sound/core/control.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Routines for driver control interface
   4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   5  */
   6
   7 #include <linux/threads.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/slab.h>
  12 #include <linux/vmalloc.h>
  13 #include <linux/time.h>
  14 #include <linux/mm.h>
  15 #include <linux/math64.h>
  16 #include <linux/sched/signal.h>
  17 #include <sound/core.h>
  18 #include <sound/minors.h>
  19 #include <sound/info.h>
  20 #include <sound/control.h>
  21
  22 // Max allocation size for user controls.
  23 static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
  24 module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
  25 MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
  26
  27 #define MAX_CONTROL_COUNT       1028
  28
  29 struct snd_kctl_ioctl {
  30         struct list_head list;          /* list of all ioctls */
  31         snd_kctl_ioctl_func_t fioctl;
  32 };
  33
  34 static DECLARE_RWSEM(snd_ioctl_rwsem);
  35 static DECLARE_RWSEM(snd_ctl_layer_rwsem);
  36 static LIST_HEAD(snd_control_ioctls);
  37 #ifdef CONFIG_COMPAT
  38 static LIST_HEAD(snd_control_compat_ioctls);
  39 #endif
  40 static struct snd_ctl_layer_ops *snd_ctl_layer;
  41
  42 static int snd_ctl_open(struct inode *inode, struct file *file)
  43 {
  44         unsigned long flags;
  45         struct snd_card *card;
  46         struct snd_ctl_file *ctl;
  47         int i, err;
  48
  49         err = stream_open(inode, file);
  50         if (err < 0)
  51                 return err;
  52
  53         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  54         if (!card) {
  55                 err = -ENODEV;
  56                 goto __error1;
  57         }
  58         err = snd_card_file_add(card, file);
  59         if (err < 0) {
  60                 err = -ENODEV;
  61                 goto __error1;
  62         }
  63         if (!try_module_get(card->module)) {
  64                 err = -EFAULT;
  65                 goto __error2;
  66         }
  67         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  68         if (ctl == NULL) {
  69                 err = -ENOMEM;
  70                 goto __error;
  71         }
  72         INIT_LIST_HEAD(&ctl->events);
  73         init_waitqueue_head(&ctl->change_sleep);
  74         spin_lock_init(&ctl->read_lock);
  75         ctl->card = card;
  76         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  77                 ctl->preferred_subdevice[i] = -1;
  78         ctl->pid = get_pid(task_pid(current));
  79         file->private_data = ctl;
  80         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  81         list_add_tail(&ctl->list, &card->ctl_files);
  82         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  83         snd_card_unref(card);
  84         return 0;
  85
  86       __error:
  87         module_put(card->module);
  88       __error2:
  89         snd_card_file_remove(card, file);
  90       __error1:
  91         if (card)
  92                 snd_card_unref(card);
  93         return err;
  94 }
  95
  96 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  97 {
  98         unsigned long flags;
  99         struct snd_kctl_event *cread;
 100
 101         spin_lock_irqsave(&ctl->read_lock, flags);
 102         while (!list_empty(&ctl->events)) {
 103                 cread = snd_kctl_event(ctl->events.next);
 104                 list_del(&cread->list);
 105                 kfree(cread);
 106         }
 107         spin_unlock_irqrestore(&ctl->read_lock, flags);
 108 }
 109
 110 static int snd_ctl_release(struct inode *inode, struct file *file)
 111 {
 112         unsigned long flags;
 113         struct snd_card *card;
 114         struct snd_ctl_file *ctl;
 115         struct snd_kcontrol *control;
 116         unsigned int idx;
 117
 118         ctl = file->private_data;
 119         file->private_data = NULL;
 120         card = ctl->card;
 121         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 122         list_del(&ctl->list);
 123         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 124         down_write(&card->controls_rwsem);
 125         list_for_each_entry(control, &card->controls, list)
 126                 for (idx = 0; idx < control->count; idx++)
 127                         if (control->vd[idx].owner == ctl)
 128                                 control->vd[idx].owner = NULL;
 129         up_write(&card->controls_rwsem);
 130         snd_fasync_free(ctl->fasync);
 131         snd_ctl_empty_read_queue(ctl);
 132         put_pid(ctl->pid);
 133         kfree(ctl);
 134         module_put(card->module);
 135         snd_card_file_remove(card, file);
 136         return 0;
 137 }
 138
 139 /**
 140  * snd_ctl_notify - Send notification to user-space for a control change
 141  * @card: the card to send notification
 142  * @mask: the event mask, SNDRV_CTL_EVENT_*
 143  * @id: the ctl element id to send notification
 144  *
 145  * This function adds an event record with the given id and mask, appends
 146  * to the list and wakes up the user-space for notification.  This can be
 147  * called in the atomic context.
 148  */
 149 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 150                     struct snd_ctl_elem_id *id)
 151 {
 152         unsigned long flags;
 153         struct snd_ctl_file *ctl;
 154         struct snd_kctl_event *ev;
 155
 156         if (snd_BUG_ON(!card || !id))
 157                 return;
 158         if (card->shutdown)
 159                 return;
 160         read_lock_irqsave(&card->ctl_files_rwlock, flags);
 161 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 162         card->mixer_oss_change_count++;
 163 #endif
 164         list_for_each_entry(ctl, &card->ctl_files, list) {
 165                 if (!ctl->subscribed)
 166                         continue;
 167                 spin_lock(&ctl->read_lock);
 168                 list_for_each_entry(ev, &ctl->events, list) {
 169                         if (ev->id.numid == id->numid) {
 170                                 ev->mask |= mask;
 171                                 goto _found;
 172                         }
 173                 }
 174                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 175                 if (ev) {
 176                         ev->id = *id;
 177                         ev->mask = mask;
 178                         list_add_tail(&ev->list, &ctl->events);
 179                 } else {
 180                         dev_err(card->dev, "No memory available to allocate event\n");
 181                 }
 182         _found:
 183                 wake_up(&ctl->change_sleep);
 184                 spin_unlock(&ctl->read_lock);
 185                 snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
 186         }
 187         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 188 }
 189 EXPORT_SYMBOL(snd_ctl_notify);
 190
 191 /**
 192  * snd_ctl_notify_one - Send notification to user-space for a control change
 193  * @card: the card to send notification
 194  * @mask: the event mask, SNDRV_CTL_EVENT_*
 195  * @kctl: the pointer with the control instance
 196  * @ioff: the additional offset to the control index
 197  *
 198  * This function calls snd_ctl_notify() and does additional jobs
 199  * like LED state changes.
 200  */
 201 void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
 202                         struct snd_kcontrol *kctl, unsigned int ioff)
 203 {
 204         struct snd_ctl_elem_id id = kctl->id;
 205         struct snd_ctl_layer_ops *lops;
 206
 207         id.index += ioff;
 208         id.numid += ioff;
 209         snd_ctl_notify(card, mask, &id);
 210         down_read(&snd_ctl_layer_rwsem);
 211         for (lops = snd_ctl_layer; lops; lops = lops->next)
 212                 lops->lnotify(card, mask, kctl, ioff);
 213         up_read(&snd_ctl_layer_rwsem);
 214 }
 215 EXPORT_SYMBOL(snd_ctl_notify_one);
 216
 217 /**
 218  * snd_ctl_new - create a new control instance with some elements
 219  * @kctl: the pointer to store new control instance
 220  * @count: the number of elements in this control
 221  * @access: the default access flags for elements in this control
 222  * @file: given when locking these elements
 223  *
 224  * Allocates a memory object for a new control instance. The instance has
 225  * elements as many as the given number (@count). Each element has given
 226  * access permissions (@access). Each element is locked when @file is given.
