sound/core/control.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  Routines for driver control interface
0004  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
0005  */
0006
0007 #include <linux/threads.h>
0008 #include <linux/interrupt.h>
0009 #include <linux/module.h>
0010 #include <linux/moduleparam.h>
0011 #include <linux/slab.h>
0012 #include <linux/vmalloc.h>
0013 #include <linux/time.h>
0014 #include <linux/mm.h>
0015 #include <linux/math64.h>
0016 #include <linux/sched/signal.h>
0017 #include <sound/core.h>
0018 #include <sound/minors.h>
0019 #include <sound/info.h>
0020 #include <sound/control.h>
0021
0022 // Max allocation size for user controls.
0023 static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
0024 module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
0025 MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
0026
0027 #define MAX_CONTROL_COUNT   1028
0028
0029 struct snd_kctl_ioctl {
0030     struct list_head list;      /* list of all ioctls */
0031     snd_kctl_ioctl_func_t fioctl;
0032 };
0033
0034 static DECLARE_RWSEM(snd_ioctl_rwsem);
0035 static DECLARE_RWSEM(snd_ctl_layer_rwsem);
0036 static LIST_HEAD(snd_control_ioctls);
0037 #ifdef CONFIG_COMPAT
0038 static LIST_HEAD(snd_control_compat_ioctls);
0039 #endif
0040 static struct snd_ctl_layer_ops *snd_ctl_layer;
0041
0042 static int snd_ctl_open(struct inode *inode, struct file *file)
0043 {
0044     unsigned long flags;
0045     struct snd_card *card;
0046     struct snd_ctl_file *ctl;
0047     int i, err;
0048
0049     err = stream_open(inode, file);
0050     if (err < 0)
0051         return err;
0052
0053     card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
0054     if (!card) {
0055         err = -ENODEV;
0056         goto __error1;
0057     }
0058     err = snd_card_file_add(card, file);
0059     if (err < 0) {
0060         err = -ENODEV;
0061         goto __error1;
0062     }
0063     if (!try_module_get(card->module)) {
0064         err = -EFAULT;
0065         goto __error2;
0066     }
0067     ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
0068     if (ctl == NULL) {
0069         err = -ENOMEM;
0070         goto __error;
0071     }
0072     INIT_LIST_HEAD(&ctl->events);
0073     init_waitqueue_head(&ctl->change_sleep);
0074     spin_lock_init(&ctl->read_lock);
0075     ctl->card = card;
0076     for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
0077         ctl->preferred_subdevice[i] = -1;
0078     ctl->pid = get_pid(task_pid(current));
0079     file->private_data = ctl;
0080     write_lock_irqsave(&card->ctl_files_rwlock, flags);
0081     list_add_tail(&ctl->list, &card->ctl_files);
0082     write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
0083     snd_card_unref(card);
0084     return 0;
0085
0086       __error:
0087     module_put(card->module);
0088       __error2:
0089     snd_card_file_remove(card, file);
0090       __error1:
0091     if (card)
0092         snd_card_unref(card);
0093         return err;
0094 }
0095
0096 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
0097 {
0098     unsigned long flags;
0099     struct snd_kctl_event *cread;
0100
0101     spin_lock_irqsave(&ctl->read_lock, flags);
0102     while (!list_empty(&ctl->events)) {
0103         cread = snd_kctl_event(ctl->events.next);
0104         list_del(&cread->list);
0105         kfree(cread);
0106     }
0107     spin_unlock_irqrestore(&ctl->read_lock, flags);
0108 }
0109
0110 static int snd_ctl_release(struct inode *inode, struct file *file)
0111 {
0112     unsigned long flags;
0113     struct snd_card *card;
0114     struct snd_ctl_file *ctl;
0115     struct snd_kcontrol *control;
0116     unsigned int idx;
0117
0118     ctl = file->private_data;
0119     file->private_data = NULL;
0120     card = ctl->card;
0121     write_lock_irqsave(&card->ctl_files_rwlock, flags);
0122     list_del(&ctl->list);
0123     write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
0124     down_write(&card->controls_rwsem);
0125     list_for_each_entry(control, &card->controls, list)
0126         for (idx = 0; idx < control->count; idx++)
0127             if (control->vd[idx].owner == ctl)
0128                 control->vd[idx].owner = NULL;
0129     up_write(&card->controls_rwsem);
0130     snd_fasync_free(ctl->fasync);
0131     snd_ctl_empty_read_queue(ctl);
0132     put_pid(ctl->pid);
0133     kfree(ctl);
0134     module_put(card->module);
0135     snd_card_file_remove(card, file);
0136     return 0;
0137 }
0138
0139 /**
0140  * snd_ctl_notify - Send notification to user-space for a control change
0141  * @card: the card to send notification
0142  * @mask: the event mask, SNDRV_CTL_EVENT_*
0143  * @id: the ctl element id to send notification
0144  *
0145  * This function adds an event record with the given id and mask, appends
0146  * to the list and wakes up the user-space for notification.  This can be
0147  * called in the atomic context.
