.
 734  */
 735 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 736                       struct snd_ctl_elem_id *dst_id)
 737 {
 738         struct snd_kcontrol *kctl;
 739
 740         down_write(&card->controls_rwsem);
 741         kctl = snd_ctl_find_id(card, src_id);
 742         if (kctl == NULL) {
 743                 up_write(&card->controls_rwsem);
 744                 return -ENOENT;
 745         }
 746         remove_hash_entries(card, kctl);
 747         kctl->id = *dst_id;
 748         kctl->id.numid = card->last_numid + 1;
 749         card->last_numid += kctl->count;
 750         add_hash_entries(card, kctl);
 751         up_write(&card->controls_rwsem);
 752         return 0;
 753 }
 754 EXPORT_SYMBOL(snd_ctl_rename_id);
 755
 756 /**
 757  * snd_ctl_rename - rename the control on the card
 758  * @card: the card instance
 759  * @kctl: the control to rename
 760  * @name: the new name
 761  *
 762  * Renames the specified control on the card to the new name.
 763  *
 764  * Make sure to take the control write lock - down_write(&card->controls_rwsem).
 765  */
 766 void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
 767                     const char *name)
 768 {
 769         remove_hash_entries(card, kctl);
 770
 771         if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)
 772                 pr_warn("ALSA: Renamed control new name '%s' truncated to '%s'\n",
 773                         name, kctl->id.name);
 774
 775         add_hash_entries(card, kctl);
 776 }
 777 EXPORT_SYMBOL(snd_ctl_rename);
 778
 779 #ifndef CONFIG_SND_CTL_FAST_LOOKUP
 780 static struct snd_kcontrol *
 781 snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
 782 {
 783         struct snd_kcontrol *kctl;
 784
 785         list_for_each_entry(kctl, &card->controls, list) {
 786                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 787                         return kctl;
 788         }
 789         return NULL;
 790 }
 791 #endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
 792
 793 /**
 794  * snd_ctl_find_numid - find the control instance with the given number-id
 795  * @card: the card instance
 796  * @numid: the number-id to search
 797  *
 798  * Finds the control instance with the given number-id from the card.
 799  *
 800  * The caller must down card->controls_rwsem before calling this function
 801  * (if the race condition can happen).
 802  *
 803  * Return: The pointer of the instance if found, or %NULL if not.
 804  *
 805  */
 806 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 807 {
 808         if (snd_BUG_ON(!card || !numid))
 809                 return NULL;
 810 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 811         return xa_load(&card->ctl_numids, numid);
 812 #else
 813         return snd_ctl_find_numid_slow(card, numid);
 814 #endif
 815 }
 816 EXPORT_SYMBOL(snd_ctl_find_numid);
 817
 818 /**
 819  * snd_ctl_find_id - find the control instance with the given id
 820  * @card: the card instance
 821  * @id: the id to search
 822  *
 823  * Finds the control instance with the given id from the card.
 824  *
 825  * The caller must down card->controls_rwsem before calling this function
 826  * (if the race condition can happen).
 827  *
 828  * Return: The pointer of the instance if found, or %NULL if not.
 829  *
 830  */
 831 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 832                                      struct snd_ctl_elem_id *id)
 833 {
 834         struct snd_kcontrol *kctl;
 835
 836         if (snd_BUG_ON(!card || !id))
 837                 return NULL;
 838         if (id->numid != 0)
 839                 return snd_ctl_find_numid(card, id->numid);
 840 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 841         kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
 842         if (kctl && elem_id_matches(kctl, id))
 843                 return kctl;
 844         if (!card->ctl_hash_collision)
 845                 return NULL; /* we can rely on only hash table */
 846 #endif
 847         /* no matching in hash table - try all as the last resort */
 848         list_for_each_entry(kctl, &card->controls, list)
 849                 if (elem_id_matches(kctl, id))
 850                         return kctl;
 851
 852         return NULL;
 853 }
 854 EXPORT_SYMBOL(snd_ctl_find_id);
 855
 856 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 857                              unsigned int cmd, void __user *arg)
 858 {
 859         struct snd_ctl_card_info *info;
 860
 861         info = kzalloc(sizeof(*info), GFP_KERNEL);
 862         if (! info)
 863                 return -ENOMEM;
 864         down_read(&snd_ioctl_rwsem);
 865         info->card = card->number;
 866         strscpy(info->id, card->id, sizeof(info->id));
 867         strscpy(info->driver, card->driver, sizeof(info->driver));
 868         strscpy(info->name, card->shortname, sizeof(info->name));
 869         strscpy(info->longname, card->longname, sizeof(info->longname));
 870         strscpy(info->mixername, card->mixername, sizeof(info->mixername));
 871         strscpy(info->components, card->components, sizeof(info->components));
 872         up_read(&snd_ioctl_rwsem);
 873         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 874                 kfree(info);
 875                 return -EFAULT;
 876         }
 877         kfree(info);
 878         return 0;
 879 }
 880
 881 static int snd_ctl_elem_list(struct snd_card *card,
 882                              struct snd_ctl_elem_list *list)
 883 {
 884         struct snd_kcontrol *kctl;
 885         struct snd_ctl_elem_id id;
 886         unsigned int offset, space, jidx;
 887         int err = 0;
 888
 889         offset = list->offset;
 890         space = list->space;
 891
 892         down_read(&card->controls_rwsem);
 893         list->count = card->controls_count;
 894         list->used = 0;
 895         if (space > 0) {
 896                 list_for_each_entry(kctl, &card->controls, list) {
 897                         if (offset >= kctl->count) {
 898                                 offset -= kctl->count;
 899                                 continue;
 900                         }
 901                         for (jidx = offset; jidx < kctl->count; jidx++) {
 902                                 snd_ctl_build_ioff(&id, kctl, jidx);
 903                                 if (copy_to_user(list->pids + list->used, &id,
 904                                                  sizeof(id))) {
 905                                         err = -EFAULT;
 906                                         goto out;
 907                                 }
 908                                 list->used++;
 909                                 if (!--space)
 910                                         goto out;
 911                         }
 912                         offset = 0;
 913                 }
 914         }
 915  out:
 916         up_read(&card->controls_rwsem);
 917         return err;
 918 }
 919
 920 static int snd_ctl_elem_list_user(struct snd_card *card,
 921                                   struct snd_ctl_elem_list __user *_list)
 922 {
 923         struct snd_ctl_elem_list list;
 924         int err;
 925
 926         if (copy_from_user(&list, _list, sizeof(list)))
 927                 return -EFAULT;
 928         err = snd_ctl_elem_list(card, &list);
 929         if (err)
 930                 return err;
 931         if (copy_to_user(_list, &list, sizeof(list)))
 932                 return -EFAULT;
 933
 934         return 0;
 935 }
 936
 937 /* Check whether the given kctl info is valid */
 938 static int snd_ctl_check_elem_info(struct snd_card *card,
 939                                    const struct snd_ctl_elem_info *info)
 940 {
 941         static const unsigned int max_value_counts[] = {
 942                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
 943                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
 944                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
 945                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
 946                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
 947                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
 948         };
 949
 950         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
 951             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
 952                 if (card)
 953                         dev_err(card->dev,