 227  *
 228  * Return: 0 on success, error code on failure
 229  */
 230 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 231                        unsigned int access, struct snd_ctl_file *file)
 232 {
 233         unsigned int idx;
 234
 235         if (count == 0 || count > MAX_CONTROL_COUNT)
 236                 return -EINVAL;
 237
 238         *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
 239         if (!*kctl)
 240                 return -ENOMEM;
 241
 242         for (idx = 0; idx < count; idx++) {
 243                 (*kctl)->vd[idx].access = access;
 244                 (*kctl)->vd[idx].owner = file;
 245         }
 246         (*kctl)->count = count;
 247
 248         return 0;
 249 }
 250
 251 /**
 252  * snd_ctl_new1 - create a control instance from the template
 253  * @ncontrol: the initialization record
 254  * @private_data: the private data to set
 255  *
 256  * Allocates a new struct snd_kcontrol instance and initialize from the given
 257  * template.  When the access field of ncontrol is 0, it's assumed as
 258  * READWRITE access. When the count field is 0, it's assumes as one.
 259  *
 260  * Return: The pointer of the newly generated instance, or %NULL on failure.
 261  */
 262 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 263                                   void *private_data)
 264 {
 265         struct snd_kcontrol *kctl;
 266         unsigned int count;
 267         unsigned int access;
 268         int err;
 269
 270         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 271                 return NULL;
 272
 273         count = ncontrol->count;
 274         if (count == 0)
 275                 count = 1;
 276
 277         access = ncontrol->access;
 278         if (access == 0)
 279                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 280         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 281                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 282                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 283                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 284                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 285                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
 286                    SNDRV_CTL_ELEM_ACCESS_LED_MASK |
 287                    SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
 288
 289         err = snd_ctl_new(&kctl, count, access, NULL);
 290         if (err < 0)
 291                 return NULL;
 292
 293         /* The 'numid' member is decided when calling snd_ctl_add(). */
 294         kctl->id.iface = ncontrol->iface;
 295         kctl->id.device = ncontrol->device;
 296         kctl->id.subdevice = ncontrol->subdevice;
 297         if (ncontrol->name) {
 298                 strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 299                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 300                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 301                                 ncontrol->name, kctl->id.name);
 302         }
 303         kctl->id.index = ncontrol->index;
 304
 305         kctl->info = ncontrol->info;
 306         kctl->get = ncontrol->get;
 307         kctl->put = ncontrol->put;
 308         kctl->tlv.p = ncontrol->tlv.p;
 309
 310         kctl->private_value = ncontrol->private_value;
 311         kctl->private_data = private_data;
 312
 313         return kctl;
 314 }
 315 EXPORT_SYMBOL(snd_ctl_new1);
 316
 317 /**
 318  * snd_ctl_free_one - release the control instance
 319  * @kcontrol: the control instance
 320  *
 321  * Releases the control instance created via snd_ctl_new()
 322  * or snd_ctl_new1().
 323  * Don't call this after the control was added to the card.
 324  */
 325 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 326 {
 327         if (kcontrol) {
 328                 if (kcontrol->private_free)
 329                         kcontrol->private_free(kcontrol);
 330                 kfree(kcontrol);
 331         }
 332 }
 333 EXPORT_SYMBOL(snd_ctl_free_one);
 334
 335 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 336                                           unsigned int count)
 337 {
 338         struct snd_kcontrol *kctl;
 339
 340         /* Make sure that the ids assigned to the control do not wrap around */
 341         if (card->last_numid >= UINT_MAX - count)
 342                 card->last_numid = 0;
 343
 344         list_for_each_entry(kctl, &card->controls, list) {
 345                 if (kctl->id.numid < card->last_numid + 1 + count &&
 346                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 347                         card->last_numid = kctl->id.numid + kctl->count - 1;
 348                         return true;
 349                 }
 350         }
 351         return false;
 352 }
 353
 354 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 355 {
 356         unsigned int iter = 100000;
 357
 358         while (snd_ctl_remove_numid_conflict(card, count)) {
 359                 if (--iter == 0) {
 360                         /* this situation is very unlikely */
 361                         dev_err(card->dev, "unable to allocate new control numid\n");
 362                         return -ENOMEM;
 363                 }
 364         }
 365         return 0;
 366 }
 367
 368 /* 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         unsigned long h;
 389         const unsigned char *p;
 390
 391         h = id->iface;
 392         h = MULTIPLIER * h + id->device;
 393         h = MULTIPLIER * h + id->subdevice;
 394         for (p = id->name; *p; p++)
 395                 h = MULTIPLIER * h + *p;
 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 #ifndef CONFIG_SND_CTL_FAST_LOOKUP
 757 static struct snd_kcontrol *
 758 snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
 759 {
 760         struct snd_kcontrol *kctl;
 761
 762         list_for_each_entry(kctl, &card->controls, list) {
 763                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 764                         return kctl;
 765         }
 766         return NULL;
 767 }
 768 #endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
 769
 770 /**
 771  * snd_ctl_find_numid - find the control instance with the given number-id
 772  * @card: the card instance
 773  * @numid: the number-id to search
 774  *
 775  * Finds the control instance with the given number-id from the card.
 776  *
 777  * The caller must down card->controls_rwsem before calling this function
 778  * (if the race condition can happen).
 779  *
 780  * Return: The pointer of the instance if found, or %NULL if not.
 781  *
 782  */
 783 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 784 {
 785         if (snd_BUG_ON(!card || !numid))
 786                 return NULL;
 787 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 788         return xa_load(&card->ctl_numids, numid);
 789 #else
 790         return snd_ctl_find_numid_slow(card, numid);
 791 #endif
 792 }
 793 EXPORT_SYMBOL(snd_ctl_find_numid);
 794
 795 /**
 796  * snd_ctl_find_id - find the control instance with the given id
 797  * @card: the card instance
 798  * @id: the id to search
 799  *
 800  * Finds the control instance with the given id from the card.
 801  *
 802  * The caller must down card->controls_rwsem before calling this function
 803  * (if the race condition can happen).
 804  *
 805  * Return: The pointer of the instance if found, or %NULL if not.
 806  *
 807  */
 808 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 809                                      struct snd_ctl_elem_id *id)
 810 {
 811         struct snd_kcontrol *kctl;
 812
 813         if (snd_BUG_ON(!card || !id))
 814                 return NULL;
 815         if (id->numid != 0)
 816                 return snd_ctl_find_numid(card, id->numid);
 817 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 818         kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
 819         if (kctl && elem_id_matches(kctl, id))
 820                 return kctl;
 821         if (!card->ctl_hash_collision)
 822                 return NULL; /* we can rely on only hash table */
 823 #endif
 824         /* no matching in hash table - try all as the last resort */
 825         list_for_each_entry(kctl, &card->controls, list)
 826                 if (elem_id_matches(kctl, id))
 827                         return kctl;
 828
 829         return NULL;
 830 }
 831 EXPORT_SYMBOL(snd_ctl_find_id);
 832
 833 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 834                              unsigned int cmd, void __user *arg)
 835 {
 836         struct snd_ctl_card_info *info;
 837
 838         info = kzalloc(sizeof(*info), GFP_KERNEL);
 839         if (! info)
 840                 return -ENOMEM;
 841         down_read(&snd_ioctl_rwsem);
 842         info->card = card->number;
 843         strscpy(info->id, card->id, sizeof(info->id));
 844         strscpy(info->driver, card->driver, sizeof(info->driver));
 845         strscpy(info->name, card->shortname, sizeof(info->name));
 846         strscpy(info->longname, card->longname, sizeof(info->longname));
 847         strscpy(info->mixername, card->mixername, sizeof(info->mixername));
 848         strscpy(info->components, card->components, sizeof(info->components));
 849         up_read(&snd_ioctl_rwsem);
 850         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 851                 kfree(info);
 852                 return -EFAULT;
 853         }
 854         kfree(info);
 855         return 0;
 856 }
 857
 858 static int snd_ctl_elem_list(struct snd_card *card,
 859                              struct snd_ctl_elem_list *list)
 860 {
 861         struct snd_kcontrol *kctl;
 862         struct snd_ctl_elem_id id;
 863         unsigned int offset, space, jidx;
 864         int err = 0;
 865
 866         offset = list->offset;
 867         space = list->space;
 868
 869         down_read(&card->controls_rwsem);
 870         list->count = card->controls_count;
 871         list->used = 0;
 872         if (space > 0) {
 873                 list_for_each_entry(kctl, &card->controls, list) {
 874                         if (offset >= kctl->count) {
 875                                 offset -= kctl->count;
 876                                 continue;
 877                         }
 878                         for (jidx = offset; jidx < kctl->count; jidx++) {
 879                                 snd_ctl_build_ioff(&id, kctl, jidx);
 880                                 if (copy_to_user(list->pids + list->used, &id,