0148  */
0149 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
0150             struct snd_ctl_elem_id *id)
0151 {
0152     unsigned long flags;
0153     struct snd_ctl_file *ctl;
0154     struct snd_kctl_event *ev;
0155
0156     if (snd_BUG_ON(!card || !id))
0157         return;
0158     if (card->shutdown)
0159         return;
0160     read_lock_irqsave(&card->ctl_files_rwlock, flags);
0161 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
0162     card->mixer_oss_change_count++;
0163 #endif
0164     list_for_each_entry(ctl, &card->ctl_files, list) {
0165         if (!ctl->subscribed)
0166             continue;
0167         spin_lock(&ctl->read_lock);
0168         list_for_each_entry(ev, &ctl->events, list) {
0169             if (ev->id.numid == id->numid) {
0170                 ev->mask |= mask;
0171                 goto _found;
0172             }
0173         }
0174         ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
0175         if (ev) {
0176             ev->id = *id;
0177             ev->mask = mask;
0178             list_add_tail(&ev->list, &ctl->events);
0179         } else {
0180             dev_err(card->dev, "No memory available to allocate event\n");
0181         }
0182     _found:
0183         wake_up(&ctl->change_sleep);
0184         spin_unlock(&ctl->read_lock);
0185         snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
0186     }
0187     read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
0188 }
0189 EXPORT_SYMBOL(snd_ctl_notify);
0190
0191 /**
0192  * snd_ctl_notify_one - Send notification to user-space for a control change
0193  * @card: the card to send notification
0194  * @mask: the event mask, SNDRV_CTL_EVENT_*
0195  * @kctl: the pointer with the control instance
0196  * @ioff: the additional offset to the control index
0197  *
0198  * This function calls snd_ctl_notify() and does additional jobs
0199  * like LED state changes.
0200  */
0201 void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
0202             struct snd_kcontrol *kctl, unsigned int ioff)
0203 {
0204     struct snd_ctl_elem_id id = kctl->id;
0205     struct snd_ctl_layer_ops *lops;
0206
0207     id.index += ioff;
0208     id.numid += ioff;
0209     snd_ctl_notify(card, mask, &id);
0210     down_read(&snd_ctl_layer_rwsem);
0211     for (lops = snd_ctl_layer; lops; lops = lops->next)
0212         lops->lnotify(card, mask, kctl, ioff);
0213     up_read(&snd_ctl_layer_rwsem);
0214 }
0215 EXPORT_SYMBOL(snd_ctl_notify_one);
0216
0217 /**
0218  * snd_ctl_new - create a new control instance with some elements
0219  * @kctl: the pointer to store new control instance
0220  * @count: the number of elements in this control
0221  * @access: the default access flags for elements in this control
0222  * @file: given when locking these elements
0223  *
0224  * Allocates a memory object for a new control instance. The instance has
0225  * elements as many as the given number (@count). Each element has given
0226  * access permissions (@access). Each element is locked when @file is given.
0227  *
0228  * Return: 0 on success, error code on failure
0229  */
0230 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
0231                unsigned int access, struct snd_ctl_file *file)
0232 {
0233     unsigned int idx;
0234
0235     if (count == 0 || count > MAX_CONTROL_COUNT)
0236         return -EINVAL;
0237
0238     *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
0239     if (!*kctl)
0240         return -ENOMEM;
0241
0242     for (idx = 0; idx < count; idx++) {
0243         (*kctl)->vd[idx].access = access;
0244         (*kctl)->vd[idx].owner = file;
0245     }
0246     (*kctl)->count = count;
0247
0248     return 0;
0249 }
0250
0251 /**
0252  * snd_ctl_new1 - create a control instance from the template
0253  * @ncontrol: the initialization record
0254  * @private_data: the private data to set
0255  *
0256  * Allocates a new struct snd_kcontrol instance and initialize from the given
0257  * template.  When the access field of ncontrol is 0, it's assumed as
0258  * READWRITE access. When the count field is 0, it's assumes as one.