 954                                 "control %i:%i:%i:%s:%i: invalid type %d\n",
 955                                 info->id.iface, info->id.device,
 956                                 info->id.subdevice, info->id.name,
 957                                 info->id.index, info->type);
 958                 return -EINVAL;
 959         }
 960         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
 961             info->value.enumerated.items == 0) {
 962                 if (card)
 963                         dev_err(card->dev,
 964                                 "control %i:%i:%i:%s:%i: zero enum items\n",
 965                                 info->id.iface, info->id.device,
 966                                 info->id.subdevice, info->id.name,
 967                                 info->id.index);
 968                 return -EINVAL;
 969         }
 970         if (info->count > max_value_counts[info->type]) {
 971                 if (card)
 972                         dev_err(card->dev,
 973                                 "control %i:%i:%i:%s:%i: invalid count %d\n",
 974                                 info->id.iface, info->id.device,
 975                                 info->id.subdevice, info->id.name,
 976                                 info->id.index, info->count);
 977                 return -EINVAL;
 978         }
 979
 980         return 0;
 981 }
 982
 983 /* The capacity of struct snd_ctl_elem_value.value.*/
 984 static const unsigned int value_sizes[] = {
 985         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
 986         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
 987         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
 988         [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
 989         [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
 990         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
 991 };
 992
 993 /* fill the remaining snd_ctl_elem_value data with the given pattern */
 994 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 995                                       struct snd_ctl_elem_info *info,
 996                                       u32 pattern)
 997 {
 998         size_t offset = value_sizes[info->type] * info->count;
 999
1000         offset = DIV_ROUND_UP(offset, sizeof(u32));
1001         memset32((u32 *)control->value.bytes.data + offset, pattern,
1002                  sizeof(control->value) / sizeof(u32) - offset);
1003 }
1004
1005 /* check whether the given integer ctl value is valid */
1006 static int sanity_check_int_value(struct snd_card *card,
1007                                   const struct snd_ctl_elem_value *control,
1008                                   const struct snd_ctl_elem_info *info,
1009                                   int i, bool print_error)
1010 {
1011         long long lval, lmin, lmax, lstep;
1012         u64 rem;
1013
1014         switch (info->type) {
1015         default:
1016         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1017                 lval = control->value.integer.value[i];
1018                 lmin = 0;
1019                 lmax = 1;
1020                 lstep = 0;
1021                 break;
1022         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1023                 lval = control->value.integer.value[i];
1024                 lmin = info->value.integer.min;
1025                 lmax = info->value.integer.max;
1026                 lstep = info->value.integer.step;
1027                 break;
1028         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1029                 lval = control->value.integer64.value[i];
1030                 lmin = info->value.integer64.min;
1031                 lmax = info->value.integer64.max;
1032                 lstep = info->value.integer64.step;
1033                 break;
1034         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1035                 lval = control->value.enumerated.item[i];
1036                 lmin = 0;
1037                 lmax = info->value.enumerated.items - 1;
1038                 lstep = 0;
1039                 break;
1040         }
1041
1042         if (lval < lmin || lval > lmax) {
1043                 if (print_error)
1044                         dev_err(card->dev,
1045                                 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
1046                                 control->id.iface, control->id.device,
1047                                 control->id.subdevice, control->id.name,
1048                                 control->id.index, lval, lmin, lmax, i);
1049                 return -EINVAL;
1050         }
1051         if (lstep) {
1052                 div64_u64_rem(lval, lstep, &rem);
1053                 if (rem) {
1054                         if (print_error)
1055                                 dev_err(card->dev,
1056                                         "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
1057                                         control->id.iface, control->id.device,
1058                                         control->id.subdevice, control->id.name,
1059                                         control->id.index, lval, lstep, i);
1060                         return -EINVAL;
1061                 }
1062         }
1063
1064         return 0;
1065 }
1066
1067 /* check whether the all input values are valid for the given elem value */
1068 static int sanity_check_input_values(struct snd_card *card,
1069                                      const struct snd_ctl_elem_value *control,
1070                                      const struct snd_ctl_elem_info *info,
1071                                      bool print_error)
1072 {
1073         int i, ret;
1074
1075         switch (info->type) {
1076         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1077         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1078         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1079         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1080                 for (i = 0; i < info->count; i++) {
1081                         ret = sanity_check_int_value(card, control, info, i,
1082                                                      print_error);
1083                         if (ret < 0)
1084                                 return ret;
1085                 }
1086                 break;
1087         default:
1088                 break;
1089         }
1090
1091         return 0;
1092 }
1093
1094 /* perform sanity checks to the given snd_ctl_elem_value object */
1095 static int sanity_check_elem_value(struct snd_card *card,
1096                                    const struct snd_ctl_elem_value *control,
1097                                    const struct snd_ctl_elem_info *info,
1098                                    u32 pattern)
1099 {
1100         size_t offset;
1101         int ret;
1102         u32 *p;
1103
1104         ret = sanity_check_input_values(card, control, info, true);
1105         if (ret < 0)
1106                 return ret;
1107
1108         /* check whether the remaining area kept untouched */
1109         offset = value_sizes[info->type] * info->count;
1110         offset = DIV_ROUND_UP(offset, sizeof(u32));
1111         p = (u32 *)control->value.bytes.data + offset;
1112         for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
1113                 if (*p != pattern) {
1114                         ret = -EINVAL;
1115                         break;
1116                 }
1117                 *p = 0; /* clear the checked area */
1118         }
1119
1120         return ret;
1121 }
1122
1123 static int __snd_ctl_elem_info(struct snd_card *card,
1124                                struct snd_kcontrol *kctl,
1125                                struct snd_ctl_elem_info *info,
1126                                struct snd_ctl_file *ctl)
1127 {
1128         struct snd_kcontrol_volatile *vd;
1129         unsigned int index_offset;
1130         int result;
1131
1132 #ifdef CONFIG_SND_DEBUG
1133         info->access = 0;
1134 #endif
1135         result = snd_power_ref_and_wait(card);
1136         if (!result)
1137                 result = kctl->info(kctl, info);
1138         snd_power_unref(card);
1139         if (result >= 0) {
1140                 snd_BUG_ON(info->access);
1141                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
1142                 vd = &kctl->vd[index_offset];
1143                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