 881                                                  sizeof(id))) {
 882                                         err = -EFAULT;
 883                                         goto out;
 884                                 }
 885                                 list->used++;
 886                                 if (!--space)
 887                                         goto out;
 888                         }
 889                         offset = 0;
 890                 }
 891         }
 892  out:
 893         up_read(&card->controls_rwsem);
 894         return err;
 895 }
 896
 897 static int snd_ctl_elem_list_user(struct snd_card *card,
 898                                   struct snd_ctl_elem_list __user *_list)
 899 {
 900         struct snd_ctl_elem_list list;
 901         int err;
 902
 903         if (copy_from_user(&list, _list, sizeof(list)))
 904                 return -EFAULT;
 905         err = snd_ctl_elem_list(card, &list);
 906         if (err)
 907                 return err;
 908         if (copy_to_user(_list, &list, sizeof(list)))
 909                 return -EFAULT;
 910
 911         return 0;
 912 }
 913
 914 /* Check whether the given kctl info is valid */
 915 static int snd_ctl_check_elem_info(struct snd_card *card,
 916                                    const struct snd_ctl_elem_info *info)
 917 {
 918         static const unsigned int max_value_counts[] = {
 919                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
 920                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
 921                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
 922                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
 923                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
 924                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
 925         };
 926
 927         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
 928             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
 929                 if (card)
 930                         dev_err(card->dev,
 931                                 "control %i:%i:%i:%s:%i: invalid type %d\n",
 932                                 info->id.iface, info->id.device,
 933                                 info->id.subdevice, info->id.name,
 934                                 info->id.index, info->type);
 935                 return -EINVAL;
 936         }
 937         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
 938             info->value.enumerated.items == 0) {
 939                 if (card)
 940                         dev_err(card->dev,
 941                                 "control %i:%i:%i:%s:%i: zero enum items\n",
 942                                 info->id.iface, info->id.device,
 943                                 info->id.subdevice, info->id.name,
 944                                 info->id.index);
 945                 return -EINVAL;
 946         }
 947         if (info->count > max_value_counts[info->type]) {
 948                 if (card)
 949                         dev_err(card->dev,
 950                                 "control %i:%i:%i:%s:%i: invalid count %d\n",
 951                                 info->id.iface, info->id.device,
 952                                 info->id.subdevice, info->id.name,
 953                                 info->id.index, info->count);
 954                 return -EINVAL;
 955         }
 956
 957         return 0;
 958 }
 959
 960 /* The capacity of struct snd_ctl_elem_value.value.*/
 961 static const unsigned int value_sizes[] = {
 962         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
 963         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
 964         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
 965         [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
 966         [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
 967         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
 968 };
 969
 970 /* fill the remaining snd_ctl_elem_value data with the given pattern */
 971 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 972                                       struct snd_ctl_elem_info *info,
 973                                       u32 pattern)
 974 {
 975         size_t offset = value_sizes[info->type] * info->count;
 976
 977         offset = DIV_ROUND_UP(offset, sizeof(u32));
 978         memset32((u32 *)control->value.bytes.data + offset, pattern,
 979                  sizeof(control->value) / sizeof(u32) - offset);
 980 }
 981
 982 /* check whether the given integer ctl value is valid */
 983 static int sanity_check_int_value(struct snd_card *card,
 984                                   const struct snd_ctl_elem_value *control,
 985                                   const struct snd_ctl_elem_info *info,
 986                                   int i, bool print_error)
 987 {
 988         long long lval, lmin, lmax, lstep;
 989         u64 rem;
 990
 991         switch (info->type) {
 992         default:
 993         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 994                 lval = control->value.integer.value[i];
 995                 lmin = 0;
 996                 lmax = 1;
 997                 lstep = 0;
 998                 break;
 999         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1000                 lval = control->value.integer.value[i];
1001                 lmin = info->value.integer.min;
1002                 lmax = info->value.integer.max;
1003                 lstep = info->value.integer.step;
1004                 break;
1005         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1006                 lval = control->value.integer64.value[i];
1007                 lmin = info->value.integer64.min;
1008                 lmax = info->value.integer64.max;
1009                 lstep = info->value.integer64.step;
1010                 break;
1011         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1012                 lval = control->value.enumerated.item[i];
1013                 lmin = 0;
1014                 lmax = info->value.enumerated.items - 1;
1015                 lstep = 0;
1016                 break;
1017         }
1018
1019         if (lval < lmin || lval > lmax) {
1020                 if (print_error)
1021                         dev_err(card->dev,
1022                                 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
1023                                 control->id.iface, control->id.device,
1024                                 control->id.subdevice, control->id.name,
1025                                 control->id.index, lval, lmin, lmax, i);
1026                 return -EINVAL;
1027         }
1028         if (lstep) {
1029                 div64_u64_rem(lval, lstep, &rem);
1030                 if (rem) {
1031                         if (print_error)
1032                                 dev_err(card->dev,
1033                                         "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
1034                                         control->id.iface, control->id.device,
1035                                         control->id.subdevice, control->id.name,
1036                                         control->id.index, lval, lstep, i);
1037                         return -EINVAL;
1038                 }
1039         }
1040
1041         return 0;
1042 }
1043
1044 /* check whether the all input values are valid for the given elem value */
1045 static int sanity_check_input_values(struct snd_card *card,
1046                                      const struct snd_ctl_elem_value *control,
1047                                      const struct snd_ctl_elem_info *info,
1048                                      bool print_error)
1049 {
1050         int i, ret;
1051
1052         switch (info->type) {
1053         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1054         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1055         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1056         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1057                 for (i = 0; i < info->count; i++) {
1058                         ret = sanity_check_int_value(card, control, info, i,
1059                                                      print_error);
1060                         if (ret < 0)
1061                                 return ret;
1062                 }
1063                 break;
1064         default:
1065                 break;
1066         }
1067
1068         return 0;
1069 }
1070
1071 /* perform sanity checks to the given snd_ctl_elem_value object */
1072 static int sanity_check_elem_value(struct snd_card *card,
1073                                    const struct snd_ctl_elem_value *control,
1074                                    const struct snd_ctl_elem_info *info,
1075                                    u32 pattern)
1076 {
1077         size_t offset;
1078         int ret;
1079         u32 *p;
1080
1081         ret = sanity_check_input_values(card, control, info, true);
1082         if (ret < 0)
1083                 return ret;
1084
1085         /* check whether the remaining area kept untouched */
1086         offset = value_sizes[info->type] * info->count;
1087         offset = DIV_ROUND_UP(offset, sizeof(u32));
1088         p = (u32 *)control->value.bytes.data + offset;
1089         for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
1090                 if (*p != pattern) {
1091                         ret = -EINVAL;
1092                         break;
1093                 }
1094                 *p = 0; /* clear the checked area */
1095         }
1096
1097         return ret;
1098 }
1099
1100 static int __snd_ctl_elem_info(struct snd_card *card,
1101                                struct snd_kcontrol *kctl,
1102                                struct snd_ctl_elem_info *info,
1103                                struct snd_ctl_file *ctl)
1104 {
1105         struct snd_kcontrol_volatile *vd;
1106         unsigned int index_offset;
1107         int result;
1108
1109 #ifdef CONFIG_SND_DEBUG
1110         info->access = 0;
1111 #endif
1112         result = snd_power_ref_and_wait(card);
1113         if (!result)
1114                 result = kctl->info(kctl, info);
1115         snd_power_unref(card);
1116         if (result >= 0) {
1117                 snd_BUG_ON(info->access);
1118                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
1119                 vd = &kctl->vd[index_offset];
1120                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
