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