1144                 info->access = vd->access;
1145                 if (vd->owner) {
1146                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
1147                         if (vd->owner == ctl)
1148                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
1149                         info->owner = pid_vnr(vd->owner->pid);
1150                 } else {
1151                         info->owner = -1;
1152                 }
1153                 if (!snd_ctl_skip_validation(info) &&
1154                     snd_ctl_check_elem_info(card, info) < 0)
1155                         result = -EINVAL;
1156         }
1157         return result;
1158 }
1159
1160 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
1161                              struct snd_ctl_elem_info *info)
1162 {
1163         struct snd_card *card = ctl->card;
1164         struct snd_kcontrol *kctl;
1165         int result;
1166
1167         down_read(&card->controls_rwsem);
1168         kctl = snd_ctl_find_id(card, &info->id);
1169         if (kctl == NULL)
1170                 result = -ENOENT;
1171         else
1172                 result = __snd_ctl_elem_info(card, kctl, info, ctl);
1173         up_read(&card->controls_rwsem);
1174         return result;
1175 }
1176
1177 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1178                                   struct snd_ctl_elem_info __user *_info)
1179 {
1180         struct snd_ctl_elem_info info;
1181         int result;
1182
1183         if (copy_from_user(&info, _info, sizeof(info)))
1184                 return -EFAULT;
1185         result = snd_ctl_elem_info(ctl, &info);
1186         if (result < 0)
1187                 return result;
1188         /* drop internal access flags */
1189         info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
1190                          SNDRV_CTL_ELEM_ACCESS_LED_MASK);
1191         if (copy_to_user(_info, &info, sizeof(info)))
1192                 return -EFAULT;
1193         return result;
1194 }
1195
1196 static int snd_ctl_elem_read(struct snd_card *card,
1197                              struct snd_ctl_elem_value *control)
1198 {
1199         struct snd_kcontrol *kctl;
1200         struct snd_kcontrol_volatile *vd;
1201         unsigned int index_offset;
1202         struct snd_ctl_elem_info info;
1203         const u32 pattern = 0xdeadbeef;
1204         int ret;
1205
1206         kctl = snd_ctl_find_id(card, &control->id);
1207         if (kctl == NULL)
1208                 return -ENOENT;
1209
1210         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1211         vd = &kctl->vd[index_offset];
1212         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1213                 return -EPERM;
1214
1215         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1216
1217 #ifdef CONFIG_SND_CTL_DEBUG
1218         /* info is needed only for validation */
1219         memset(&info, 0, sizeof(info));
1220         info.id = control->id;
1221         ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1222         if (ret < 0)
1223                 return ret;
1224 #endif
1225
1226         if (!snd_ctl_skip_validation(&info))
1227                 fill_remaining_elem_value(control, &info, pattern);
1228         ret = snd_power_ref_and_wait(card);
1229         if (!ret)
1230                 ret = kctl->get(kctl, control);
1231         snd_power_unref(card);
1232         if (ret < 0)
1233                 return ret;
1234         if (!snd_ctl_skip_validation(&info) &&
1235             sanity_check_elem_value(card, control, &info, pattern) < 0) {
1236                 dev_err(card->dev,
1237                         "control %i:%i:%i:%s:%i: access overflow\n",
1238                         control->id.iface, control->id.device,
1239                         control->id.subdevice, control->id.name,
1240                         control->id.index);
1241                 return -EINVAL;
1242         }
1243         return ret;
1244 }
1245
1246 static int snd_ctl_elem_read_user(struct snd_card *card,
1247                                   struct snd_ctl_elem_value __user *_control)
1248 {
1249         struct snd_ctl_elem_value *control;
1250         int result;
1251
1252         control = memdup_user(_control, sizeof(*control));
1253         if (IS_ERR(control))
1254                 return PTR_ERR(control);
1255
1256         down_read(&card->controls_rwsem);
1257         result = snd_ctl_elem_read(card, control);
1258         up_read(&card->controls_rwsem);
1259         if (result < 0)
1260                 goto error;
1261
1262         if (copy_to_user(_control, control, sizeof(*control)))
1263                 result = -EFAULT;
1264  error:
1265         kfree(control);
1266         return result;
1267 }
1268
1269 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1270                               struct snd_ctl_elem_value *control)
1271 {
1272         struct snd_kcontrol *kctl;
1273         struct snd_kcontrol_volatile *vd;
1274         unsigned int index_offset;
1275         int result;
1276
1277         down_write(&card->controls_rwsem);
1278         kctl = snd_ctl_find_id(card, &control->id);
1279         if (kctl == NULL) {
1280                 up_write(&card->controls_rwsem);
1281                 return -ENOENT;
1282         }
1283
1284         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1285         vd = &kctl->vd[index_offset];
1286         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1287             (file && vd->owner && vd->owner != file)) {
1288                 up_write(&card->controls_rwsem);
1289                 return -EPERM;
1290         }
1291
1292         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1293         result = snd_power_ref_and_wait(card);
1294         /* validate input values */
1295         if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION) && !result) {
1296                 struct snd_ctl_elem_info info;
1297
1298                 memset(&info, 0, sizeof(info));
1299                 info.id = control->id;
1300                 result = __snd_ctl_elem_info(card, kctl, &info, NULL);
1301                 if (!result)
1302                         result = sanity_check_input_values(card, control, &info,
1303                                                            false);
1304         }
1305         if (!result)
1306                 result = kctl->put(kctl, control);
1307         snd_power_unref(card);
1308         if (result < 0) {
1309                 up_write(&card->controls_rwsem);
1310                 return result;
1311         }
1312
1313         if (result > 0) {
1314                 downgrade_write(&card->controls_rwsem);
1315                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
1316                 up_read(&card->controls_rwsem);
1317         } else {
1318                 up_write(&card->controls_rwsem);
1319         }
1320
1321         return 0;
1322 }
1323
1324 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1325                                    struct snd_ctl_elem_value __user *_control)
1326 {
1327         struct snd_ctl_elem_value *control;
1328         struct snd_card *card;
1329         int result;
1330
1331         control = memdup_user(_control, sizeof(*control));
1332         if (IS_ERR(control))
1333                 return PTR_ERR(control);
1334
1335         card = file->card;
1336         result = snd_ctl_elem_write(card, file, control);
1337         if (result < 0)
1338                 goto error;
1339
1340         if (copy_to_user(_control, control, sizeof(*control)))
1341                 result = -EFAULT;
1342  error:
1343         kfree(control);
1344         return result;
1345 }
1346
1347 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1348                              struct snd_ctl_elem_id __user *_id)
1349 {
1350         struct snd_card *card = file->card;
1351         struct snd_ctl_elem_id id;
1352         struct snd_kcontrol *kctl;
1353         struct snd_kcontrol_volatile *vd;
1354         int result;
1355
1356         if (copy_from_user(&id, _id, sizeof(id)))
1357                 return -EFAULT;
1358         down_write(&card->controls_rwsem);
1359         kctl = snd_ctl_find_id(card, &id);
1360         if (kctl == NULL) {
1361                 result = -ENOENT;
1362         } else {
1363                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1364                 if (vd->owner != NULL)
1365                         result = -EBUSY;
1366                 else {