1121                 info->access = vd->access;
1122                 if (vd->owner) {
1123                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
1124                         if (vd->owner == ctl)
1125                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
1126                         info->owner = pid_vnr(vd->owner->pid);
1127                 } else {
1128                         info->owner = -1;
1129                 }
1130                 if (!snd_ctl_skip_validation(info) &&
1131                     snd_ctl_check_elem_info(card, info) < 0)
1132                         result = -EINVAL;
1133         }
1134         return result;
1135 }
1136
1137 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
1138                              struct snd_ctl_elem_info *info)
1139 {
1140         struct snd_card *card = ctl->card;
1141         struct snd_kcontrol *kctl;
1142         int result;
1143
1144         down_read(&card->controls_rwsem);
1145         kctl = snd_ctl_find_id(card, &info->id);
1146         if (kctl == NULL)
1147                 result = -ENOENT;
1148         else
1149                 result = __snd_ctl_elem_info(card, kctl, info, ctl);
1150         up_read(&card->controls_rwsem);
1151         return result;
1152 }
1153
1154 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1155                                   struct snd_ctl_elem_info __user *_info)
1156 {
1157         struct snd_ctl_elem_info info;
1158         int result;
1159
1160         if (copy_from_user(&info, _info, sizeof(info)))
1161                 return -EFAULT;
1162         result = snd_ctl_elem_info(ctl, &info);
1163         if (result < 0)
1164                 return result;
1165         /* drop internal access flags */
1166         info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
1167                          SNDRV_CTL_ELEM_ACCESS_LED_MASK);
1168         if (copy_to_user(_info, &info, sizeof(info)))
1169                 return -EFAULT;
1170         return result;
1171 }
1172
1173 static int snd_ctl_elem_read(struct snd_card *card,
1174                              struct snd_ctl_elem_value *control)
1175 {
1176         struct snd_kcontrol *kctl;
1177         struct snd_kcontrol_volatile *vd;
1178         unsigned int index_offset;
1179         struct snd_ctl_elem_info info;
1180         const u32 pattern = 0xdeadbeef;
1181         int ret;
1182
1183         kctl = snd_ctl_find_id(card, &control->id);
1184         if (kctl == NULL)
1185                 return -ENOENT;
1186
1187         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1188         vd = &kctl->vd[index_offset];
1189         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1190                 return -EPERM;
1191
1192         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1193
1194 #ifdef CONFIG_SND_CTL_DEBUG
1195         /* info is needed only for validation */
1196         memset(&info, 0, sizeof(info));
1197         info.id = control->id;
1198         ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1199         if (ret < 0)
1200                 return ret;
1201 #endif
1202
1203         if (!snd_ctl_skip_validation(&info))
1204                 fill_remaining_elem_value(control, &info, pattern);
1205         ret = snd_power_ref_and_wait(card);
1206         if (!ret)
1207                 ret = kctl->get(kctl, control);
1208         snd_power_unref(card);
1209         if (ret < 0)
1210                 return ret;
1211         if (!snd_ctl_skip_validation(&info) &&
1212             sanity_check_elem_value(card, control, &info, pattern) < 0) {
1213                 dev_err(card->dev,
1214                         "control %i:%i:%i:%s:%i: access overflow\n",
1215                         control->id.iface, control->id.device,
1216                         control->id.subdevice, control->id.name,
1217                         control->id.index);
1218                 return -EINVAL;
1219         }
1220         return ret;
1221 }
1222
1223 static int snd_ctl_elem_read_user(struct snd_card *card,
1224                                   struct snd_ctl_elem_value __user *_control)
1225 {
1226         struct snd_ctl_elem_value *control;
1227         int result;
1228
1229         control = memdup_user(_control, sizeof(*control));
1230         if (IS_ERR(control))
1231                 return PTR_ERR(control);
1232
1233         down_read(&card->controls_rwsem);
1234         result = snd_ctl_elem_read(card, control);
1235         up_read(&card->controls_rwsem);
1236         if (result < 0)
1237                 goto error;
1238
1239         if (copy_to_user(_control, control, sizeof(*control)))
1240                 result = -EFAULT;
1241  error:
1242         kfree(control);
1243         return result;
1244 }
1245
1246 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1247                               struct snd_ctl_elem_value *control)
1248 {
1249         struct snd_kcontrol *kctl;
1250         struct snd_kcontrol_volatile *vd;
1251         unsigned int index_offset;
1252         int result;
1253
1254         down_write(&card->controls_rwsem);
1255         kctl = snd_ctl_find_id(card, &control->id);
1256         if (kctl == NULL) {
1257                 up_write(&card->controls_rwsem);
1258                 return -ENOENT;
1259         }
1260
1261         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1262         vd = &kctl->vd[index_offset];
1263         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1264             (file && vd->owner && vd->owner != file)) {
1265                 up_write(&card->controls_rwsem);
1266                 return -EPERM;
1267         }
1268
1269         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1270         result = snd_power_ref_and_wait(card);
1271         /* validate input values */
1272         if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION) && !result) {
1273                 struct snd_ctl_elem_info info;
1274
1275                 memset(&info, 0, sizeof(info));
1276                 info.id = control->id;
1277                 result = __snd_ctl_elem_info(card, kctl, &info, NULL);
1278                 if (!result)
1279                         result = sanity_check_input_values(card, control, &info,
1280                                                            false);
1281         }
1282         if (!result)
1283                 result = kctl->put(kctl, control);
1284         snd_power_unref(card);
1285         if (result < 0) {
1286                 up_write(&card->controls_rwsem);
1287                 return result;
1288         }
1289
1290         if (result > 0) {
1291                 downgrade_write(&card->controls_rwsem);
1292                 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
1293                 up_read(&card->controls_rwsem);
1294         } else {
1295                 up_write(&card->controls_rwsem);
1296         }
1297
1298         return 0;
1299 }
1300
1301 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1302                                    struct snd_ctl_elem_value __user *_control)
1303 {
1304         struct snd_ctl_elem_value *control;
1305         struct snd_card *card;
1306         int result;
1307
1308         control = memdup_user(_control, sizeof(*control));
1309         if (IS_ERR(control))
1310                 return PTR_ERR(control);
1311
1312         card = file->card;
1313         result = snd_ctl_elem_write(card, file, control);
1314         if (result < 0)
1315                 goto error;
1316
1317         if (copy_to_user(_control, control, sizeof(*control)))
1318                 result = -EFAULT;
1319  error:
1320         kfree(control);
1321         return result;
1322 }
1323
1324 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1325                              struct snd_ctl_elem_id __user *_id)
1326 {
1327         struct snd_card *card = file->card;
1328         struct snd_ctl_elem_id id;
1329         struct snd_kcontrol *kctl;
1330         struct snd_kcontrol_volatile *vd;
1331         int result;
1332
1333         if (copy_from_user(&id, _id, sizeof(id)))
1334                 return -EFAULT;
1335         down_write(&card->controls_rwsem);
1336         kctl = snd_ctl_find_id(card, &id);
1337         if (kctl == NULL) {
1338                 result = -ENOENT;
1339         } else {
1340                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1341                 if (vd->owner != NULL)
1342                         result = -EBUSY;
1343                 else {
1344                         vd->owner = file;
1345                         result = 0;
1346                 }
1347         }
1348         up_write(&card->controls_rwsem);
1349         return result;
1350 }
1351
1352 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1353                                struct snd_ctl_elem_id __user *_id)
1354 {
1355         struct snd_card *card = file->card;
1356         struct snd_ctl_elem_id id;
1357         struct snd_kcontrol *kctl;
1358         struct snd_kcontrol_volatile *vd;
1359         int result;
1360
1361         if (copy_from_user(&id, _id, sizeof(id)))
1362                 return -EFAULT;
1363         down_write(&card->controls_rwsem);
1364         kctl = snd_ctl_find_id(card, &id);
1365         if (kctl == NULL) {
1366                 result = -ENOENT;
1367         } else {
1368                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1369                 if (vd->owner == NULL)
1370                         result = -EINVAL;
1371                 else if (vd->owner != file)
1372                         result = -EPERM;
1373                 else {
1374                         vd->owner = NULL;
1375                         result = 0;
1376                 }
1377         }
1378         up_write(&card->controls_rwsem);
1379         return result;
1380 }
1381
1382 struct user_element {
1383         struct snd_ctl_elem_info info;
1384         struct snd_card *card;
1385         char *elem_data;                /* element data */
1386         unsigned long elem_data_size;   /* size of element data in bytes */
1387         void *tlv_data;                 /* TLV data */
1388         unsigned long tlv_data_size;    /* TLV data size */
1389         void *priv_data;                /* private data (like strings for enumerated type) */
1390 };
1391
1392 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1393 static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
1394 {
1395         return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
1396 }
1397
1398 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1399                                   struct snd_ctl_elem_info *uinfo)
