sound/core/control.c

   1 /*
   2  *  Routines for driver control interface
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/threads.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/time.h>
  28 #include <sound/core.h>
  29 #include <sound/minors.h>
  30 #include <sound/info.h>
  31 #include <sound/control.h>
  32
  33 /* max number of user-defined controls */
  34 #define MAX_USER_CONTROLS       32
  35 #define MAX_CONTROL_COUNT       1028
  36
  37 struct snd_kctl_ioctl {
  38         struct list_head list;          /* list of all ioctls */
  39         snd_kctl_ioctl_func_t fioctl;
  40 };
  41
  42 static DECLARE_RWSEM(snd_ioctl_rwsem);
  43 static LIST_HEAD(snd_control_ioctls);
  44 #ifdef CONFIG_COMPAT
  45 static LIST_HEAD(snd_control_compat_ioctls);
  46 #endif
  47
  48 static int snd_ctl_open(struct inode *inode, struct file *file)
  49 {
  50         unsigned long flags;
  51         struct snd_card *card;
  52         struct snd_ctl_file *ctl;
  53         int i, err;
  54
  55         err = nonseekable_open(inode, file);
  56         if (err < 0)
  57                 return err;
  58
  59         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  60         if (!card) {
  61                 err = -ENODEV;
  62                 goto __error1;
  63         }
  64         err = snd_card_file_add(card, file);
  65         if (err < 0) {
  66                 err = -ENODEV;
  67                 goto __error1;
  68         }
  69         if (!try_module_get(card->module)) {
  70                 err = -EFAULT;
  71                 goto __error2;
  72         }
  73         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  74         if (ctl == NULL) {
  75                 err = -ENOMEM;
  76                 goto __error;
  77         }
  78         INIT_LIST_HEAD(&ctl->events);
  79         init_waitqueue_head(&ctl->change_sleep);
  80         spin_lock_init(&ctl->read_lock);
  81         ctl->card = card;
  82         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  83                 ctl->preferred_subdevice[i] = -1;
  84         ctl->pid = get_pid(task_pid(current));
  85         file->private_data = ctl;
  86         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  87         list_add_tail(&ctl->list, &card->ctl_files);
  88         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  89         snd_card_unref(card);
  90         return 0;
  91
  92       __error:
  93         module_put(card->module);
  94       __error2:
  95         snd_card_file_remove(card, file);
  96       __error1:
  97         if (card)
  98                 snd_card_unref(card);
  99         return err;
 100 }
 101
 102 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 103 {
 104         unsigned long flags;
 105         struct snd_kctl_event *cread;
 106
 107         spin_lock_irqsave(&ctl->read_lock, flags);
 108         while (!list_empty(&ctl->events)) {
 109                 cread = snd_kctl_event(ctl->events.next);
 110                 list_del(&cread->list);
 111                 kfree(cread);
 112         }
 113         spin_unlock_irqrestore(&ctl->read_lock, flags);
 114 }
 115
 116 static int snd_ctl_release(struct inode *inode, struct file *file)
 117 {
 118         unsigned long flags;
 119         struct snd_card *card;
 120         struct snd_ctl_file *ctl;
 121         struct snd_kcontrol *control;
 122         unsigned int idx;
 123
 124         ctl = file->private_data;
 125         file->private_data = NULL;
 126         card = ctl->card;
 127         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 128         list_del(&ctl->list);
 129         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 130         down_write(&card->controls_rwsem);
 131         list_for_each_entry(control, &card->controls, list)
 132                 for (idx = 0; idx < control->count; idx++)
 133                         if (control->vd[idx].owner == ctl)
 134                                 control->vd[idx].owner = NULL;
 135         up_write(&card->controls_rwsem);
 136         snd_ctl_empty_read_queue(ctl);
 137         put_pid(ctl->pid);
 138         kfree(ctl);
 139         module_put(card->module);
 140         snd_card_file_remove(card, file);
 141         return 0;
 142 }
 143
 144 /**
 145  * snd_ctl_notify - Send notification to user-space for a control change
 146  * @card: the card to send notification
 147  * @mask: the event mask, SNDRV_CTL_EVENT_*
 148  * @id: the ctl element id to send notification
 149  *
 150  * This function adds an event record with the given id and mask, appends
 151  * to the list and wakes up the user-space for notification.  This can be
 152  * called in the atomic context.
 153  */
 154 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 155                     struct snd_ctl_elem_id *id)
 156 {
 157         unsigned long flags;
 158         struct snd_ctl_file *ctl;
 159         struct snd_kctl_event *ev;
 160
 161         if (snd_BUG_ON(!card || !id))
 162                 return;
 163         read_lock(&card->ctl_files_rwlock);
 164 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 165         card->mixer_oss_change_count++;
 166 #endif
 167         list_for_each_entry(ctl, &card->ctl_files, list) {
 168                 if (!ctl->subscribed)
 169                         continue;
 170                 spin_lock_irqsave(&ctl->read_lock, flags);
 171                 list_for_each_entry(ev, &ctl->events, list) {
 172                         if (ev->id.numid == id->numid) {
 173                                 ev->mask |= mask;
 174                                 goto _found;
 175                         }
 176                 }
 177                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 178                 if (ev) {
 179                         ev->id = *id;
 180                         ev->mask = mask;
 181                         list_add_tail(&ev->list, &ctl->events);
 182                 } else {
 183                         dev_err(card->dev, "No memory available to allocate event\n");
 184                 }
 185         _found:
 186                 wake_up(&ctl->change_sleep);
 187                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 188                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 189         }
 190         read_unlock(&card->ctl_files_rwlock);
 191 }
 192 EXPORT_SYMBOL(snd_ctl_notify);
 193
 194 /**
 195  * snd_ctl_new - create a new control instance with some elements
 196  * @kctl: the pointer to store new control instance
 197  * @count: the number of elements in this control
 198  * @access: the default access flags for elements in this control
 199  * @file: given when locking these elements
 200  *
 201  * Allocates a memory object for a new control instance. The instance has
 202  * elements as many as the given number (@count). Each element has given
 203  * access permissions (@access). Each element is locked when @file is given.
 204  *
 205  * Return: 0 on success, error code on failure
 206  */
 207 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 208                        unsigned int access, struct snd_ctl_file *file)
 209 {
 210         unsigned int size;
 211         unsigned int idx;
 212
 213         if (count == 0 || count > MAX_CONTROL_COUNT)
 214                 return -EINVAL;
 215
 216         size  = sizeof(struct snd_kcontrol);
 217         size += sizeof(struct snd_kcontrol_volatile) * count;
 218
 219         *kctl = kzalloc(size, GFP_KERNEL);
 220         if (!*kctl)
 221                 return -ENOMEM;
 222
 223         for (idx = 0; idx < count; idx++) {
 224                 (*kctl)->vd[idx].access = access;
 225                 (*kctl)->vd[idx].owner = file;
 226         }
 227         (*kctl)->count = count;
 228
 229         return 0;
 230 }
 231
 232 /**
 233  * snd_ctl_new1 - create a control instance from the template
 234  * @ncontrol: the initialization record
 235  * @private_data: the private data to set
 236  *
 237  * Allocates a new struct snd_kcontrol instance and initialize from the given
 238  * template.  When the access field of ncontrol is 0, it's assumed as
 239  * READWRITE access. When the count field is 0, it's assumes as one.