1367                         vd->owner = file;
1368                         result = 0;
1369                 }
1370         }
1371         up_write(&card->controls_rwsem);
1372         return result;
1373 }
1374
1375 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1376                                struct snd_ctl_elem_id __user *_id)
1377 {
1378         struct snd_card *card = file->card;
1379         struct snd_ctl_elem_id id;
1380         struct snd_kcontrol *kctl;
1381         struct snd_kcontrol_volatile *vd;
1382         int result;
1383
1384         if (copy_from_user(&id, _id, sizeof(id)))
1385                 return -EFAULT;
1386         down_write(&card->controls_rwsem);
1387         kctl = snd_ctl_find_id(card, &id);
1388         if (kctl == NULL) {
1389                 result = -ENOENT;
1390         } else {
1391                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1392                 if (vd->owner == NULL)
1393                         result = -EINVAL;
1394                 else if (vd->owner != file)
1395                         result = -EPERM;
1396                 else {
1397                         vd->owner = NULL;
1398                         result = 0;
1399                 }
1400         }
1401         up_write(&card->controls_rwsem);
1402         return result;
1403 }
1404
1405 struct user_element {
1406         struct snd_ctl_elem_info info;
1407         struct snd_card *card;
1408         char *elem_data;                /* element data */
1409         unsigned long elem_data_size;   /* size of element data in bytes */
1410         void *tlv_data;                 /* TLV data */
1411         unsigned long tlv_data_size;    /* TLV data size */
1412         void *priv_data;                /* private data (like strings for enumerated type) */
1413 };
1414
1415 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1416 static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
1417 {
1418         return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
1419 }
1420
1421 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1422                                   struct snd_ctl_elem_info *uinfo)
1423 {
1424         struct user_element *ue = kcontrol->private_data;
1425         unsigned int offset;
1426
1427         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1428         *uinfo = ue->info;
1429         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1430
1431         return 0;
1432 }
1433
1434 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1435                                        struct snd_ctl_elem_info *uinfo)
1436 {
1437         struct user_element *ue = kcontrol->private_data;
1438         const char *names;
1439         unsigned int item;
1440         unsigned int offset;
1441
1442         item = uinfo->value.enumerated.item;
1443
1444         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1445         *uinfo = ue->info;
1446         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1447
1448         item = min(item, uinfo->value.enumerated.items - 1);
1449         uinfo->value.enumerated.item = item;
1450
1451         names = ue->priv_data;
1452         for (; item > 0; --item)
1453                 names += strlen(names) + 1;
1454         strcpy(uinfo->value.enumerated.name, names);
1455
1456         return 0;
1457 }
1458
1459 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1460                                  struct snd_ctl_elem_value *ucontrol)
1461 {
1462         struct user_element *ue = kcontrol->private_data;
1463         unsigned int size = ue->elem_data_size;
1464         char *src = ue->elem_data +
1465                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1466
1467         memcpy(&ucontrol->value, src, size);
1468         return 0;
1469 }
1470
1471 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1472                                  struct snd_ctl_elem_value *ucontrol)
1473 {
1474         int change;
1475         struct user_element *ue = kcontrol->private_data;
1476         unsigned int size = ue->elem_data_size;
1477         char *dst = ue->elem_data +
1478                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1479
1480         change = memcmp(&ucontrol->value, dst, size) != 0;
1481         if (change)
1482                 memcpy(dst, &ucontrol->value, size);
1483         return change;
1484 }
1485
1486 /* called in controls_rwsem write lock */
1487 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1488                             unsigned int size)
1489 {
1490         struct user_element *ue = kctl->private_data;
1491         unsigned int *container;
1492         unsigned int mask = 0;
1493         int i;
1494         int change;
1495
1496         if (size > 1024 * 128)  /* sane value */
1497                 return -EINVAL;
1498
1499         // does the TLV size change cause overflow?
1500         if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
1501                 return -ENOMEM;
1502
1503         container = vmemdup_user(buf, size);
1504         if (IS_ERR(container))
1505                 return PTR_ERR(container);
1506
1507         change = ue->tlv_data_size != size;
1508         if (!change)
1509                 change = memcmp(ue->tlv_data, container, size) != 0;
1510         if (!change) {
1511                 kvfree(container);
1512                 return 0;
1513         }
1514
1515         if (ue->tlv_data == NULL) {
1516                 /* Now TLV data is available. */
1517                 for (i = 0; i < kctl->count; ++i)
1518                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1519                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1520         } else {
1521                 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1522                 ue->tlv_data_size = 0;
1523                 kvfree(ue->tlv_data);
1524         }
1525
1526         ue->tlv_data = container;
1527         ue->tlv_data_size = size;
1528         // decremented at private_free.
1529         ue->card->user_ctl_alloc_size += size;
1530
1531         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1532         for (i = 0; i < kctl->count; ++i)
1533                 snd_ctl_notify_one(ue->card, mask, kctl, i);
1534
1535         return change;
1536 }
1537
1538 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1539                          unsigned int size)
1540 {
1541         struct user_element *ue = kctl->private_data;
1542
1543         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1544                 return -ENXIO;
1545
1546         if (size < ue->tlv_data_size)
1547                 return -ENOSPC;
1548
1549         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1550                 return -EFAULT;
1551
1552         return 0;
1553 }
1554
1555 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1556                                  unsigned int size, unsigned int __user *buf)
1557 {
1558         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1559                 return replace_user_tlv(kctl, buf, size);
1560         else
1561                 return read_user_tlv(kctl, buf, size);
1562 }
1563
1564 /* called in controls_rwsem write lock */
1565 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1566 {
1567         char *names, *p;
1568         size_t buf_len, name_len;
1569         unsigned int i;
1570         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1571
1572         buf_len = ue->info.value.enumerated.names_length;
1573         if (buf_len > 64 * 1024)
1574                 return -EINVAL;
1575
1576         if (check_user_elem_overflow(ue->card, buf_len))
1577                 return -ENOMEM;
1578         names = vmemdup_user((const void __user *)user_ptrval, buf_len);
1579         if (IS_ERR(names))
1580                 return PTR_ERR(names);
1581
1582         /* check that there are enough valid names */
1583         p = names;
1584         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1585                 name_len = strnlen(p, buf_len);
1586                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1587                         kvfree(names);
1588                         return -EINVAL;
1589                 }
1590                 p += name_len + 1;
1591                 buf_len -= name_len + 1;
1592         }
1593
1594         ue->priv_data = names;
1595         ue->info.value.enumerated.names_ptr = 0;
1596         // increment the allocation size; decremented again at private_free.