1400 {
1401         struct user_element *ue = kcontrol->private_data;
1402         unsigned int offset;
1403
1404         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1405         *uinfo = ue->info;
1406         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1407
1408         return 0;
1409 }
1410
1411 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1412                                        struct snd_ctl_elem_info *uinfo)
1413 {
1414         struct user_element *ue = kcontrol->private_data;
1415         const char *names;
1416         unsigned int item;
1417         unsigned int offset;
1418
1419         item = uinfo->value.enumerated.item;
1420
1421         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1422         *uinfo = ue->info;
1423         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1424
1425         item = min(item, uinfo->value.enumerated.items - 1);
1426         uinfo->value.enumerated.item = item;
1427
1428         names = ue->priv_data;
1429         for (; item > 0; --item)
1430                 names += strlen(names) + 1;
1431         strcpy(uinfo->value.enumerated.name, names);
1432
1433         return 0;
1434 }
1435
1436 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1437                                  struct snd_ctl_elem_value *ucontrol)
1438 {
1439         struct user_element *ue = kcontrol->private_data;
1440         unsigned int size = ue->elem_data_size;
1441         char *src = ue->elem_data +
1442                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1443
1444         memcpy(&ucontrol->value, src, size);
1445         return 0;
1446 }
1447
1448 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1449                                  struct snd_ctl_elem_value *ucontrol)
1450 {
1451         int change;
1452         struct user_element *ue = kcontrol->private_data;
1453         unsigned int size = ue->elem_data_size;
1454         char *dst = ue->elem_data +
1455                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1456
1457         change = memcmp(&ucontrol->value, dst, size) != 0;
1458         if (change)
1459                 memcpy(dst, &ucontrol->value, size);
1460         return change;
1461 }
1462
1463 /* called in controls_rwsem write lock */
1464 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1465                             unsigned int size)
1466 {
1467         struct user_element *ue = kctl->private_data;
1468         unsigned int *container;
1469         unsigned int mask = 0;
1470         int i;
1471         int change;
1472
1473         if (size > 1024 * 128)  /* sane value */
1474                 return -EINVAL;
1475
1476         // does the TLV size change cause overflow?
1477         if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
1478                 return -ENOMEM;
1479
1480         container = vmemdup_user(buf, size);
1481         if (IS_ERR(container))
1482                 return PTR_ERR(container);
1483
1484         change = ue->tlv_data_size != size;
1485         if (!change)
1486                 change = memcmp(ue->tlv_data, container, size) != 0;
1487         if (!change) {
1488                 kvfree(container);
1489                 return 0;
1490         }
1491
1492         if (ue->tlv_data == NULL) {
1493                 /* Now TLV data is available. */
1494                 for (i = 0; i < kctl->count; ++i)
1495                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1496                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1497         } else {
1498                 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1499                 ue->tlv_data_size = 0;
1500                 kvfree(ue->tlv_data);
1501         }
1502
1503         ue->tlv_data = container;
1504         ue->tlv_data_size = size;
1505         // decremented at private_free.
1506         ue->card->user_ctl_alloc_size += size;
1507
1508         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1509         for (i = 0; i < kctl->count; ++i)
1510                 snd_ctl_notify_one(ue->card, mask, kctl, i);
1511
1512         return change;
1513 }
1514
1515 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1516                          unsigned int size)
1517 {
1518         struct user_element *ue = kctl->private_data;
1519
1520         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1521                 return -ENXIO;
1522
1523         if (size < ue->tlv_data_size)
1524                 return -ENOSPC;
1525
1526         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1527                 return -EFAULT;
1528
1529         return 0;
1530 }
1531
1532 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1533                                  unsigned int size, unsigned int __user *buf)
1534 {
1535         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1536                 return replace_user_tlv(kctl, buf, size);
1537         else
1538                 return read_user_tlv(kctl, buf, size);
1539 }
1540
1541 /* called in controls_rwsem write lock */
1542 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1543 {
1544         char *names, *p;
1545         size_t buf_len, name_len;
1546         unsigned int i;
1547         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1548
1549         buf_len = ue->info.value.enumerated.names_length;
1550         if (buf_len > 64 * 1024)
1551                 return -EINVAL;
1552
1553         if (check_user_elem_overflow(ue->card, buf_len))
1554                 return -ENOMEM;
1555         names = vmemdup_user((const void __user *)user_ptrval, buf_len);
1556         if (IS_ERR(names))
1557                 return PTR_ERR(names);
1558
1559         /* check that there are enough valid names */
1560         p = names;
1561         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1562                 name_len = strnlen(p, buf_len);
1563                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1564                         kvfree(names);
1565                         return -EINVAL;
1566                 }
1567                 p += name_len + 1;
1568                 buf_len -= name_len + 1;
1569         }
1570
1571         ue->priv_data = names;
1572         ue->info.value.enumerated.names_ptr = 0;
1573         // increment the allocation size; decremented again at private_free.
1574         ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
1575
1576         return 0;
1577 }
1578
1579 static size_t compute_user_elem_size(size_t size, unsigned int count)
1580 {
1581         return sizeof(struct user_element) + size * count;
1582 }
1583
1584 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1585 {
1586         struct user_element *ue = kcontrol->private_data;
1587
1588         // decrement the allocation size.
1589         ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
1590         ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1591         if (ue->priv_data)
1592                 ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
1593
1594         kvfree(ue->tlv_data);
1595         kvfree(ue->priv_data);
1596         kfree(ue);
1597 }
1598
1599 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1600                             struct snd_ctl_elem_info *info, int replace)
1601 {
1602         struct snd_card *card = file->card;
1603         struct snd_kcontrol *kctl;
1604         unsigned int count;
1605         unsigned int access;
1606         long private_size;
1607         size_t alloc_size;
1608         struct user_element *ue;
1609         unsigned int offset;
1610         int err;
1611
1612         if (!*info->id.name)
1613                 return -EINVAL;
1614         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1615                 return -EINVAL;
1616
1617         /* Delete a control to replace them if needed. */
1618         if (replace) {
1619                 info->id.numid = 0;
1620                 err = snd_ctl_remove_user_ctl(file, &info->id);
1621                 if (err)
1622                         return err;
1623         }
1624
1625         /* Check the number of elements for this userspace control. */
1626         count = info->owner;
1627         if (count == 0)
1628                 count = 1;
1629
1630         /* Arrange access permissions if needed. */
1631         access = info->access;
1632         if (access == 0)
1633                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1634         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1635                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1636                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1637
1638         /* In initial state, nothing is available as TLV container. */
1639         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1640                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1641         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1642
1643         /*
1644          * Check information and calculate the size of data specific to
1645          * this userspace control.
1646          */
1647         /* pass NULL to card for suppressing error messages */
1648         err = snd_ctl_check_elem_info(NULL, info);
1649         if (err < 0)
1650                 return err;
1651         /* user-space control doesn't allow zero-size data */
1652         if (info->count < 1)
1653                 return -EINVAL;
1654         private_size = value_sizes[info->type] * info->count;
1655         alloc_size = compute_user_elem_size(private_size, count);
1656
1657         down_write(&card->controls_rwsem);
1658         if (check_user_elem_overflow(card, alloc_size)) {
1659                 err = -ENOMEM;
1660                 goto unlock;
1661         }
1662
1663         /*
1664          * Keep memory object for this userspace control. After passing this
1665          * code block, the instance should be freed by snd_ctl_free_one().
1666          *
1667          * Note that these elements in this control are locked.
1668          */
1669         err = snd_ctl_new(&kctl, count, access, file);
1670         if (err < 0)
1671                 goto unlock;
1672         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1673         ue = kzalloc(alloc_size, GFP_KERNEL);
1674         if (!ue) {
1675                 kfree(kctl);
1676                 err = -ENOMEM;
1677                 goto unlock;
1678         }
1679         kctl->private_data = ue;
1680         kctl->private_free = snd_ctl_elem_user_free;
1681
1682         // increment the allocated size; decremented again at private_free.