 240  *
 241  * Return: The pointer of the newly generated instance, or %NULL on failure.
 242  */
 243 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 244                                   void *private_data)
 245 {
 246         struct snd_kcontrol *kctl;
 247         unsigned int count;
 248         unsigned int access;
 249         int err;
 250
 251         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 252                 return NULL;
 253
 254         count = ncontrol->count;
 255         if (count == 0)
 256                 count = 1;
 257
 258         access = ncontrol->access;
 259         if (access == 0)
 260                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 261         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 262                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 263                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 264                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 265                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 266                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
 267
 268         err = snd_ctl_new(&kctl, count, access, NULL);
 269         if (err < 0)
 270                 return NULL;
 271
 272         /* The 'numid' member is decided when calling snd_ctl_add(). */
 273         kctl->id.iface = ncontrol->iface;
 274         kctl->id.device = ncontrol->device;
 275         kctl->id.subdevice = ncontrol->subdevice;
 276         if (ncontrol->name) {
 277                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 278                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 279                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 280                                 ncontrol->name, kctl->id.name);
 281         }
 282         kctl->id.index = ncontrol->index;
 283
 284         kctl->info = ncontrol->info;
 285         kctl->get = ncontrol->get;
 286         kctl->put = ncontrol->put;
 287         kctl->tlv.p = ncontrol->tlv.p;
 288
 289         kctl->private_value = ncontrol->private_value;
 290         kctl->private_data = private_data;
 291
 292         return kctl;
 293 }
 294 EXPORT_SYMBOL(snd_ctl_new1);
 295
 296 /**
 297  * snd_ctl_free_one - release the control instance
 298  * @kcontrol: the control instance
 299  *
 300  * Releases the control instance created via snd_ctl_new()
 301  * or snd_ctl_new1().
 302  * Don't call this after the control was added to the card.
 303  */
 304 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 305 {
 306         if (kcontrol) {
 307                 if (kcontrol->private_free)
 308                         kcontrol->private_free(kcontrol);
 309                 kfree(kcontrol);
 310         }
 311 }
 312 EXPORT_SYMBOL(snd_ctl_free_one);
 313
 314 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 315                                           unsigned int count)
 316 {
 317         struct snd_kcontrol *kctl;
 318
 319         /* Make sure that the ids assigned to the control do not wrap around */
 320         if (card->last_numid >= UINT_MAX - count)
 321                 card->last_numid = 0;
 322
 323         list_for_each_entry(kctl, &card->controls, list) {
 324                 if (kctl->id.numid < card->last_numid + 1 + count &&
 325                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 326                         card->last_numid = kctl->id.numid + kctl->count - 1;
 327                         return true;
 328                 }
 329         }
 330         return false;
 331 }
 332
 333 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 334 {
 335         unsigned int iter = 100000;
 336
 337         while (snd_ctl_remove_numid_conflict(card, count)) {
 338                 if (--iter == 0) {
 339                         /* this situation is very unlikely */
 340                         dev_err(card->dev, "unable to allocate new control numid\n");
 341                         return -ENOMEM;
 342                 }
 343         }
 344         return 0;
 345 }
 346
 347 /**
 348  * snd_ctl_add - add the control instance to the card
 349  * @card: the card instance
 350  * @kcontrol: the control instance to add
 351  *
 352  * Adds the control instance created via snd_ctl_new() or
 353  * snd_ctl_new1() to the given card. Assigns also an unique
 354  * numid used for fast search.
 355  *
 356  * It frees automatically the control which cannot be added.
 357  *
 358  * Return: Zero if successful, or a negative error code on failure.
 359  *
 360  */
 361 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 362 {
 363         struct snd_ctl_elem_id id;
 364         unsigned int idx;
 365         unsigned int count;
 366         int err = -EINVAL;
 367
 368         if (! kcontrol)
 369                 return err;
 370         if (snd_BUG_ON(!card || !kcontrol->info))
 371                 goto error;
 372         id = kcontrol->id;
 373         if (id.index > UINT_MAX - kcontrol->count)
 374                 goto error;
 375
 376         down_write(&card->controls_rwsem);
 377         if (snd_ctl_find_id(card, &id)) {
 378                 up_write(&card->controls_rwsem);
 379                 dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n",
 380                                         id.iface,
 381                                         id.device,
 382                                         id.subdevice,
 383                                         id.name,
 384                                         id.index);
 385                 err = -EBUSY;
 386                 goto error;
 387         }
 388         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 389                 up_write(&card->controls_rwsem);
 390                 err = -ENOMEM;
 391                 goto error;
 392         }
 393         list_add_tail(&kcontrol->list, &card->controls);
 394         card->controls_count += kcontrol->count;
 395         kcontrol->id.numid = card->last_numid + 1;
 396         card->last_numid += kcontrol->count;
 397         id = kcontrol->id;
 398         count = kcontrol->count;
 399         up_write(&card->controls_rwsem);
 400         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 401                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 402         return 0;
 403
 404  error:
 405         snd_ctl_free_one(kcontrol);
 406         return err;
 407 }
 408 EXPORT_SYMBOL(snd_ctl_add);
 409
 410 /**
 411  * snd_ctl_replace - replace the control instance of the card
 412  * @card: the card instance
 413  * @kcontrol: the control instance to replace
 414  * @add_on_replace: add the control if not already added
 415  *
 416  * Replaces the given control.  If the given control does not exist
 417  * and the add_on_replace flag is set, the control is added.  If the
 418  * control exists, it is destroyed first.
 419  *
 420  * It frees automatically the control which cannot be added or replaced.
 421  *
 422  * Return: Zero if successful, or a negative error code on failure.
 423  */
 424 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 425                     bool add_on_replace)
 426 {
 427         struct snd_ctl_elem_id id;
 428         unsigned int count;
 429         unsigned int idx;
 430         struct snd_kcontrol *old;
 431         int ret;
 432
 433         if (!kcontrol)
 434                 return -EINVAL;
 435         if (snd_BUG_ON(!card || !kcontrol->info)) {
 436                 ret = -EINVAL;
 437                 goto error;
 438         }
 439         id = kcontrol->id;
 440         down_write(&card->controls_rwsem);
 441         old = snd_ctl_find_id(card, &id);
 442         if (!old) {
 443                 if (add_on_replace)
 444                         goto add;
 445                 up_write(&card->controls_rwsem);
 446                 ret = -EINVAL;
 447                 goto error;
 448         }
 449         ret = snd_ctl_remove(card, old);
 450         if (ret < 0) {
 451                 up_write(&card->controls_rwsem);
 452                 goto error;
 453         }
 454 add:
 455         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 456                 up_write(&card->controls_rwsem);
 457                 ret = -ENOMEM;
 458                 goto error;
 459         }
 460         list_add_tail(&kcontrol->list, &card->controls);
 461         card->controls_count += kcontrol->count;
 462         kcontrol->id.numid = card->last_numid + 1;
 463         card->last_numid += kcontrol->count;
 464         id = kcontrol->id;
 465         count = kcontrol->count;
 466         up_write(&card->controls_rwsem);
 467         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 468                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 469         return 0;
 470
 471 error:
 472         snd_ctl_free_one(kcontrol);
 473         return ret;
 474 }
 475 EXPORT_SYMBOL(snd_ctl_replace);
 476
 477 /**
 478  * snd_ctl_remove - remove the control from the card and release it
 479  * @card: the card instance
 480  * @kcontrol: the control instance to remove
 481  *
 482  * Removes the control from the card and then releases the instance.