1597         ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
1598
1599         return 0;
1600 }
1601
1602 static size_t compute_user_elem_size(size_t size, unsigned int count)
1603 {
1604         return sizeof(struct user_element) + size * count;
1605 }
1606
1607 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1608 {
1609         struct user_element *ue = kcontrol->private_data;
1610
1611         // decrement the allocation size.
1612         ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
1613         ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1614         if (ue->priv_data)
1615                 ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
1616
1617         kvfree(ue->tlv_data);
1618         kvfree(ue->priv_data);
1619         kfree(ue);
1620 }
1621
1622 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1623                             struct snd_ctl_elem_info *info, int replace)
1624 {
1625         struct snd_card *card = file->card;
1626         struct snd_kcontrol *kctl;
1627         unsigned int count;
1628         unsigned int access;
1629         long private_size;
1630         size_t alloc_size;
1631         struct user_element *ue;
1632         unsigned int offset;
1633         int err;
1634
1635         if (!*info->id.name)
1636                 return -EINVAL;
1637         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1638                 return -EINVAL;
1639
1640         /* Delete a control to replace them if needed. */
1641         if (replace) {
1642                 info->id.numid = 0;
1643                 err = snd_ctl_remove_user_ctl(file, &info->id);
1644                 if (err)
1645                         return err;
1646         }
1647
1648         /* Check the number of elements for this userspace control. */
1649         count = info->owner;
1650         if (count == 0)
1651                 count = 1;
1652
1653         /* Arrange access permissions if needed. */
1654         access = info->access;
1655         if (access == 0)
1656                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1657         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1658                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1659                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1660
1661         /* In initial state, nothing is available as TLV container. */
1662         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1663                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1664         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1665
1666         /*
1667          * Check information and calculate the size of data specific to
1668          * this userspace control.
1669          */
1670         /* pass NULL to card for suppressing error messages */
1671         err = snd_ctl_check_elem_info(NULL, info);
1672         if (err < 0)
1673                 return err;
1674         /* user-space control doesn't allow zero-size data */
1675         if (info->count < 1)
1676                 return -EINVAL;
1677         private_size = value_sizes[info->type] * info->count;
1678         alloc_size = compute_user_elem_size(private_size, count);
1679
1680         down_write(&card->controls_rwsem);
1681         if (check_user_elem_overflow(card, alloc_size)) {
1682                 err = -ENOMEM;
1683                 goto unlock;
1684         }
1685
1686         /*
1687          * Keep memory object for this userspace control. After passing this
1688          * code block, the instance should be freed by snd_ctl_free_one().
1689          *
1690          * Note that these elements in this control are locked.
1691          */
1692         err = snd_ctl_new(&kctl, count, access, file);
1693         if (err < 0)
1694                 goto unlock;
1695         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1696         ue = kzalloc(alloc_size, GFP_KERNEL);
1697         if (!ue) {
1698                 kfree(kctl);
1699                 err = -ENOMEM;
1700                 goto unlock;
1701         }
1702         kctl->private_data = ue;
1703         kctl->private_free = snd_ctl_elem_user_free;
1704
1705         // increment the allocated size; decremented again at private_free.
1706         card->user_ctl_alloc_size += alloc_size;
1707
1708         /* Set private data for this userspace control. */
1709         ue->card = card;
1710         ue->info = *info;
1711         ue->info.access = 0;
1712         ue->elem_data = (char *)ue + sizeof(*ue);
1713         ue->elem_data_size = private_size;
1714         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1715                 err = snd_ctl_elem_init_enum_names(ue);
1716                 if (err < 0) {
1717                         snd_ctl_free_one(kctl);
1718                         goto unlock;
1719                 }
1720         }
1721
1722         /* Set callback functions. */
1723         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1724                 kctl->info = snd_ctl_elem_user_enum_info;
1725         else
1726                 kctl->info = snd_ctl_elem_user_info;
1727         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1728                 kctl->get = snd_ctl_elem_user_get;
1729         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1730                 kctl->put = snd_ctl_elem_user_put;
1731         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1732                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1733
1734         /* This function manage to free the instance on failure. */
1735         err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1736         if (err < 0) {
1737                 snd_ctl_free_one(kctl);
1738                 goto unlock;
1739         }
1740         offset = snd_ctl_get_ioff(kctl, &info->id);
1741         snd_ctl_build_ioff(&info->id, kctl, offset);
1742         /*
1743          * Here we cannot fill any field for the number of elements added by
1744          * this operation because there're no specific fields. The usage of
1745          * 'owner' field for this purpose may cause any bugs to userspace
1746          * applications because the field originally means PID of a process
1747          * which locks the element.
1748          */
1749  unlock:
1750         up_write(&card->controls_rwsem);
1751         return err;
1752 }
1753
1754 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1755                                  struct snd_ctl_elem_info __user *_info, int replace)
1756 {
1757         struct snd_ctl_elem_info info;
1758         int err;
1759
1760         if (copy_from_user(&info, _info, sizeof(info)))
1761                 return -EFAULT;
1762         err = snd_ctl_elem_add(file, &info, replace);
1763         if (err < 0)
1764                 return err;
1765         if (copy_to_user(_info, &info, sizeof(info))) {
1766                 snd_ctl_remove_user_ctl(file, &info.id);
1767                 return -EFAULT;
1768         }
1769
1770         return 0;
1771 }
1772
1773 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1774                                struct snd_ctl_elem_id __user *_id)
1775 {
1776         struct snd_ctl_elem_id id;
1777
1778         if (copy_from_user(&id, _id, sizeof(id)))
1779                 return -EFAULT;
1780         return snd_ctl_remove_user_ctl(file, &id);
1781 }
1782
1783 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1784 {
1785         int subscribe;
1786         if (get_user(subscribe, ptr))
1787                 return -EFAULT;
1788         if (subscribe < 0) {
1789                 subscribe = file->subscribed;
1790                 if (put_user(subscribe, ptr))
1791                         return -EFAULT;
1792                 return 0;
1793         }
1794         if (subscribe) {
1795                 file->subscribed = 1;
1796                 return 0;
1797         } else if (file->subscribed) {
1798                 snd_ctl_empty_read_queue(file);
1799                 file->subscribed = 0;
1800         }
1801         return 0;
1802 }
1803
1804 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1805                             struct snd_kcontrol *kctl,
1806                             struct snd_ctl_elem_id *id,
1807                             unsigned int __user *buf, unsigned int size)
1808 {
1809         static const struct {
1810                 int op;
1811                 int perm;
1812         } pairs[] = {
1813                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1814                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1815                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1816         };
1817         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1818         int i, ret;
1819
1820         /* Check support of the request for this element. */
1821         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1822                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1823                         break;
1824         }
1825         if (i == ARRAY_SIZE(pairs))
1826                 return -ENXIO;
1827
1828         if (kctl->tlv.c == NULL)
1829                 return -ENXIO;
1830
1831         /* Write and command operations are not allowed for locked element. */
1832         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1833             vd->owner != NULL && vd->owner != file)