1683         card->user_ctl_alloc_size += alloc_size;
1684
1685         /* Set private data for this userspace control. */
1686         ue->card = card;
1687         ue->info = *info;
1688         ue->info.access = 0;
1689         ue->elem_data = (char *)ue + sizeof(*ue);
1690         ue->elem_data_size = private_size;
1691         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1692                 err = snd_ctl_elem_init_enum_names(ue);
1693                 if (err < 0) {
1694                         snd_ctl_free_one(kctl);
1695                         goto unlock;
1696                 }
1697         }
1698
1699         /* Set callback functions. */
1700         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1701                 kctl->info = snd_ctl_elem_user_enum_info;
1702         else
1703                 kctl->info = snd_ctl_elem_user_info;
1704         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1705                 kctl->get = snd_ctl_elem_user_get;
1706         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1707                 kctl->put = snd_ctl_elem_user_put;
1708         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1709                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1710
1711         /* This function manage to free the instance on failure. */
1712         err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1713         if (err < 0) {
1714                 snd_ctl_free_one(kctl);
1715                 goto unlock;
1716         }
1717         offset = snd_ctl_get_ioff(kctl, &info->id);
1718         snd_ctl_build_ioff(&info->id, kctl, offset);
1719         /*
1720          * Here we cannot fill any field for the number of elements added by
1721          * this operation because there're no specific fields. The usage of
1722          * 'owner' field for this purpose may cause any bugs to userspace
1723          * applications because the field originally means PID of a process
1724          * which locks the element.
1725          */
1726  unlock:
1727         up_write(&card->controls_rwsem);
1728         return err;
1729 }
1730
1731 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1732                                  struct snd_ctl_elem_info __user *_info, int replace)
1733 {
1734         struct snd_ctl_elem_info info;
1735         int err;
1736
1737         if (copy_from_user(&info, _info, sizeof(info)))
1738                 return -EFAULT;
1739         err = snd_ctl_elem_add(file, &info, replace);
1740         if (err < 0)
1741                 return err;
1742         if (copy_to_user(_info, &info, sizeof(info))) {
1743                 snd_ctl_remove_user_ctl(file, &info.id);
1744                 return -EFAULT;
1745         }
1746
1747         return 0;
1748 }
1749
1750 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1751                                struct snd_ctl_elem_id __user *_id)
1752 {
1753         struct snd_ctl_elem_id id;
1754
1755         if (copy_from_user(&id, _id, sizeof(id)))
1756                 return -EFAULT;
1757         return snd_ctl_remove_user_ctl(file, &id);
1758 }
1759
1760 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1761 {
1762         int subscribe;
1763         if (get_user(subscribe, ptr))
1764                 return -EFAULT;
1765         if (subscribe < 0) {
1766                 subscribe = file->subscribed;
1767                 if (put_user(subscribe, ptr))
1768                         return -EFAULT;
1769                 return 0;
1770         }
1771         if (subscribe) {
1772                 file->subscribed = 1;
1773                 return 0;
1774         } else if (file->subscribed) {
1775                 snd_ctl_empty_read_queue(file);
1776                 file->subscribed = 0;
1777         }
1778         return 0;
1779 }
1780
1781 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1782                             struct snd_kcontrol *kctl,
1783                             struct snd_ctl_elem_id *id,
1784                             unsigned int __user *buf, unsigned int size)
1785 {
1786         static const struct {
1787                 int op;
1788                 int perm;
1789         } pairs[] = {
1790                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1791                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1792                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1793         };
1794         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1795         int i, ret;
1796
1797         /* Check support of the request for this element. */
1798         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1799                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1800                         break;
1801         }
1802         if (i == ARRAY_SIZE(pairs))
1803                 return -ENXIO;
1804
1805         if (kctl->tlv.c == NULL)
1806                 return -ENXIO;
1807
1808         /* Write and command operations are not allowed for locked element. */
1809         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1810             vd->owner != NULL && vd->owner != file)
1811                 return -EPERM;
1812
1813         ret = snd_power_ref_and_wait(file->card);
1814         if (!ret)
1815                 ret = kctl->tlv.c(kctl, op_flag, size, buf);
1816         snd_power_unref(file->card);
1817         return ret;
1818 }
1819
1820 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1821                         unsigned int __user *buf, unsigned int size)
1822 {
1823         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1824         unsigned int len;
1825
1826         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1827                 return -ENXIO;
1828
1829         if (kctl->tlv.p == NULL)
1830                 return -ENXIO;
1831
1832         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1833         if (size < len)
1834                 return -ENOMEM;
1835
1836         if (copy_to_user(buf, kctl->tlv.p, len))
1837                 return -EFAULT;
1838
1839         return 0;
1840 }
1841
1842 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1843                              struct snd_ctl_tlv __user *buf,
1844                              int op_flag)
1845 {
1846         struct snd_ctl_tlv header;
1847         unsigned int __user *container;
1848         unsigned int container_size;
1849         struct snd_kcontrol *kctl;
1850         struct snd_ctl_elem_id id;
1851         struct snd_kcontrol_volatile *vd;
1852
1853         if (copy_from_user(&header, buf, sizeof(header)))
1854                 return -EFAULT;
1855
1856         /* In design of control core, numerical ID starts at 1. */
1857         if (header.numid == 0)
1858                 return -EINVAL;
1859
1860         /* At least, container should include type and length fields.  */
1861         if (header.length < sizeof(unsigned int) * 2)
1862                 return -EINVAL;
1863         container_size = header.length;
1864         container = buf->tlv;
1865
1866         kctl = snd_ctl_find_numid(file->card, header.numid);
1867         if (kctl == NULL)
1868                 return -ENOENT;
1869
1870         /* Calculate index of the element in this set. */
1871         id = kctl->id;
1872         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1873         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1874
1875         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1876                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1877                                         container_size);
1878         } else {
1879                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1880                         return read_tlv_buf(kctl, &id, container,
1881                                             container_size);
1882                 }
1883         }
1884
1885         /* Not supported. */
1886         return -ENXIO;
1887 }
1888
1889 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1890 {
1891         struct snd_ctl_file *ctl;
1892         struct snd_card *card;
1893         struct snd_kctl_ioctl *p;
1894         void __user *argp = (void __user *)arg;
1895         int __user *ip = argp;
1896         int err;
1897
1898         ctl = file->private_data;
1899         card = ctl->card;
1900         if (snd_BUG_ON(!card))
1901                 return -ENXIO;
1902         switch (cmd) {
1903         case SNDRV_CTL_IOCTL_PVERSION:
1904                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1905         case SNDRV_CTL_IOCTL_CARD_INFO:
1906                 return snd_ctl_card_info(card, ctl, cmd, argp);
1907         case SNDRV_CTL_IOCTL_ELEM_LIST:
1908                 return snd_ctl_elem_list_user(card, argp);
1909         case SNDRV_CTL_IOCTL_ELEM_INFO:
1910                 return snd_ctl_elem_info_user(ctl, argp);
1911         case SNDRV_CTL_IOCTL_ELEM_READ:
1912                 return snd_ctl_elem_read_user(card, argp);
1913         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1914                 return snd_ctl_elem_write_user(ctl, argp);
1915         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1916                 return snd_ctl_elem_lock(ctl, argp);
1917         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1918                 return snd_ctl_elem_unlock(ctl, argp);
1919         case SNDRV_CTL_IOCTL_ELEM_ADD:
1920                 return snd_ctl_elem_add_user(ctl, argp, 0);
1921         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1922                 return snd_ctl_elem_add_user(ctl, argp, 1);
1923         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1924                 return snd_ctl_elem_remove(ctl, argp);
1925         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1926                 return snd_ctl_subscribe_events(ctl, ip);
1927         case SNDRV_CTL_IOCTL_TLV_READ:
1928                 down_read(&ctl->card->controls_rwsem);