 483  * You don't need to call snd_ctl_free_one(). You must be in
 484  * the write lock - down_write(&card->controls_rwsem).
 485  *
 486  * Return: 0 if successful, or a negative error code on failure.
 487  */
 488 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 489 {
 490         struct snd_ctl_elem_id id;
 491         unsigned int idx;
 492
 493         if (snd_BUG_ON(!card || !kcontrol))
 494                 return -EINVAL;
 495         list_del(&kcontrol->list);
 496         card->controls_count -= kcontrol->count;
 497         id = kcontrol->id;
 498         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 499                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 500         snd_ctl_free_one(kcontrol);
 501         return 0;
 502 }
 503 EXPORT_SYMBOL(snd_ctl_remove);
 504
 505 /**
 506  * snd_ctl_remove_id - remove the control of the given id and release it
 507  * @card: the card instance
 508  * @id: the control id to remove
 509  *
 510  * Finds the control instance with the given id, removes it from the
 511  * card list and releases it.
 512  *
 513  * Return: 0 if successful, or a negative error code on failure.
 514  */
 515 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 516 {
 517         struct snd_kcontrol *kctl;
 518         int ret;
 519
 520         down_write(&card->controls_rwsem);
 521         kctl = snd_ctl_find_id(card, id);
 522         if (kctl == NULL) {
 523                 up_write(&card->controls_rwsem);
 524                 return -ENOENT;
 525         }
 526         ret = snd_ctl_remove(card, kctl);
 527         up_write(&card->controls_rwsem);
 528         return ret;
 529 }
 530 EXPORT_SYMBOL(snd_ctl_remove_id);
 531
 532 /**
 533  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 534  * @file: active control handle
 535  * @id: the control id to remove
 536  *
 537  * Finds the control instance with the given id, removes it from the
 538  * card list and releases it.
 539  *
 540  * Return: 0 if successful, or a negative error code on failure.
 541  */
 542 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 543                                    struct snd_ctl_elem_id *id)
 544 {
 545         struct snd_card *card = file->card;
 546         struct snd_kcontrol *kctl;
 547         int idx, ret;
 548
 549         down_write(&card->controls_rwsem);
 550         kctl = snd_ctl_find_id(card, id);
 551         if (kctl == NULL) {
 552                 ret = -ENOENT;
 553                 goto error;
 554         }
 555         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 556                 ret = -EINVAL;
 557                 goto error;
 558         }
 559         for (idx = 0; idx < kctl->count; idx++)
 560                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 561                         ret = -EBUSY;
 562                         goto error;
 563                 }
 564         ret = snd_ctl_remove(card, kctl);
 565         if (ret < 0)
 566                 goto error;
 567         card->user_ctl_count--;
 568 error:
 569         up_write(&card->controls_rwsem);
 570         return ret;
 571 }
 572
 573 /**
 574  * snd_ctl_activate_id - activate/inactivate the control of the given id
 575  * @card: the card instance
 576  * @id: the control id to activate/inactivate
 577  * @active: non-zero to activate
 578  *
 579  * Finds the control instance with the given id, and activate or
 580  * inactivate the control together with notification, if changed.
 581  * The given ID data is filled with full information.
 582  *
 583  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 584  */
 585 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 586                         int active)
 587 {
 588         struct snd_kcontrol *kctl;
 589         struct snd_kcontrol_volatile *vd;
 590         unsigned int index_offset;
 591         int ret;
 592
 593         down_write(&card->controls_rwsem);
 594         kctl = snd_ctl_find_id(card, id);
 595         if (kctl == NULL) {
 596                 ret = -ENOENT;
 597                 goto unlock;
 598         }
 599         index_offset = snd_ctl_get_ioff(kctl, id);
 600         vd = &kctl->vd[index_offset];
 601         ret = 0;
 602         if (active) {
 603                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 604                         goto unlock;
 605                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 606         } else {
 607                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 608                         goto unlock;
 609                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 610         }
 611         snd_ctl_build_ioff(id, kctl, index_offset);
 612         ret = 1;
 613  unlock:
 614         up_write(&card->controls_rwsem);
 615         if (ret > 0)
 616                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 617         return ret;
 618 }
 619 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 620
 621 /**
 622  * snd_ctl_rename_id - replace the id of a control on the card
 623  * @card: the card instance
 624  * @src_id: the old id
 625  * @dst_id: the new id
 626  *
 627  * Finds the control with the old id from the card, and replaces the
 628  * id with the new one.
 629  *
 630  * Return: Zero if successful, or a negative error code on failure.
 631  */
 632 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 633                       struct snd_ctl_elem_id *dst_id)
 634 {
 635         struct snd_kcontrol *kctl;
 636
 637         down_write(&card->controls_rwsem);
 638         kctl = snd_ctl_find_id(card, src_id);
 639         if (kctl == NULL) {
 640                 up_write(&card->controls_rwsem);
 641                 return -ENOENT;
 642         }
 643         kctl->id = *dst_id;
 644         kctl->id.numid = card->last_numid + 1;
 645         card->last_numid += kctl->count;
 646         up_write(&card->controls_rwsem);
 647         return 0;
 648 }
 649 EXPORT_SYMBOL(snd_ctl_rename_id);
 650
 651 /**
 652  * snd_ctl_find_numid - find the control instance with the given number-id
 653  * @card: the card instance
 654  * @numid: the number-id to search
 655  *
 656  * Finds the control instance with the given number-id from the card.
 657  *
 658  * The caller must down card->controls_rwsem before calling this function
 659  * (if the race condition can happen).
 660  *
 661  * Return: The pointer of the instance if found, or %NULL if not.
 662  *
 663  */
 664 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 665 {
 666         struct snd_kcontrol *kctl;
 667
 668         if (snd_BUG_ON(!card || !numid))
 669                 return NULL;
 670         list_for_each_entry(kctl, &card->controls, list) {
 671                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 672                         return kctl;
 673         }
 674         return NULL;
 675 }
 676 EXPORT_SYMBOL(snd_ctl_find_numid);
 677
 678 /**
 679  * snd_ctl_find_id - find the control instance with the given id
 680  * @card: the card instance
 681  * @id: the id to search
 682  *
 683  * Finds the control instance with the given id from the card.
 684  *
 685  * The caller must down card->controls_rwsem before calling this function
 686  * (if the race condition can happen).
 687  *
 688  * Return: The pointer of the instance if found, or %NULL if not.