1834                 return -EPERM;
1835
1836         ret = snd_power_ref_and_wait(file->card);
1837         if (!ret)
1838                 ret = kctl->tlv.c(kctl, op_flag, size, buf);
1839         snd_power_unref(file->card);
1840         return ret;
1841 }
1842
1843 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1844                         unsigned int __user *buf, unsigned int size)
1845 {
1846         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1847         unsigned int len;
1848
1849         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1850                 return -ENXIO;
1851
1852         if (kctl->tlv.p == NULL)
1853                 return -ENXIO;
1854
1855         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1856         if (size < len)
1857                 return -ENOMEM;
1858
1859         if (copy_to_user(buf, kctl->tlv.p, len))
1860                 return -EFAULT;
1861
1862         return 0;
1863 }
1864
1865 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1866                              struct snd_ctl_tlv __user *buf,
1867                              int op_flag)
1868 {
1869         struct snd_ctl_tlv header;
1870         unsigned int __user *container;
1871         unsigned int container_size;
1872         struct snd_kcontrol *kctl;
1873         struct snd_ctl_elem_id id;
1874         struct snd_kcontrol_volatile *vd;
1875
1876         if (copy_from_user(&header, buf, sizeof(header)))
1877                 return -EFAULT;
1878
1879         /* In design of control core, numerical ID starts at 1. */
1880         if (header.numid == 0)
1881                 return -EINVAL;
1882
1883         /* At least, container should include type and length fields.  */
1884         if (header.length < sizeof(unsigned int) * 2)
1885                 return -EINVAL;
1886         container_size = header.length;
1887         container = buf->tlv;
1888
1889         kctl = snd_ctl_find_numid(file->card, header.numid);
1890         if (kctl == NULL)
1891                 return -ENOENT;
1892
1893         /* Calculate index of the element in this set. */
1894         id = kctl->id;
1895         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1896         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1897
1898         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1899                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1900                                         container_size);
1901         } else {
1902                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1903                         return read_tlv_buf(kctl, &id, container,
1904                                             container_size);
1905                 }
1906         }
1907
1908         /* Not supported. */
1909         return -ENXIO;
1910 }
1911
1912 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1913 {
1914         struct snd_ctl_file *ctl;
1915         struct snd_card *card;
1916         struct snd_kctl_ioctl *p;
1917         void __user *argp = (void __user *)arg;
1918         int __user *ip = argp;
1919         int err;
1920
1921         ctl = file->private_data;
1922         card = ctl->card;
1923         if (snd_BUG_ON(!card))
1924                 return -ENXIO;
1925         switch (cmd) {
1926         case SNDRV_CTL_IOCTL_PVERSION:
1927                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1928         case SNDRV_CTL_IOCTL_CARD_INFO:
1929                 return snd_ctl_card_info(card, ctl, cmd, argp);
1930         case SNDRV_CTL_IOCTL_ELEM_LIST:
1931                 return snd_ctl_elem_list_user(card, argp);
1932         case SNDRV_CTL_IOCTL_ELEM_INFO:
1933                 return snd_ctl_elem_info_user(ctl, argp);
1934         case SNDRV_CTL_IOCTL_ELEM_READ:
1935                 return snd_ctl_elem_read_user(card, argp);
1936         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1937                 return snd_ctl_elem_write_user(ctl, argp);
1938         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1939                 return snd_ctl_elem_lock(ctl, argp);
1940         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1941                 return snd_ctl_elem_unlock(ctl, argp);
1942         case SNDRV_CTL_IOCTL_ELEM_ADD:
1943                 return snd_ctl_elem_add_user(ctl, argp, 0);
1944         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1945                 return snd_ctl_elem_add_user(ctl, argp, 1);
1946         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1947                 return snd_ctl_elem_remove(ctl, argp);
1948         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1949                 return snd_ctl_subscribe_events(ctl, ip);
1950         case SNDRV_CTL_IOCTL_TLV_READ:
1951                 down_read(&ctl->card->controls_rwsem);
1952                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1953                 up_read(&ctl->card->controls_rwsem);
1954                 return err;
1955         case SNDRV_CTL_IOCTL_TLV_WRITE:
1956                 down_write(&ctl->card->controls_rwsem);
1957                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1958                 up_write(&ctl->card->controls_rwsem);
1959                 return err;
1960         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1961                 down_write(&ctl->card->controls_rwsem);
1962                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1963                 up_write(&ctl->card->controls_rwsem);
1964                 return err;
1965         case SNDRV_CTL_IOCTL_POWER:
1966                 return -ENOPROTOOPT;
1967         case SNDRV_CTL_IOCTL_POWER_STATE:
1968                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1969         }
1970         down_read(&snd_ioctl_rwsem);
1971         list_for_each_entry(p, &snd_control_ioctls, list) {
1972                 err = p->fioctl(card, ctl, cmd, arg);
1973                 if (err != -ENOIOCTLCMD) {
1974                         up_read(&snd_ioctl_rwsem);
1975                         return err;
1976                 }
1977         }
1978         up_read(&snd_ioctl_rwsem);
1979         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1980         return -ENOTTY;
1981 }
1982
1983 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1984                             size_t count, loff_t * offset)
1985 {
1986         struct snd_ctl_file *ctl;
1987         int err = 0;
1988         ssize_t result = 0;
1989
1990         ctl = file->private_data;
1991         if (snd_BUG_ON(!ctl || !ctl->card))
1992                 return -ENXIO;
1993         if (!ctl->subscribed)
1994                 return -EBADFD;
1995         if (count < sizeof(struct snd_ctl_event))
1996                 return -EINVAL;
1997         spin_lock_irq(&ctl->read_lock);
1998         while (count >= sizeof(struct snd_ctl_event)) {
1999                 struct snd_ctl_event ev;
2000                 struct snd_kctl_event *kev;
2001                 while (list_empty(&ctl->events)) {
2002                         wait_queue_entry_t wait;
2003                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2004                                 err = -EAGAIN;
2005                                 goto __end_lock;
2006                         }
2007                         init_waitqueue_entry(&wait, current);
2008                         add_wait_queue(&ctl->change_sleep, &wait);
2009                         set_current_state(TASK_INTERRUPTIBLE);
2010                         spin_unlock_irq(&ctl->read_lock);
2011                         schedule();
2012                         remove_wait_queue(&ctl->change_sleep, &wait);
2013                         if (ctl->card->shutdown)
2014                                 return -ENODEV;
2015                         if (signal_pending(current))
2016                                 return -ERESTARTSYS;
2017                         spin_lock_irq(&ctl->read_lock);
2018                 }
2019                 kev = snd_kctl_event(ctl->events.next);
2020                 ev.type = SNDRV_CTL_EVENT_ELEM;
2021                 ev.data.elem.mask = kev->mask;
2022                 ev.data.elem.id = kev->id;
2023                 list_del(&kev->list);
2024                 spin_unlock_irq(&ctl->read_lock);
2025                 kfree(kev);
2026                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
2027                         err = -EFAULT;
2028                         goto __end;
2029                 }
2030                 spin_lock_irq(&ctl->read_lock);
2031                 buffer += sizeof(struct snd_ctl_event);
2032                 count -= sizeof(struct snd_ctl_event);
2033                 result += sizeof(struct snd_ctl_event);
2034         }
2035       __end_lock:
2036         spin_unlock_irq(&ctl->read_lock);
2037       __end:
2038         return result > 0 ? result : err;
2039 }
2040
2041 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
2042 {
2043         __poll_t mask;
2044         struct snd_ctl_file *ctl;
2045
2046         ctl = file->private_data;
2047         if (!ctl->subscribed)
2048                 return 0;
2049         poll_wait(file, &ctl->change_sleep, wait);
2050
2051         mask = 0;
2052         if (!list_empty(&ctl->events))
2053                 mask |= EPOLLIN | EPOLLRDNORM;
2054
2055         return mask;
2056 }
2057
2058 /*
2059  * register the device-specific control-ioctls.