0259  *
0260  * Return: The pointer of the newly generated instance, or %NULL on failure.
0261  */
0262 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
0263                   void *private_data)
0264 {
0265     struct snd_kcontrol *kctl;
0266     unsigned int count;
0267     unsigned int access;
0268     int err;
0269
0270     if (snd_BUG_ON(!ncontrol || !ncontrol->info))
0271         return NULL;
0272
0273     count = ncontrol->count;
0274     if (count == 0)
0275         count = 1;
0276
0277     access = ncontrol->access;
0278     if (access == 0)
0279         access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
0280     access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
0281            SNDRV_CTL_ELEM_ACCESS_VOLATILE |
0282            SNDRV_CTL_ELEM_ACCESS_INACTIVE |
0283            SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
0284            SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
0285            SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
0286            SNDRV_CTL_ELEM_ACCESS_LED_MASK |
0287            SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
0288
0289     err = snd_ctl_new(&kctl, count, access, NULL);
0290     if (err < 0)
0291         return NULL;
0292
0293     /* The 'numid' member is decided when calling snd_ctl_add(). */
0294     kctl->id.iface = ncontrol->iface;
0295     kctl->id.device = ncontrol->device;
0296     kctl->id.subdevice = ncontrol->subdevice;
0297     if (ncontrol->name) {
0298         strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
0299         if (strcmp(ncontrol->name, kctl->id.name) != 0)
0300             pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
0301                 ncontrol->name, kctl->id.name);
0302     }
0303     kctl->id.index = ncontrol->index;
0304
0305     kctl->info = ncontrol->info;
0306     kctl->get = ncontrol->get;
0307     kctl->put = ncontrol->put;
0308     kctl->tlv.p = ncontrol->tlv.p;
0309
0310     kctl->private_value = ncontrol->private_value;
0311     kctl->private_data = private_data;
0312
0313     return kctl;
0314 }
0315 EXPORT_SYMBOL(snd_ctl_new1);
0316
0317 /**
0318  * snd_ctl_free_one - release the control instance
0319  * @kcontrol: the control instance
0320  *
0321  * Releases the control instance created via snd_ctl_new()
0322  * or snd_ctl_new1().
0323  * Don't call this after the control was added to the card.
0324  */
0325 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
0326 {
0327     if (kcontrol) {
0328         if (kcontrol->private_free)
0329             kcontrol->private_free(kcontrol);
0330         kfree(kcontrol);
0331     }
0332 }
0333 EXPORT_SYMBOL(snd_ctl_free_one);
0334
0335 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
0336                       unsigned int count)
0337 {
0338     struct snd_kcontrol *kctl;
0339
0340     /* Make sure that the ids assigned to the control do not wrap around */
0341     if (card->last_numid >= UINT_MAX - count)
0342         card->last_numid = 0;
0343
0344     list_for_each_entry(kctl, &card->controls, list) {
0345         if (kctl->id.numid < card->last_numid + 1 + count &&
0346             kctl->id.numid + kctl->count > card->last_numid + 1) {
0347                 card->last_numid = kctl->id.numid + kctl->count - 1;
0348             return true;
0349         }
0350     }
0351     return false;
0352 }
0353
0354 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
0355 {
0356     unsigned int iter = 100000;
0357
0358     while (snd_ctl_remove_numid_conflict(card, count)) {
0359         if (--iter == 0) {
0360             /* this situation is very unlikely */
0361             dev_err(card->dev, "unable to allocate new control numid\n");
0362             return -ENOMEM;
0363         }
0364     }
0365     return 0;
0366 }
0367
0368 /* check whether the given id is contained in the given kctl */
0369 static bool elem_id_matches(const struct snd_kcontrol *kctl,
0370                 const struct snd_ctl_elem_id *id)
0371 {
0372     return kctl->id.iface == id->iface &&
0373         kctl->id.device == id->device &&
0374         kctl->id.subdevice == id->subdevice &&
0375         !strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) &&
0376         kctl->id.index <= id->index &&
0377         kctl->id.index + kctl->count > id->index;
0378 }
0379
0380 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
0381 /* Compute a hash key for the corresponding ctl id
0382  * It's for the name lookup, hence the numid is excluded.