 689  *
 690  */
 691 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 692                                      struct snd_ctl_elem_id *id)
 693 {
 694         struct snd_kcontrol *kctl;
 695
 696         if (snd_BUG_ON(!card || !id))
 697                 return NULL;
 698         if (id->numid != 0)
 699                 return snd_ctl_find_numid(card, id->numid);
 700         list_for_each_entry(kctl, &card->controls, list) {
 701                 if (kctl->id.iface != id->iface)
 702                         continue;
 703                 if (kctl->id.device != id->device)
 704                         continue;
 705                 if (kctl->id.subdevice != id->subdevice)
 706                         continue;
 707                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 708                         continue;
 709                 if (kctl->id.index > id->index)
 710                         continue;
 711                 if (kctl->id.index + kctl->count <= id->index)
 712                         continue;
 713                 return kctl;
 714         }
 715         return NULL;
 716 }
 717 EXPORT_SYMBOL(snd_ctl_find_id);
 718
 719 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 720                              unsigned int cmd, void __user *arg)
 721 {
 722         struct snd_ctl_card_info *info;
 723
 724         info = kzalloc(sizeof(*info), GFP_KERNEL);
 725         if (! info)
 726                 return -ENOMEM;
 727         down_read(&snd_ioctl_rwsem);
 728         info->card = card->number;
 729         strlcpy(info->id, card->id, sizeof(info->id));
 730         strlcpy(info->driver, card->driver, sizeof(info->driver));
 731         strlcpy(info->name, card->shortname, sizeof(info->name));
 732         strlcpy(info->longname, card->longname, sizeof(info->longname));
 733         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 734         strlcpy(info->components, card->components, sizeof(info->components));
 735         up_read(&snd_ioctl_rwsem);
 736         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 737                 kfree(info);
 738                 return -EFAULT;
 739         }
 740         kfree(info);
 741         return 0;
 742 }
 743
 744 static int snd_ctl_elem_list(struct snd_card *card,
 745                              struct snd_ctl_elem_list __user *_list)
 746 {
 747         struct list_head *plist;
 748         struct snd_ctl_elem_list list;
 749         struct snd_kcontrol *kctl;
 750         struct snd_ctl_elem_id *dst, *id;
 751         unsigned int offset, space, jidx;
 752
 753         if (copy_from_user(&list, _list, sizeof(list)))
 754                 return -EFAULT;
 755         offset = list.offset;
 756         space = list.space;
 757         /* try limit maximum space */
 758         if (space > 16384)
 759                 return -ENOMEM;
 760         if (space > 0) {
 761                 /* allocate temporary buffer for atomic operation */
 762                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 763                 if (dst == NULL)
 764                         return -ENOMEM;
 765                 down_read(&card->controls_rwsem);
 766                 list.count = card->controls_count;
 767                 plist = card->controls.next;
 768                 while (plist != &card->controls) {
 769                         if (offset == 0)
 770                                 break;
 771                         kctl = snd_kcontrol(plist);
 772                         if (offset < kctl->count)
 773                                 break;
 774                         offset -= kctl->count;
 775                         plist = plist->next;
 776                 }
 777                 list.used = 0;
 778                 id = dst;
 779                 while (space > 0 && plist != &card->controls) {
 780                         kctl = snd_kcontrol(plist);
 781                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 782                                 snd_ctl_build_ioff(id, kctl, jidx);
 783                                 id++;
 784                                 space--;
 785                                 list.used++;
 786                         }
 787                         plist = plist->next;
 788                         offset = 0;
 789                 }
 790                 up_read(&card->controls_rwsem);
 791                 if (list.used > 0 &&
 792                     copy_to_user(list.pids, dst,
 793                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 794                         vfree(dst);
 795                         return -EFAULT;
 796                 }
 797                 vfree(dst);
 798         } else {
 799                 down_read(&card->controls_rwsem);
 800                 list.count = card->controls_count;
 801                 up_read(&card->controls_rwsem);
 802         }
 803         if (copy_to_user(_list, &list, sizeof(list)))
 804                 return -EFAULT;
 805         return 0;
 806 }
 807
 808 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 809                              struct snd_ctl_elem_info *info)
 810 {
 811         struct snd_card *card = ctl->card;
 812         struct snd_kcontrol *kctl;
 813         struct snd_kcontrol_volatile *vd;
 814         unsigned int index_offset;
 815         int result;
 816
 817         down_read(&card->controls_rwsem);
 818         kctl = snd_ctl_find_id(card, &info->id);
 819         if (kctl == NULL) {
 820                 up_read(&card->controls_rwsem);
 821                 return -ENOENT;
 822         }
 823 #ifdef CONFIG_SND_DEBUG
 824         info->access = 0;
 825 #endif
 826         result = kctl->info(kctl, info);
 827         if (result >= 0) {
 828                 snd_BUG_ON(info->access);
 829                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 830                 vd = &kctl->vd[index_offset];
 831                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 832                 info->access = vd->access;
 833                 if (vd->owner) {
 834                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 835                         if (vd->owner == ctl)
 836                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 837                         info->owner = pid_vnr(vd->owner->pid);
 838                 } else {
 839                         info->owner = -1;
 840                 }
 841         }
 842         up_read(&card->controls_rwsem);
 843         return result;
 844 }
 845
 846 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 847                                   struct snd_ctl_elem_info __user *_info)
 848 {
 849         struct snd_ctl_elem_info info;
 850         int result;
 851
 852         if (copy_from_user(&info, _info, sizeof(info)))
 853                 return -EFAULT;
 854         snd_power_lock(ctl->card);
 855         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 856         if (result >= 0)
 857                 result = snd_ctl_elem_info(ctl, &info);
 858         snd_power_unlock(ctl->card);
 859         if (result >= 0)
 860                 if (copy_to_user(_info, &info, sizeof(info)))
 861                         return -EFAULT;
 862         return result;
 863 }
 864
 865 static int snd_ctl_elem_read(struct snd_card *card,
 866                              struct snd_ctl_elem_value *control)
 867 {
 868         struct snd_kcontrol *kctl;
 869         struct snd_kcontrol_volatile *vd;
 870         unsigned int index_offset;
 871         int result;
 872
 873         down_read(&card->controls_rwsem);
 874         kctl = snd_ctl_find_id(card, &control->id);
 875         if (kctl == NULL) {
 876                 result = -ENOENT;
 877         } else {
 878                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 879                 vd = &kctl->vd[index_offset];
 880                 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
 881                     kctl->get != NULL) {
 882                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 883                         result = kctl->get(kctl, control);
 884                 } else
 885                         result = -EPERM;
 886         }
 887         up_read(&card->controls_rwsem);
 888         return result;
 889 }
 890
 891 static int snd_ctl_elem_read_user(struct snd_card *card,
 892                                   struct snd_ctl_elem_value __user *_control)
 893 {
 894         struct snd_ctl_elem_value *control;
 895         int result;
 896
 897         control = memdup_user(_control, sizeof(*control));
 898         if (IS_ERR(control))
 899                 return PTR_ERR(control);
 900
 901         snd_power_lock(card);
 902         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 903         if (result >= 0)
 904                 result = snd_ctl_elem_read(card, control);
 905         snd_power_unlock(card);
 906         if (result >= 0)
 907                 if (copy_to_user(_control, control, sizeof(*control)))
 908                         result = -EFAULT;
 909         kfree(control);
 910         return result;
 911 }
 912
 913 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 914                               struct snd_ctl_elem_value *control)
 915 {
 916         struct snd_kcontrol *kctl;
 917         struct snd_kcontrol_volatile *vd;
 918         unsigned int index_offset;
 919         int result;
 920
 921         down_read(&card->controls_rwsem);
 922         kctl = snd_ctl_find_id(card, &control->id);
 923         if (kctl == NULL) {
 924                 result = -ENOENT;
 925         } else {
 926                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 927                 vd = &kctl->vd[index_offset];
 928                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 929                     kctl->put == NULL ||
 930                     (file && vd->owner && vd->owner != file)) {
 931                         result = -EPERM;
 932                 } else {
 933                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 934                         result = kctl->put(kctl, control);
 935                 }
 936                 if (result > 0) {
 937                         struct snd_ctl_elem_id id = control->id;
 938                         up_read(&card->controls_rwsem);
 939                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 940                         return 0;
 941                 }
 942         }
 943         up_read(&card->controls_rwsem);
 944         return result;
 945 }
 946
 947 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 948                                    struct snd_ctl_elem_value __user *_control)
 949 {
 950         struct snd_ctl_elem_value *control;
 951         struct snd_card *card;
 952         int result;
 953
 954         control = memdup_user(_control, sizeof(*control));
 955         if (IS_ERR(control))