2060  * called from each device manager like pcm.c, hwdep.c, etc.
2061  */
2062 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
2063 {
2064         struct snd_kctl_ioctl *pn;
2065
2066         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
2067         if (pn == NULL)
2068                 return -ENOMEM;
2069         pn->fioctl = fcn;
2070         down_write(&snd_ioctl_rwsem);
2071         list_add_tail(&pn->list, lists);
2072         up_write(&snd_ioctl_rwsem);
2073         return 0;
2074 }
2075
2076 /**
2077  * snd_ctl_register_ioctl - register the device-specific control-ioctls
2078  * @fcn: ioctl callback function
2079  *
2080  * called from each device manager like pcm.c, hwdep.c, etc.
2081  *
2082  * Return: zero if successful, or a negative error code
2083  */
2084 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
2085 {
2086         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
2087 }
2088 EXPORT_SYMBOL(snd_ctl_register_ioctl);
2089
2090 #ifdef CONFIG_COMPAT
2091 /**
2092  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
2093  * control-ioctls
2094  * @fcn: ioctl callback function
2095  *
2096  * Return: zero if successful, or a negative error code
2097  */
2098 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2099 {
2100         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
2101 }
2102 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
2103 #endif
2104
2105 /*
2106  * de-register the device-specific control-ioctls.
2107  */
2108 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
2109                                      struct list_head *lists)
2110 {
2111         struct snd_kctl_ioctl *p;
2112
2113         if (snd_BUG_ON(!fcn))
2114                 return -EINVAL;
2115         down_write(&snd_ioctl_rwsem);
2116         list_for_each_entry(p, lists, list) {
2117                 if (p->fioctl == fcn) {
2118                         list_del(&p->list);
2119                         up_write(&snd_ioctl_rwsem);
2120                         kfree(p);
2121                         return 0;
2122                 }
2123         }
2124         up_write(&snd_ioctl_rwsem);
2125         snd_BUG();
2126         return -EINVAL;
2127 }
2128
2129 /**
2130  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
2131  * @fcn: ioctl callback function to unregister
2132  *
2133  * Return: zero if successful, or a negative error code
2134  */
2135 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
2136 {
2137         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
2138 }
2139 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
2140
2141 #ifdef CONFIG_COMPAT
2142 /**
2143  * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
2144  * 32bit control-ioctls
2145  * @fcn: ioctl callback function to unregister
2146  *
2147  * Return: zero if successful, or a negative error code
2148  */
2149 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2150 {
2151         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
2152 }
2153 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
2154 #endif
2155
2156 static int snd_ctl_fasync(int fd, struct file * file, int on)
2157 {
2158         struct snd_ctl_file *ctl;
2159
2160         ctl = file->private_data;
2161         return snd_fasync_helper(fd, file, on, &ctl->fasync);
2162 }
2163
2164 /* return the preferred subdevice number if already assigned;
2165  * otherwise return -1
2166  */
2167 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
2168 {
2169         struct snd_ctl_file *kctl;
2170         int subdevice = -1;
2171         unsigned long flags;
2172
2173         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2174         list_for_each_entry(kctl, &card->ctl_files, list) {
2175                 if (kctl->pid == task_pid(current)) {
2176                         subdevice = kctl->preferred_subdevice[type];
2177                         if (subdevice != -1)
2178                                 break;
2179                 }
2180         }
2181         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2182         return subdevice;
2183 }
2184 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
2185
2186 /*
2187  * ioctl32 compat
2188  */
2189 #ifdef CONFIG_COMPAT
2190 #include "control_compat.c"
2191 #else
2192 #define snd_ctl_ioctl_compat    NULL
2193 #endif
2194
2195 /*
2196  * control layers (audio LED etc.)
2197  */
2198
2199 /**
2200  * snd_ctl_request_layer - request to use the layer
2201  * @module_name: Name of the kernel module (NULL == build-in)
2202  *
2203  * Return: zero if successful, or an error code when the module cannot be loaded
2204  */
2205 int snd_ctl_request_layer(const char *module_name)
2206 {
2207         struct snd_ctl_layer_ops *lops;
2208
2209         if (module_name == NULL)
2210                 return 0;
2211         down_read(&snd_ctl_layer_rwsem);
2212         for (lops = snd_ctl_layer; lops; lops = lops->next)
2213                 if (strcmp(lops->module_name, module_name) == 0)
2214                         break;
2215         up_read(&snd_ctl_layer_rwsem);
2216         if (lops)
2217                 return 0;
2218         return request_module(module_name);
2219 }
2220 EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
2221
2222 /**
2223  * snd_ctl_register_layer - register new control layer
2224  * @lops: operation structure
2225  *
2226  * The new layer can track all control elements and do additional
2227  * operations on top (like audio LED handling).
2228  */
2229 void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
2230 {
2231         struct snd_card *card;
2232         int card_number;
2233
2234         down_write(&snd_ctl_layer_rwsem);
2235         lops->next = snd_ctl_layer;
2236         snd_ctl_layer = lops;
2237         up_write(&snd_ctl_layer_rwsem);
2238         for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
2239                 card = snd_card_ref(card_number);
2240                 if (card) {
2241                         down_read(&card->controls_rwsem);
2242                         lops->lregister(card);
2243                         up_read(&card->controls_rwsem);
2244                         snd_card_unref(card);
2245                 }
2246         }
2247 }
2248 EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
2249
2250 /**
2251  * snd_ctl_disconnect_layer - disconnect control layer
2252  * @lops: operation structure
2253  *
2254  * It is expected that the information about tracked cards
2255  * is freed before this call (the disconnect callback is
2256  * not called here).