0383  * The hash key is bound in LONG_MAX to be used for Xarray key.
0384  */
0385 #define MULTIPLIER  37
0386 static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id)
0387 {
0388     int i;
0389     unsigned long h;
0390
0391     h = id->iface;
0392     h = MULTIPLIER * h + id->device;
0393     h = MULTIPLIER * h + id->subdevice;
0394     for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++)
0395         h = MULTIPLIER * h + id->name[i];
0396     h = MULTIPLIER * h + id->index;
0397     h &= LONG_MAX;
0398     return h;
0399 }
0400
0401 /* add hash entries to numid and ctl xarray tables */
0402 static void add_hash_entries(struct snd_card *card,
0403                  struct snd_kcontrol *kcontrol)
0404 {
0405     struct snd_ctl_elem_id id = kcontrol->id;
0406     int i;
0407
0408     xa_store_range(&card->ctl_numids, kcontrol->id.numid,
0409                kcontrol->id.numid + kcontrol->count - 1,
0410                kcontrol, GFP_KERNEL);
0411
0412     for (i = 0; i < kcontrol->count; i++) {
0413         id.index = kcontrol->id.index + i;
0414         if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id),
0415                   kcontrol, GFP_KERNEL)) {
0416             /* skip hash for this entry, noting we had collision */
0417             card->ctl_hash_collision = true;
0418             dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n",
0419                 id.iface, id.name, id.index);
0420         }
0421     }
0422 }
0423
0424 /* remove hash entries that have been added */
0425 static void remove_hash_entries(struct snd_card *card,
0426                 struct snd_kcontrol *kcontrol)
0427 {
0428     struct snd_ctl_elem_id id = kcontrol->id;
0429     struct snd_kcontrol *matched;
0430     unsigned long h;
0431     int i;
0432
0433     for (i = 0; i < kcontrol->count; i++) {
0434         xa_erase(&card->ctl_numids, id.numid);
0435         h = get_ctl_id_hash(&id);
0436         matched = xa_load(&card->ctl_hash, h);
0437         if (matched && (matched == kcontrol ||
0438                 elem_id_matches(matched, &id)))
0439             xa_erase(&card->ctl_hash, h);
0440         id.index++;
0441         id.numid++;
0442     }
0443 }
0444 #else /* CONFIG_SND_CTL_FAST_LOOKUP */
0445 static inline void add_hash_entries(struct snd_card *card,
0446                     struct snd_kcontrol *kcontrol)
0447 {
0448 }
0449 static inline void remove_hash_entries(struct snd_card *card,
0450                        struct snd_kcontrol *kcontrol)
0451 {
0452 }
0453 #endif /* CONFIG_SND_CTL_FAST_LOOKUP */
0454
0455 enum snd_ctl_add_mode {
0456     CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
0457 };
0458
0459 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
0460 static int __snd_ctl_add_replace(struct snd_card *card,
0461                  struct snd_kcontrol *kcontrol,
0462                  enum snd_ctl_add_mode mode)
0463 {
0464     struct snd_ctl_elem_id id;
0465     unsigned int idx;
0466     struct snd_kcontrol *old;
0467     int err;
0468
0469     id = kcontrol->id;
0470     if (id.index > UINT_MAX - kcontrol->count)
0471         return -EINVAL;
0472
0473     old = snd_ctl_find_id(card, &id);
0474     if (!old) {
0475         if (mode == CTL_REPLACE)
0476             return -EINVAL;
0477     } else {
0478         if (mode == CTL_ADD_EXCLUSIVE) {
0479             dev_err(card->dev,
0480                 "control %i:%i:%i:%s:%i is already present\n",
0481                 id.iface, id.device, id.subdevice, id.name,
0482                 id.index);
0483             return -EBUSY;
0484         }
0485
0486         err = snd_ctl_remove(card, old);
0487         if (err < 0)
0488             return err;
0489     }
0490
0491     if (snd_ctl_find_hole(card, kcontrol->count) < 0)
0492         return -ENOMEM;
0493
0494     list_add_tail(&kcontrol->list, &card->controls);
0495     card->controls_count += kcontrol->count;
0496     kcontrol->id.numid = card->last_numid + 1;
0497     card->last_numid += kcontrol->count;
0498
0499     add_hash_entries(card, kcontrol);
0500