 956                 return PTR_ERR(control);
 957
 958         card = file->card;
 959         snd_power_lock(card);
 960         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 961         if (result >= 0)
 962                 result = snd_ctl_elem_write(card, file, control);
 963         snd_power_unlock(card);
 964         if (result >= 0)
 965                 if (copy_to_user(_control, control, sizeof(*control)))
 966                         result = -EFAULT;
 967         kfree(control);
 968         return result;
 969 }
 970
 971 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 972                              struct snd_ctl_elem_id __user *_id)
 973 {
 974         struct snd_card *card = file->card;
 975         struct snd_ctl_elem_id id;
 976         struct snd_kcontrol *kctl;
 977         struct snd_kcontrol_volatile *vd;
 978         int result;
 979
 980         if (copy_from_user(&id, _id, sizeof(id)))
 981                 return -EFAULT;
 982         down_write(&card->controls_rwsem);
 983         kctl = snd_ctl_find_id(card, &id);
 984         if (kctl == NULL) {
 985                 result = -ENOENT;
 986         } else {
 987                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 988                 if (vd->owner != NULL)
 989                         result = -EBUSY;
 990                 else {
 991                         vd->owner = file;
 992                         result = 0;
 993                 }
 994         }
 995         up_write(&card->controls_rwsem);
 996         return result;
 997 }
 998
 999 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1000                                struct snd_ctl_elem_id __user *_id)
1001 {
1002         struct snd_card *card = file->card;
1003         struct snd_ctl_elem_id id;
1004         struct snd_kcontrol *kctl;
1005         struct snd_kcontrol_volatile *vd;
1006         int result;
1007
1008         if (copy_from_user(&id, _id, sizeof(id)))
1009                 return -EFAULT;
1010         down_write(&card->controls_rwsem);
1011         kctl = snd_ctl_find_id(card, &id);
1012         if (kctl == NULL) {
1013                 result = -ENOENT;
1014         } else {
1015                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1016                 if (vd->owner == NULL)
1017                         result = -EINVAL;
1018                 else if (vd->owner != file)
1019                         result = -EPERM;
1020                 else {
1021                         vd->owner = NULL;
1022                         result = 0;
1023                 }
1024         }
1025         up_write(&card->controls_rwsem);
1026         return result;
1027 }
1028
1029 struct user_element {
1030         struct snd_ctl_elem_info info;
1031         struct snd_card *card;
1032         void *elem_data;                /* element data */
1033         unsigned long elem_data_size;   /* size of element data in bytes */
1034         void *tlv_data;                 /* TLV data */
1035         unsigned long tlv_data_size;    /* TLV data size */
1036         void *priv_data;                /* private data (like strings for enumerated type) */
1037 };
1038
1039 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1040                                   struct snd_ctl_elem_info *uinfo)
1041 {
1042         struct user_element *ue = kcontrol->private_data;
1043         unsigned int offset;
1044
1045         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1046         *uinfo = ue->info;
1047         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1048
1049         return 0;
1050 }
1051
1052 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1053                                        struct snd_ctl_elem_info *uinfo)
1054 {
1055         struct user_element *ue = kcontrol->private_data;
1056         const char *names;
1057         unsigned int item;
1058         unsigned int offset;
1059
1060         item = uinfo->value.enumerated.item;
1061
1062         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1063         *uinfo = ue->info;
1064         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1065
1066         item = min(item, uinfo->value.enumerated.items - 1);
1067         uinfo->value.enumerated.item = item;
1068
1069         names = ue->priv_data;
1070         for (; item > 0; --item)
1071                 names += strlen(names) + 1;
1072         strcpy(uinfo->value.enumerated.name, names);
1073
1074         return 0;
1075 }
1076
1077 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1078                                  struct snd_ctl_elem_value *ucontrol)
1079 {
1080         struct user_element *ue = kcontrol->private_data;
1081
1082         mutex_lock(&ue->card->user_ctl_lock);
1083         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1084         mutex_unlock(&ue->card->user_ctl_lock);
1085         return 0;
1086 }
1087
1088 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1089                                  struct snd_ctl_elem_value *ucontrol)
1090 {
1091         int change;
1092         struct user_element *ue = kcontrol->private_data;
1093
1094         mutex_lock(&ue->card->user_ctl_lock);
1095         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1096         if (change)
1097                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1098         mutex_unlock(&ue->card->user_ctl_lock);
1099         return change;
1100 }
1101
1102 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1103                                  int op_flag,
1104                                  unsigned int size,
1105                                  unsigned int __user *tlv)
1106 {
1107         struct user_element *ue = kcontrol->private_data;
1108         int change = 0;
1109         void *new_data;
1110
1111         if (op_flag == SNDRV_CTL_TLV_OP_WRITE) {
1112                 if (size > 1024 * 128)  /* sane value */
1113                         return -EINVAL;
1114
1115                 new_data = memdup_user(tlv, size);
1116                 if (IS_ERR(new_data))
1117                         return PTR_ERR(new_data);
1118                 mutex_lock(&ue->card->user_ctl_lock);
1119                 change = ue->tlv_data_size != size;
1120                 if (!change)
1121                         change = memcmp(ue->tlv_data, new_data, size);
1122                 kfree(ue->tlv_data);
1123                 ue->tlv_data = new_data;
1124                 ue->tlv_data_size = size;
1125                 mutex_unlock(&ue->card->user_ctl_lock);
1126         } else {
1127                 int ret = 0;
1128
1129                 mutex_lock(&ue->card->user_ctl_lock);
1130                 if (!ue->tlv_data_size || !ue->tlv_data) {
1131                         ret = -ENXIO;
1132                         goto err_unlock;
1133                 }
1134                 if (size < ue->tlv_data_size) {
1135                         ret = -ENOSPC;
1136                         goto err_unlock;
1137                 }
1138                 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1139                         ret = -EFAULT;
1140 err_unlock:
1141                 mutex_unlock(&ue->card->user_ctl_lock);
1142                 if (ret)
1143                         return ret;
1144         }
1145         return change;
1146 }
1147
1148 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1149 {
1150         char *names, *p;
1151         size_t buf_len, name_len;
1152         unsigned int i;
1153         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1154
1155         if (ue->info.value.enumerated.names_length > 64 * 1024)
1156                 return -EINVAL;
1157
1158         names = memdup_user((const void __user *)user_ptrval,
1159                 ue->info.value.enumerated.names_length);
1160         if (IS_ERR(names))
1161                 return PTR_ERR(names);
1162
1163         /* check that there are enough valid names */
1164         buf_len = ue->info.value.enumerated.names_length;
1165         p = names;
1166         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1167                 name_len = strnlen(p, buf_len);
1168                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1169                         kfree(names);
1170                         return -EINVAL;
1171                 }
1172                 p += name_len + 1;
1173                 buf_len -= name_len + 1;
1174         }
1175
1176         ue->priv_data = names;
1177         ue->info.value.enumerated.names_ptr = 0;
1178
1179         return 0;
1180 }
1181
1182 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1183 {
1184         struct user_element *ue = kcontrol->private_data;
1185
1186         kfree(ue->tlv_data);
1187         kfree(ue->priv_data);
1188         kfree(ue);
1189 }
1190
1191 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1192                             struct snd_ctl_elem_info *info, int replace)
1193 {
1194         /* The capacity of struct snd_ctl_elem_value.value.*/
1195         static const unsigned int value_sizes[] = {
1196                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
1197                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
1198                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1199                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
1200                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
1201                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1202         };
1203         static const unsigned int max_value_counts[] = {
1204                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
1205                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
1206                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1207                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
1208                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
1209                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1210         };
1211         struct snd_card *card = file->card;
1212         struct snd_kcontrol *kctl;
1213         unsigned int count;
1214         unsigned int access;
1215         long private_size;
1216         struct user_element *ue;
1217         unsigned int offset;
1218         int err;
1219
1220         if (!*info->id.name)
1221                 return -EINVAL;
1222         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1223                 return -EINVAL;
1224
1225         /* Delete a control to replace them if needed. */
1226         if (replace) {
1227                 info->id.numid = 0;
1228                 err = snd_ctl_remove_user_ctl(file, &info->id);
1229                 if (err)
1230                         return err;
1231         }
1232
1233         /*
1234          * The number of userspace controls are counted control by control,
1235          * not element by element.