1929                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1930                 up_read(&ctl->card->controls_rwsem);
1931                 return err;
1932         case SNDRV_CTL_IOCTL_TLV_WRITE:
1933                 down_write(&ctl->card->controls_rwsem);
1934                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1935                 up_write(&ctl->card->controls_rwsem);
1936                 return err;
1937         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1938                 down_write(&ctl->card->controls_rwsem);
1939                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1940                 up_write(&ctl->card->controls_rwsem);
1941                 return err;
1942         case SNDRV_CTL_IOCTL_POWER:
1943                 return -ENOPROTOOPT;
1944         case SNDRV_CTL_IOCTL_POWER_STATE:
1945                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1946         }
1947         down_read(&snd_ioctl_rwsem);
1948         list_for_each_entry(p, &snd_control_ioctls, list) {
1949                 err = p->fioctl(card, ctl, cmd, arg);
1950                 if (err != -ENOIOCTLCMD) {
1951                         up_read(&snd_ioctl_rwsem);
1952                         return err;
1953                 }
1954         }
1955         up_read(&snd_ioctl_rwsem);
1956         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1957         return -ENOTTY;
1958 }
1959
1960 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1961                             size_t count, loff_t * offset)
1962 {
1963         struct snd_ctl_file *ctl;
1964         int err = 0;
1965         ssize_t result = 0;
1966
1967         ctl = file->private_data;
1968         if (snd_BUG_ON(!ctl || !ctl->card))
1969                 return -ENXIO;
1970         if (!ctl->subscribed)
1971                 return -EBADFD;
1972         if (count < sizeof(struct snd_ctl_event))
1973                 return -EINVAL;
1974         spin_lock_irq(&ctl->read_lock);
1975         while (count >= sizeof(struct snd_ctl_event)) {
1976                 struct snd_ctl_event ev;
1977                 struct snd_kctl_event *kev;
1978                 while (list_empty(&ctl->events)) {
1979                         wait_queue_entry_t wait;
1980                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1981                                 err = -EAGAIN;
1982                                 goto __end_lock;
1983                         }
1984                         init_waitqueue_entry(&wait, current);
1985                         add_wait_queue(&ctl->change_sleep, &wait);
1986                         set_current_state(TASK_INTERRUPTIBLE);
1987                         spin_unlock_irq(&ctl->read_lock);
1988                         schedule();
1989                         remove_wait_queue(&ctl->change_sleep, &wait);
1990                         if (ctl->card->shutdown)
1991                                 return -ENODEV;
1992                         if (signal_pending(current))
1993                                 return -ERESTARTSYS;
1994                         spin_lock_irq(&ctl->read_lock);
1995                 }
1996                 kev = snd_kctl_event(ctl->events.next);
1997                 ev.type = SNDRV_CTL_EVENT_ELEM;
1998                 ev.data.elem.mask = kev->mask;
1999                 ev.data.elem.id = kev->id;
2000                 list_del(&kev->list);
2001                 spin_unlock_irq(&ctl->read_lock);
2002                 kfree(kev);
2003                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
2004                         err = -EFAULT;
2005                         goto __end;
2006                 }
2007                 spin_lock_irq(&ctl->read_lock);
2008                 buffer += sizeof(struct snd_ctl_event);
2009                 count -= sizeof(struct snd_ctl_event);
2010                 result += sizeof(struct snd_ctl_event);
2011         }
2012       __end_lock:
2013         spin_unlock_irq(&ctl->read_lock);
2014       __end:
2015         return result > 0 ? result : err;
2016 }
2017
2018 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
2019 {
2020         __poll_t mask;
2021         struct snd_ctl_file *ctl;
2022
2023         ctl = file->private_data;
2024         if (!ctl->subscribed)
2025                 return 0;
2026         poll_wait(file, &ctl->change_sleep, wait);
2027
2028         mask = 0;
2029         if (!list_empty(&ctl->events))
2030                 mask |= EPOLLIN | EPOLLRDNORM;
2031
2032         return mask;
2033 }
2034
2035 /*
2036  * register the device-specific control-ioctls.
2037  * called from each device manager like pcm.c, hwdep.c, etc.
2038  */
2039 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
2040 {
2041         struct snd_kctl_ioctl *pn;
2042
2043         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
2044         if (pn == NULL)
2045                 return -ENOMEM;
2046         pn->fioctl = fcn;
2047         down_write(&snd_ioctl_rwsem);
2048         list_add_tail(&pn->list, lists);
2049         up_write(&snd_ioctl_rwsem);
2050         return 0;
2051 }
2052
2053 /**
2054  * snd_ctl_register_ioctl - register the device-specific control-ioctls
2055  * @fcn: ioctl callback function
2056  *
2057  * called from each device manager like pcm.c, hwdep.c, etc.
2058  *
2059  * Return: zero if successful, or a negative error code
2060  */
2061 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
2062 {
2063         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
2064 }
2065 EXPORT_SYMBOL(snd_ctl_register_ioctl);
2066
2067 #ifdef CONFIG_COMPAT
2068 /**
2069  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
2070  * control-ioctls
2071  * @fcn: ioctl callback function
2072  *
2073  * Return: zero if successful, or a negative error code
2074  */
2075 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2076 {
2077         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
2078 }
2079 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
2080 #endif
2081
2082 /*
2083  * de-register the device-specific control-ioctls.
2084  */
2085 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
2086                                      struct list_head *lists)
2087 {
2088         struct snd_kctl_ioctl *p;
2089
2090         if (snd_BUG_ON(!fcn))
2091                 return -EINVAL;
2092         down_write(&snd_ioctl_rwsem);
2093         list_for_each_entry(p, lists, list) {
2094                 if (p->fioctl == fcn) {
2095                         list_del(&p->list);
2096                         up_write(&snd_ioctl_rwsem);
2097                         kfree(p);
2098                         return 0;
2099                 }
2100         }
2101         up_write(&snd_ioctl_rwsem);
2102         snd_BUG();
2103         return -EINVAL;
2104 }
2105
2106 /**
2107  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
2108  * @fcn: ioctl callback function to unregister
2109  *
2110  * Return: zero if successful, or a negative error code
2111  */
2112 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
2113 {
2114         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
2115 }
2116 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
2117
2118 #ifdef CONFIG_COMPAT
2119 /**
2120  * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
2121  * 32bit control-ioctls
2122  * @fcn: ioctl callback function to unregister
2123  *
2124  * Return: zero if successful, or a negative error code
2125  */
2126 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2127 {
2128         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
2129 }
2130 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
2131 #endif
2132
2133 static int snd_ctl_fasync(int fd, struct file * file, int on)
2134 {
2135         struct snd_ctl_file *ctl;
2136
2137         ctl = file->private_data;
2138         return snd_fasync_helper(fd, file, on, &ctl->fasync);
2139 }
2140
2141 /* return the preferred subdevice number if already assigned;
2142  * otherwise return -1
2143  */
2144 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
2145 {
2146         struct snd_ctl_file *kctl;
2147         int subdevice = -1;
2148         unsigned long flags;
2149
2150         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2151         list_for_each_entry(kctl, &card->ctl_files, list) {
2152                 if (kctl->pid == task_pid(current)) {
2153                         subdevice = kctl->preferred_subdevice[type];
2154                         if (subdevice != -1)
2155                                 break;
2156                 }
2157         }
2158         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2159         return subdevice;
2160 }
2161 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
2162
2163 /*
2164  * ioctl32 compat
2165  */
2166 #ifdef CONFIG_COMPAT
2167 #include "control_compat.c"
2168 #else
2169 #define snd_ctl_ioctl_compat    NULL
2170 #endif
2171
2172 /*
2173  * control layers (audio LED etc.)
2174  */
2175
2176 /**
2177  * snd_ctl_request_layer - request to use the layer
2178  * @module_name: Name of the kernel module (NULL == build-in)
2179  *
2180  * Return: zero if successful, or an error code when the module cannot be loaded
2181  */
2182 int snd_ctl_request_layer(const char *module_name)
2183 {
2184         struct snd_ctl_layer_ops *lops;
2185
2186         if (module_name == NULL)
2187                 return 0;
2188         down_read(&snd_ctl_layer_rwsem);
2189         for (lops = snd_ctl_layer; lops; lops = lops->next)
2190                 if (strcmp(lops->module_name, module_name) == 0)
2191                         break;
2192         up_read(&snd_ctl_layer_rwsem);
2193         if (lops)
2194                 return 0;
2195         return request_module(module_name);
2196 }
2197 EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
2198
2199 /**
2200  * snd_ctl_register_layer - register new control layer
2201  * @lops: operation structure
2202  *
2203  * The new layer can track all control elements and do additional
2204  * operations on top (like audio LED handling).