2257  */
2258 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
2259 {
2260         struct snd_ctl_layer_ops *lops2, *prev_lops2;
2261
2262         down_write(&snd_ctl_layer_rwsem);
2263         for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
2264                 if (lops2 == lops) {
2265                         if (!prev_lops2)
2266                                 snd_ctl_layer = lops->next;
2267                         else
2268                                 prev_lops2->next = lops->next;
2269                         break;
2270                 }
2271                 prev_lops2 = lops2;
2272         }
2273         up_write(&snd_ctl_layer_rwsem);
2274 }
2275 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
2276
2277 /*
2278  *  INIT PART
2279  */
2280
2281 static const struct file_operations snd_ctl_f_ops =
2282 {
2283         .owner =        THIS_MODULE,
2284         .read =         snd_ctl_read,
2285         .open =         snd_ctl_open,
2286         .release =      snd_ctl_release,
2287         .llseek =       no_llseek,
2288         .poll =         snd_ctl_poll,
2289         .unlocked_ioctl =       snd_ctl_ioctl,
2290         .compat_ioctl = snd_ctl_ioctl_compat,
2291         .fasync =       snd_ctl_fasync,
2292 };
2293
2294 /*
2295  * registration of the control device
2296  */
2297 static int snd_ctl_dev_register(struct snd_device *device)
2298 {
2299         struct snd_card *card = device->device_data;
2300         struct snd_ctl_layer_ops *lops;
2301         int err;
2302
2303         err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2304                                   &snd_ctl_f_ops, card, &card->ctl_dev);
2305         if (err < 0)
2306                 return err;
2307         down_read(&card->controls_rwsem);
2308         down_read(&snd_ctl_layer_rwsem);
2309         for (lops = snd_ctl_layer; lops; lops = lops->next)
2310                 lops->lregister(card);
2311         up_read(&snd_ctl_layer_rwsem);
2312         up_read(&card->controls_rwsem);
2313         return 0;
2314 }
2315
2316 /*
2317  * disconnection of the control device
2318  */
2319 static int snd_ctl_dev_disconnect(struct snd_device *device)
2320 {
2321         struct snd_card *card = device->device_data;
2322         struct snd_ctl_file *ctl;
2323         struct snd_ctl_layer_ops *lops;
2324         unsigned long flags;
2325
2326         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2327         list_for_each_entry(ctl, &card->ctl_files, list) {
2328                 wake_up(&ctl->change_sleep);
2329                 snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
2330         }
2331         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2332
2333         down_read(&card->controls_rwsem);
2334         down_read(&snd_ctl_layer_rwsem);
2335         for (lops = snd_ctl_layer; lops; lops = lops->next)
2336                 lops->ldisconnect(card);
2337         up_read(&snd_ctl_layer_rwsem);
2338         up_read(&card->controls_rwsem);
2339
2340         return snd_unregister_device(&card->ctl_dev);
2341 }
2342
2343 /*
2344  * free all controls
2345  */
2346 static int snd_ctl_dev_free(struct snd_device *device)
2347 {
2348         struct snd_card *card = device->device_data;
2349         struct snd_kcontrol *control;
2350
2351         down_write(&card->controls_rwsem);
2352         while (!list_empty(&card->controls)) {
2353                 control = snd_kcontrol(card->controls.next);
2354                 __snd_ctl_remove(card, control, false);
2355         }
2356
2357 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
2358         xa_destroy(&card->ctl_numids);
2359         xa_destroy(&card->ctl_hash);
2360 #endif
2361         up_write(&card->controls_rwsem);
2362         put_device(&card->ctl_dev);
2363         return 0;
2364 }
2365
2366 /*
2367  * create control core:
2368  * called from init.c
2369  */
2370 int snd_ctl_create(struct snd_card *card)
2371 {
2372         static const struct snd_device_ops ops = {
2373                 .dev_free = snd_ctl_dev_free,
2374                 .dev_register = snd_ctl_dev_register,
2375                 .dev_disconnect = snd_ctl_dev_disconnect,
2376         };
2377         int err;
2378
2379         if (snd_BUG_ON(!card))
2380                 return -ENXIO;
2381         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2382                 return -ENXIO;
2383
2384         snd_device_initialize(&card->ctl_dev, card);
2385         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2386
2387         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2388         if (err < 0)
2389                 put_device(&card->ctl_dev);
2390         return err;
2391 }
2392
2393 /*
2394  * Frequently used control callbacks/helpers
2395  */
2396
2397 /**
2398  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2399  * callback with a mono channel
2400  * @kcontrol: the kcontrol instance
2401  * @uinfo: info to store
2402  *
2403  * This is a function that can be used as info callback for a standard
2404  * boolean control with a single mono channel.
2405  *
2406  * Return: Zero (always successful)
2407  */
2408 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2409                               struct snd_ctl_elem_info *uinfo)
2410 {
2411         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2412         uinfo->count = 1;
2413         uinfo->value.integer.min = 0;
2414         uinfo->value.integer.max = 1;
2415         return 0;
2416 }
2417 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2418
2419 /**
2420  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2421  * callback with stereo two channels
2422  * @kcontrol: the kcontrol instance
2423  * @uinfo: info to store
2424  *
2425  * This is a function that can be used as info callback for a standard
2426  * boolean control with stereo two channels.
2427  *
2428  * Return: Zero (always successful)
2429  */
2430 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2431                                 struct snd_ctl_elem_info *uinfo)
2432 {
2433         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2434         uinfo->count = 2;
2435         uinfo->value.integer.min = 0;
2436         uinfo->value.integer.max = 1;
2437         return 0;
2438 }
2439 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2440
2441 /**
2442  * snd_ctl_enum_info - fills the info structure for an enumerated control
2443  * @info: the structure to be filled
2444  * @channels: the number of the control's channels; often one
2445  * @items: the number of control values; also the size of @names
2446  * @names: an array containing the names of all control values
2447  *
2448  * Sets all required fields in @info to their appropriate values.
2449  * If the control's accessibility is not the default (readable and writable),
2450  * the caller has to fill @info->access.
2451  *
2452  * Return: Zero (always successful)
2453  */
2454 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2455                       unsigned int items, const char *const names[])
2456 {
2457         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2458         info->count = channels;
2459         info->value.enumerated.items = items;
2460         if (!items)
2461                 return 0;
2462         if (info->value.enumerated.item >= items)
2463                 info->value.enumerated.item = items - 1;
2464         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2465              "ALSA: too long item name '%s'\n",
2466              names[info->value.enumerated.item]);
2467         strscpy(info->value.enumerated.name,
2468                 names[info->value.enumerated.item],
2469                 sizeof(info->value.enumerated.name));
2470         return 0;
2471 }
2472 EXPORT_SYMBOL(snd_ctl_enum_info);