1236          */
1237         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1238                 return -ENOMEM;
1239
1240         /* Check the number of elements for this userspace control. */
1241         count = info->owner;
1242         if (count == 0)
1243                 count = 1;
1244
1245         /* Arrange access permissions if needed. */
1246         access = info->access;
1247         if (access == 0)
1248                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1249         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1250                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1251                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE);
1252         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)
1253                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1254         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1255
1256         /*
1257          * Check information and calculate the size of data specific to
1258          * this userspace control.
1259          */
1260         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1261             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1262                 return -EINVAL;
1263         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1264             info->value.enumerated.items == 0)
1265                 return -EINVAL;
1266         if (info->count < 1 ||
1267             info->count > max_value_counts[info->type])
1268                 return -EINVAL;
1269         private_size = value_sizes[info->type] * info->count;
1270
1271         /*
1272          * Keep memory object for this userspace control. After passing this
1273          * code block, the instance should be freed by snd_ctl_free_one().
1274          *
1275          * Note that these elements in this control are locked.
1276          */
1277         err = snd_ctl_new(&kctl, count, access, file);
1278         if (err < 0)
1279                 return err;
1280         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1281         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size,
1282                                      GFP_KERNEL);
1283         if (kctl->private_data == NULL) {
1284                 kfree(kctl);
1285                 return -ENOMEM;
1286         }
1287         kctl->private_free = snd_ctl_elem_user_free;
1288
1289         /* Set private data for this userspace control. */
1290         ue = (struct user_element *)kctl->private_data;
1291         ue->card = card;
1292         ue->info = *info;
1293         ue->info.access = 0;
1294         ue->elem_data = (char *)ue + sizeof(*ue);
1295         ue->elem_data_size = private_size;
1296         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1297                 err = snd_ctl_elem_init_enum_names(ue);
1298                 if (err < 0) {
1299                         snd_ctl_free_one(kctl);
1300                         return err;
1301                 }
1302         }
1303
1304         /* Set callback functions. */
1305         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1306                 kctl->info = snd_ctl_elem_user_enum_info;
1307         else
1308                 kctl->info = snd_ctl_elem_user_info;
1309         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1310                 kctl->get = snd_ctl_elem_user_get;
1311         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1312                 kctl->put = snd_ctl_elem_user_put;
1313         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)
1314                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1315
1316         /* This function manage to free the instance on failure. */
1317         err = snd_ctl_add(card, kctl);
1318         if (err < 0)
1319                 return err;
1320         offset = snd_ctl_get_ioff(kctl, &info->id);
1321         snd_ctl_build_ioff(&info->id, kctl, offset);
1322         /*
1323          * Here we cannot fill any field for the number of elements added by
1324          * this operation because there're no specific fields. The usage of
1325          * 'owner' field for this purpose may cause any bugs to userspace
1326          * applications because the field originally means PID of a process
1327          * which locks the element.
1328          */
1329
1330         down_write(&card->controls_rwsem);
1331         card->user_ctl_count++;
1332         up_write(&card->controls_rwsem);
1333
1334         return 0;
1335 }
1336
1337 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1338                                  struct snd_ctl_elem_info __user *_info, int replace)
1339 {
1340         struct snd_ctl_elem_info info;
1341         int err;
1342
1343         if (copy_from_user(&info, _info, sizeof(info)))
1344                 return -EFAULT;
1345         err = snd_ctl_elem_add(file, &info, replace);
1346         if (err < 0)
1347                 return err;
1348         if (copy_to_user(_info, &info, sizeof(info))) {
1349                 snd_ctl_remove_user_ctl(file, &info.id);
1350                 return -EFAULT;
1351         }
1352
1353         return 0;
1354 }
1355
1356 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1357                                struct snd_ctl_elem_id __user *_id)
1358 {
1359         struct snd_ctl_elem_id id;
1360
1361         if (copy_from_user(&id, _id, sizeof(id)))
1362                 return -EFAULT;
1363         return snd_ctl_remove_user_ctl(file, &id);
1364 }
1365
1366 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1367 {
1368         int subscribe;
1369         if (get_user(subscribe, ptr))
1370                 return -EFAULT;
1371         if (subscribe < 0) {
1372                 subscribe = file->subscribed;
1373                 if (put_user(subscribe, ptr))
1374                         return -EFAULT;
1375                 return 0;
1376         }
1377         if (subscribe) {
1378                 file->subscribed = 1;
1379                 return 0;
1380         } else if (file->subscribed) {
1381                 snd_ctl_empty_read_queue(file);
1382                 file->subscribed = 0;
1383         }
1384         return 0;
1385 }
1386
1387 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1388                              struct snd_ctl_tlv __user *_tlv,
1389                              int op_flag)
1390 {
1391         struct snd_card *card = file->card;
1392         struct snd_ctl_tlv tlv;
1393         struct snd_kcontrol *kctl;
1394         struct snd_kcontrol_volatile *vd;
1395         unsigned int len;
1396         int err = 0;
1397
1398         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1399                 return -EFAULT;
1400         if (tlv.length < sizeof(unsigned int) * 2)
1401                 return -EINVAL;
1402         down_read(&card->controls_rwsem);
1403         kctl = snd_ctl_find_numid(card, tlv.numid);
1404         if (kctl == NULL) {
1405                 err = -ENOENT;
1406                 goto __kctl_end;
1407         }
1408         if (kctl->tlv.p == NULL) {
1409                 err = -ENXIO;
1410                 goto __kctl_end;
1411         }
1412         vd = &kctl->vd[tlv.numid - kctl->id.numid];
1413         if ((op_flag == SNDRV_CTL_TLV_OP_READ &&
1414              (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1415             (op_flag == SNDRV_CTL_TLV_OP_WRITE &&
1416              (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1417             (op_flag == SNDRV_CTL_TLV_OP_CMD &&
1418              (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1419                 err = -ENXIO;
1420                 goto __kctl_end;
1421         }
1422         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1423                 if (vd->owner != NULL && vd->owner != file) {
1424                         err = -EPERM;
1425                         goto __kctl_end;
1426                 }
1427                 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1428                 if (err > 0) {
1429                         struct snd_ctl_elem_id id = kctl->id;
1430                         up_read(&card->controls_rwsem);
1431                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);
1432                         return 0;