2205  */
2206 void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
2207 {
2208         struct snd_card *card;
2209         int card_number;
2210
2211         down_write(&snd_ctl_layer_rwsem);
2212         lops->next = snd_ctl_layer;
2213         snd_ctl_layer = lops;
2214         up_write(&snd_ctl_layer_rwsem);
2215         for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
2216                 card = snd_card_ref(card_number);
2217                 if (card) {
2218                         down_read(&card->controls_rwsem);
2219                         lops->lregister(card);
2220                         up_read(&card->controls_rwsem);
2221                         snd_card_unref(card);
2222                 }
2223         }
2224 }
2225 EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
2226
2227 /**
2228  * snd_ctl_disconnect_layer - disconnect control layer
2229  * @lops: operation structure
2230  *
2231  * It is expected that the information about tracked cards
2232  * is freed before this call (the disconnect callback is
2233  * not called here).
2234  */
2235 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
2236 {
2237         struct snd_ctl_layer_ops *lops2, *prev_lops2;
2238
2239         down_write(&snd_ctl_layer_rwsem);
2240         for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
2241                 if (lops2 == lops) {
2242                         if (!prev_lops2)
2243                                 snd_ctl_layer = lops->next;
2244                         else
2245                                 prev_lops2->next = lops->next;
2246                         break;
2247                 }
2248                 prev_lops2 = lops2;
2249         }
2250         up_write(&snd_ctl_layer_rwsem);
2251 }
2252 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
2253
2254 /*
2255  *  INIT PART
2256  */
2257
2258 static const struct file_operations snd_ctl_f_ops =
2259 {
2260         .owner =        THIS_MODULE,
2261         .read =         snd_ctl_read,
2262         .open =         snd_ctl_open,
2263         .release =      snd_ctl_release,
2264         .llseek =       no_llseek,
2265         .poll =         snd_ctl_poll,
2266         .unlocked_ioctl =       snd_ctl_ioctl,
2267         .compat_ioctl = snd_ctl_ioctl_compat,
2268         .fasync =       snd_ctl_fasync,
2269 };
2270
2271 /*
2272  * registration of the control device
2273  */
2274 static int snd_ctl_dev_register(struct snd_device *device)
2275 {
2276         struct snd_card *card = device->device_data;
2277         struct snd_ctl_layer_ops *lops;
2278         int err;
2279
2280         err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2281                                   &snd_ctl_f_ops, card, &card->ctl_dev);
2282         if (err < 0)
2283                 return err;
2284         down_read(&card->controls_rwsem);
2285         down_read(&snd_ctl_layer_rwsem);
2286         for (lops = snd_ctl_layer; lops; lops = lops->next)
2287                 lops->lregister(card);
2288         up_read(&snd_ctl_layer_rwsem);
2289         up_read(&card->controls_rwsem);
2290         return 0;
2291 }
2292
2293 /*
2294  * disconnection of the control device
2295  */
2296 static int snd_ctl_dev_disconnect(struct snd_device *device)
2297 {
2298         struct snd_card *card = device->device_data;
2299         struct snd_ctl_file *ctl;
2300         struct snd_ctl_layer_ops *lops;
2301         unsigned long flags;
2302
2303         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2304         list_for_each_entry(ctl, &card->ctl_files, list) {
2305                 wake_up(&ctl->change_sleep);
2306                 snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
2307         }
2308         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2309
2310         down_read(&card->controls_rwsem);
2311         down_read(&snd_ctl_layer_rwsem);
2312         for (lops = snd_ctl_layer; lops; lops = lops->next)
2313                 lops->ldisconnect(card);
2314         up_read(&snd_ctl_layer_rwsem);
2315         up_read(&card->controls_rwsem);
2316
2317         return snd_unregister_device(&card->ctl_dev);
2318 }
2319
2320 /*
2321  * free all controls
2322  */
2323 static int snd_ctl_dev_free(struct snd_device *device)
2324 {
2325         struct snd_card *card = device->device_data;
2326         struct snd_kcontrol *control;
2327
2328         down_write(&card->controls_rwsem);
2329         while (!list_empty(&card->controls)) {
2330                 control = snd_kcontrol(card->controls.next);
2331                 __snd_ctl_remove(card, control, false);
2332         }
2333
2334 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
2335         xa_destroy(&card->ctl_numids);
2336         xa_destroy(&card->ctl_hash);
2337 #endif
2338         up_write(&card->controls_rwsem);
2339         put_device(&card->ctl_dev);
2340         return 0;
2341 }
2342
2343 /*
2344  * create control core:
2345  * called from init.c
2346  */
2347 int snd_ctl_create(struct snd_card *card)
2348 {
2349         static const struct snd_device_ops ops = {
2350                 .dev_free = snd_ctl_dev_free,
2351                 .dev_register = snd_ctl_dev_register,
2352                 .dev_disconnect = snd_ctl_dev_disconnect,
2353         };
2354         int err;
2355
2356         if (snd_BUG_ON(!card))
2357                 return -ENXIO;
2358         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2359                 return -ENXIO;
2360
2361         snd_device_initialize(&card->ctl_dev, card);
2362         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2363
2364         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2365         if (err < 0)
2366                 put_device(&card->ctl_dev);
2367         return err;
2368 }
2369
2370 /*
2371  * Frequently used control callbacks/helpers
2372  */
2373
2374 /**
2375  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2376  * callback with a mono channel
2377  * @kcontrol: the kcontrol instance
2378  * @uinfo: info to store
2379  *
2380  * This is a function that can be used as info callback for a standard
2381  * boolean control with a single mono channel.
2382  *
2383  * Return: Zero (always successful)
2384  */
2385 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2386                               struct snd_ctl_elem_info *uinfo)
2387 {
2388         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2389         uinfo->count = 1;
2390         uinfo->value.integer.min = 0;
2391         uinfo->value.integer.max = 1;
2392         return 0;
2393 }
2394 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2395
2396 /**
2397  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2398  * callback with stereo two channels
2399  * @kcontrol: the kcontrol instance
2400  * @uinfo: info to store
2401  *
2402  * This is a function that can be used as info callback for a standard
2403  * boolean control with stereo two channels.
2404  *
2405  * Return: Zero (always successful)
2406  */
2407 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2408                                 struct snd_ctl_elem_info *uinfo)
2409 {
2410         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2411         uinfo->count = 2;
2412         uinfo->value.integer.min = 0;
2413         uinfo->value.integer.max = 1;
2414         return 0;
2415 }
2416 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2417
2418 /**
2419  * snd_ctl_enum_info - fills the info structure for an enumerated control
2420  * @info: the structure to be filled
2421  * @channels: the number of the control's channels; often one
2422  * @items: the number of control values; also the size of @names
2423  * @names: an array containing the names of all control values
2424  *
2425  * Sets all required fields in @info to their appropriate values.
2426  * If the control's accessibility is not the default (readable and writable),
2427  * the caller has to fill @info->access.
2428  *
2429  * Return: Zero (always successful)
2430  */
2431 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2432                       unsigned int items, const char *const names[])
2433 {
2434         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2435         info->count = channels;
2436         info->value.enumerated.items = items;
2437         if (!items)
2438                 return 0;
2439         if (info->value.enumerated.item >= items)
2440                 info->value.enumerated.item = items - 1;
2441         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2442              "ALSA: too long item name '%s'\n",
2443              names[info->value.enumerated.item]);
2444         strscpy(info->value.enumerated.name,
2445                 names[info->value.enumerated.item],
2446                 sizeof(info->value.enumerated.name));
2447         return 0;
2448 }
2449 EXPORT_SYMBOL(snd_ctl_enum_info);