1433                 }
1434         } else {
1435                 if (op_flag != SNDRV_CTL_ELEM_ACCESS_TLV_READ) {
1436                         err = -ENXIO;
1437                         goto __kctl_end;
1438                 }
1439                 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1440                 if (tlv.length < len) {
1441                         err = -ENOMEM;
1442                         goto __kctl_end;
1443                 }
1444                 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1445                         err = -EFAULT;
1446         }
1447       __kctl_end:
1448         up_read(&card->controls_rwsem);
1449         return err;
1450 }
1451
1452 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1453 {
1454         struct snd_ctl_file *ctl;
1455         struct snd_card *card;
1456         struct snd_kctl_ioctl *p;
1457         void __user *argp = (void __user *)arg;
1458         int __user *ip = argp;
1459         int err;
1460
1461         ctl = file->private_data;
1462         card = ctl->card;
1463         if (snd_BUG_ON(!card))
1464                 return -ENXIO;
1465         switch (cmd) {
1466         case SNDRV_CTL_IOCTL_PVERSION:
1467                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1468         case SNDRV_CTL_IOCTL_CARD_INFO:
1469                 return snd_ctl_card_info(card, ctl, cmd, argp);
1470         case SNDRV_CTL_IOCTL_ELEM_LIST:
1471                 return snd_ctl_elem_list(card, argp);
1472         case SNDRV_CTL_IOCTL_ELEM_INFO:
1473                 return snd_ctl_elem_info_user(ctl, argp);
1474         case SNDRV_CTL_IOCTL_ELEM_READ:
1475                 return snd_ctl_elem_read_user(card, argp);
1476         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1477                 return snd_ctl_elem_write_user(ctl, argp);
1478         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1479                 return snd_ctl_elem_lock(ctl, argp);
1480         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1481                 return snd_ctl_elem_unlock(ctl, argp);
1482         case SNDRV_CTL_IOCTL_ELEM_ADD:
1483                 return snd_ctl_elem_add_user(ctl, argp, 0);
1484         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1485                 return snd_ctl_elem_add_user(ctl, argp, 1);
1486         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1487                 return snd_ctl_elem_remove(ctl, argp);
1488         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1489                 return snd_ctl_subscribe_events(ctl, ip);
1490         case SNDRV_CTL_IOCTL_TLV_READ:
1491                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1492         case SNDRV_CTL_IOCTL_TLV_WRITE:
1493                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1494         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1495                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1496         case SNDRV_CTL_IOCTL_POWER:
1497                 return -ENOPROTOOPT;
1498         case SNDRV_CTL_IOCTL_POWER_STATE:
1499 #ifdef CONFIG_PM
1500                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1501 #else
1502                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1503 #endif
1504         }
1505         down_read(&snd_ioctl_rwsem);
1506         list_for_each_entry(p, &snd_control_ioctls, list) {
1507                 err = p->fioctl(card, ctl, cmd, arg);
1508                 if (err != -ENOIOCTLCMD) {
1509                         up_read(&snd_ioctl_rwsem);
1510                         return err;
1511                 }
1512         }
1513         up_read(&snd_ioctl_rwsem);
1514         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1515         return -ENOTTY;
1516 }
1517
1518 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1519                             size_t count, loff_t * offset)
1520 {
1521         struct snd_ctl_file *ctl;
1522         int err = 0;
1523         ssize_t result = 0;
1524
1525         ctl = file->private_data;
1526         if (snd_BUG_ON(!ctl || !ctl->card))
1527                 return -ENXIO;
1528         if (!ctl->subscribed)
1529                 return -EBADFD;
1530         if (count < sizeof(struct snd_ctl_event))
1531                 return -EINVAL;
1532         spin_lock_irq(&ctl->read_lock);
1533         while (count >= sizeof(struct snd_ctl_event)) {
1534                 struct snd_ctl_event ev;
1535                 struct snd_kctl_event *kev;
1536                 while (list_empty(&ctl->events)) {
1537                         wait_queue_t wait;
1538                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1539                                 err = -EAGAIN;
1540                                 goto __end_lock;
1541                         }
1542                         init_waitqueue_entry(&wait, current);
1543                         add_wait_queue(&ctl->change_sleep, &wait);
1544                         set_current_state(TASK_INTERRUPTIBLE);
1545                         spin_unlock_irq(&ctl->read_lock);
1546                         schedule();
1547                         remove_wait_queue(&ctl->change_sleep, &wait);
1548                         if (ctl->card->shutdown)
1549                                 return -ENODEV;
1550                         if (signal_pending(current))
1551                                 return -ERESTARTSYS;
1552                         spin_lock_irq(&ctl->read_lock);
1553                 }
1554                 kev = snd_kctl_event(ctl->events.next);
1555                 ev.type = SNDRV_CTL_EVENT_ELEM;
1556                 ev.data.elem.mask = kev->mask;
1557                 ev.data.elem.id = kev->id;
1558                 list_del(&kev->list);
1559                 spin_unlock_irq(&ctl->read_lock);
1560                 kfree(kev);
1561                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1562                         err = -EFAULT;
1563                         goto __end;
1564                 }
1565                 spin_lock_irq(&ctl->read_lock);
1566                 buffer += sizeof(struct snd_ctl_event);
1567                 count -= sizeof(struct snd_ctl_event);
1568                 result += sizeof(struct snd_ctl_event);
1569         }
1570       __end_lock:
1571         spin_unlock_irq(&ctl->read_lock);
1572       __end:
1573         return result > 0 ? result : err;
1574 }
1575
1576 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1577 {
1578         unsigned int mask;
1579         struct snd_ctl_file *ctl;
1580
1581         ctl = file->private_data;
1582         if (!ctl->subscribed)
1583                 return 0;
1584         poll_wait(file, &ctl->change_sleep, wait);
1585
1586         mask = 0;
1587         if (!list_empty(&ctl->events))
1588                 mask |= POLLIN | POLLRDNORM;
1589
1590         return mask;
1591 }
1592
1593 /*
1594  * register the device-specific control-ioctls.
1595  * called from each device manager like pcm.c, hwdep.c, etc.
1596  */
1597 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1598 {
1599         struct snd_kctl_ioctl *pn;
1600
1601         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1602         if (pn == NULL)
1603                 return -ENOMEM;
1604         pn->fioctl = fcn;
1605         down_write(&snd_ioctl_rwsem);
1606         list_add_tail(&pn->list, lists);
1607         up_write(&snd_ioctl_rwsem);
1608         return 0;
1609 }
1610
1611 /**
1612  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1613  * @fcn: ioctl callback function
1614  *
1615  * called from each device manager like pcm.c, hwdep.c, etc.
1616  */
1617 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1618 {
1619         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1620 }
1621 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1622
1623 #ifdef CONFIG_COMPAT
1624 /**
1625  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1626  * control-ioctls
1627  * @fcn: ioctl callback function
1628  */
1629 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1630 {
1631         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1632 }
1633 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1634 #endif
1635
1636 /*
1637  * de-register the device-specific control-ioctls.
1638  */
1639 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1640                                      struct list_head *lists)
1641 {
1642         struct snd_kctl_ioctl *p;
1643
1644         if (snd_BUG_ON(!fcn))
1645                 return -EINVAL;
1646         down_write(&snd_ioctl_rwsem);
1647         list_for_each_entry(p, lists, list) {
1648                 if (p->fioctl == fcn) {
1649                         list_del(&p->list);
1650                         up_write(&snd_ioctl_rwsem);
1651                         kfree(p);
1652                         return 0;
1653                 }
1654         }
1655         up_write(&snd_ioctl_rwsem);
1656         snd_BUG();
1657         return -EINVAL;
1658 }
1659
1660 /**
1661  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1662  * @fcn: ioctl callback function to unregister
1663  */
1664 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1665 {
1666         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1667 }
1668 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1669
1670 #ifdef CONFIG_COMPAT
1671 /**
1672  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1673  * control-ioctls
1674  * @fcn: ioctl callback function to unregister
1675  */
1676 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1677 {
1678         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1679 }
1680 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1681 #endif
1682
1683 static int snd_ctl_fasync(int fd, struct file * file, int on)
1684 {
1685         struct snd_ctl_file *ctl;
1686
1687         ctl = file->private_data;
1688         return fasync_helper(fd, file, on, &ctl->fasync);
1689 }
1690
1691 /* return the preferred subdevice number if already assigned;
1692  * otherwise return -1
1693  */
1694 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1695 {
1696         struct snd_ctl_file *kctl;
1697         int subdevice = -1;
1698
1699         read_lock(&card->ctl_files_rwlock);
1700         list_for_each_entry(kctl, &card->ctl_files, list) {
1701                 if (kctl->pid == task_pid(current)) {
1702                         subdevice = kctl->preferred_subdevice[type];
1703                         if (subdevice != -1)
1704                                 break;
1705                 }
1706         }
1707         read_unlock(&card->ctl_files_rwlock);
1708         return subdevice;
1709 }
1710 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1711
1712 /*
1713  * ioctl32 compat
1714  */
1715 #ifdef CONFIG_COMPAT
1716 #include "control_compat.c"
1717 #else
1718 #define snd_ctl_ioctl_compat    NULL
1719 #endif
1720
1721 /*
1722  *  INIT PART
1723  */
1724
1725 static const struct file_operations snd_ctl_f_ops =
1726 {
1727         .owner =        THIS_MODULE,
1728         .read =         snd_ctl_read,
1729         .open =         snd_ctl_open,
1730         .release =      snd_ctl_release,
1731         .llseek =       no_llseek,
1732         .poll =         snd_ctl_poll,
1733         .unlocked_ioctl =       snd_ctl_ioctl,
1734         .compat_ioctl = snd_ctl_ioctl_compat,
1735         .fasync =       snd_ctl_fasync,
1736 };
1737
1738 /*
1739  * registration of the control device
1740  */
1741 static int snd_ctl_dev_register(struct snd_device *device)
1742 {
1743         struct snd_card *card = device->device_data;
1744
1745         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1746                                    &snd_ctl_f_ops, card, &card->ctl_dev);
1747 }
1748
1749 /*
1750  * disconnection of the control device
1751  */
1752 static int snd_ctl_dev_disconnect(struct snd_device *device)
1753 {
1754         struct snd_card *card = device->device_data;
1755         struct snd_ctl_file *ctl;
1756
1757         read_lock(&card->ctl_files_rwlock);
1758         list_for_each_entry(ctl, &card->ctl_files, list) {
1759                 wake_up(&ctl->change_sleep);
1760                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1761         }
1762         read_unlock(&card->ctl_files_rwlock);
1763
1764         return snd_unregister_device(&card->ctl_dev);
1765 }
1766
1767 /*
1768  * free all controls
1769  */
1770 static int snd_ctl_dev_free(struct snd_device *device)
1771 {
1772         struct snd_card *card = device->device_data;
1773         struct snd_kcontrol *control;
1774
1775         down_write(&card->controls_rwsem);
1776         while (!list_empty(&card->controls)) {
1777                 control = snd_kcontrol(card->controls.next);
1778                 snd_ctl_remove(card, control);
1779         }
1780         up_write(&card->controls_rwsem);
1781         put_device(&card->ctl_dev);
1782         return 0;
1783 }
1784
1785 /*
1786  * create control core:
1787  * called from init.c
1788  */
1789 int snd_ctl_create(struct snd_card *card)
1790 {
1791         static struct snd_device_ops ops = {
1792                 .dev_free = snd_ctl_dev_free,
1793                 .dev_register = snd_ctl_dev_register,
1794                 .dev_disconnect = snd_ctl_dev_disconnect,
1795         };
1796         int err;
1797
1798         if (snd_BUG_ON(!card))
1799                 return -ENXIO;
1800         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1801                 return -ENXIO;
1802
1803         snd_device_initialize(&card->ctl_dev, card);
1804         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1805
1806         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1807         if (err < 0)
1808                 put_device(&card->ctl_dev);
1809         return err;
1810 }
1811
1812 /*
1813  * Frequently used control callbacks/helpers
1814  */
1815
1816 /**
1817  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1818  * callback with a mono channel
1819  * @kcontrol: the kcontrol instance
1820  * @uinfo: info to store
1821  *
1822  * This is a function that can be used as info callback for a standard
1823  * boolean control with a single mono channel.
1824  */
1825 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1826                               struct snd_ctl_elem_info *uinfo)
1827 {
1828         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1829         uinfo->count = 1;
1830         uinfo->value.integer.min = 0;
1831         uinfo->value.integer.max = 1;
1832         return 0;
1833 }
1834 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1835
1836 /**
1837  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1838  * callback with stereo two channels
1839  * @kcontrol: the kcontrol instance
1840  * @uinfo: info to store
1841  *
1842  * This is a function that can be used as info callback for a standard
1843  * boolean control with stereo two channels.
1844  */
1845 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1846                                 struct snd_ctl_elem_info *uinfo)
1847 {
1848         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1849         uinfo->count = 2;
1850         uinfo->value.integer.min = 0;
1851         uinfo->value.integer.max = 1;
1852         return 0;
1853 }
1854 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1855
1856 /**
1857  * snd_ctl_enum_info - fills the info structure for an enumerated control
1858  * @info: the structure to be filled
1859  * @channels: the number of the control's channels; often one
1860  * @items: the number of control values; also the size of @names
1861  * @names: an array containing the names of all control values
1862  *
1863  * Sets all required fields in @info to their appropriate values.
1864  * If the control's accessibility is not the default (readable and writable),
1865  * the caller has to fill @info->access.
1866  *
1867  * Return: Zero.
1868  */
1869 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1870                       unsigned int items, const char *const names[])
1871 {
1872         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1873         info->count = channels;
1874         info->value.enumerated.items = items;
1875         if (!items)
1876                 return 0;
1877         if (info->value.enumerated.item >= items)
1878                 info->value.enumerated.item = items - 1;
1879         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1880              "ALSA: too long item name '%s'\n",
1881              names[info->value.enumerated.item]);
1882         strlcpy(info->value.enumerated.name,
1883                 names[info->value.enumerated.item],
1884                 sizeof(info->value.enumerated.name));
1885         return 0;
1886 }
1887 EXPORT_SYMBOL(snd_ctl_enum_info);