0501     for (idx = 0; idx < kcontrol->count; idx++)
0502         snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
0503
0504     return 0;
0505 }
0506
0507 static int snd_ctl_add_replace(struct snd_card *card,
0508                    struct snd_kcontrol *kcontrol,
0509                    enum snd_ctl_add_mode mode)
0510 {
0511     int err = -EINVAL;
0512
0513     if (! kcontrol)
0514         return err;
0515     if (snd_BUG_ON(!card || !kcontrol->info))
0516         goto error;
0517
0518     down_write(&card->controls_rwsem);
0519     err = __snd_ctl_add_replace(card, kcontrol, mode);
0520     up_write(&card->controls_rwsem);
0521     if (err < 0)
0522         goto error;
0523     return 0;
0524
0525  error:
0526     snd_ctl_free_one(kcontrol);
0527     return err;
0528 }
0529
0530 /**
0531  * snd_ctl_add - add the control instance to the card
0532  * @card: the card instance
0533  * @kcontrol: the control instance to add
0534  *
0535  * Adds the control instance created via snd_ctl_new() or
0536  * snd_ctl_new1() to the given card. Assigns also an unique
0537  * numid used for fast search.
0538  *
0539  * It frees automatically the control which cannot be added.
0540  *
0541  * Return: Zero if successful, or a negative error code on failure.
0542  *
0543  */
0544 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
0545 {
0546     return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
0547 }
0548 EXPORT_SYMBOL(snd_ctl_add);
0549
0550 /**
0551  * snd_ctl_replace - replace the control instance of the card
0552  * @card: the card instance
0553  * @kcontrol: the control instance to replace
0554  * @add_on_replace: add the control if not already added
0555  *
0556  * Replaces the given control.  If the given control does not exist
0557  * and the add_on_replace flag is set, the control is added.  If the
0558  * control exists, it is destroyed first.
0559  *
0560  * It frees automatically the control which cannot be added or replaced.
0561  *
0562  * Return: Zero if successful, or a negative error code on failure.
0563  */
0564 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
0565             bool add_on_replace)
0566 {
0567     return snd_ctl_add_replace(card, kcontrol,
0568                    add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
0569 }
0570 EXPORT_SYMBOL(snd_ctl_replace);
0571
0572 static int __snd_ctl_remove(struct snd_card *card,
0573                 struct snd_kcontrol *kcontrol,
0574                 bool remove_hash)
0575 {
0576     unsigned int idx;
0577
0578     if (snd_BUG_ON(!card || !kcontrol))
0579         return -EINVAL;
0580     list_del(&kcontrol->list);
0581
0582     if (remove_hash)
0583         remove_hash_entries(card, kcontrol);
0584
0585     card->controls_count -= kcontrol->count;
0586     for (idx = 0; idx < kcontrol->count; idx++)
0587         snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
0588     snd_ctl_free_one(kcontrol);
0589     return 0;
0590 }
0591
0592 /**
0593  * snd_ctl_remove - remove the control from the card and release it
0594  * @card: the card instance
0595  * @kcontrol: the control instance to remove
0596  *
0597  * Removes the control from the card and then releases the instance.
0598  * You don't need to call snd_ctl_free_one(). You must be in
0599  * the write lock - down_write(&card->controls_rwsem).
0600  *
0601  * Return: 0 if successful, or a negative error code on failure.
0602  */
0603 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
0604 {
0605     return __snd_ctl_remove(card, kcontrol, true);
0606 }
0607 EXPORT_SYMBOL(snd_ctl_remove);
0608
0609 /**
0610  * snd_ctl_remove_id - remove the control of the given id and release it
0611  * @card: the card instance
0612  * @id: the control id to remove
0613  *
0614  * Finds the control instance with the given id, removes it from the
0615  * card list and releases it.
0616  *
0617  * Return: 0 if successful, or a negative error code on failure.
0618  */
0619 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
0620 {
0621     struct snd_kcontrol *kctl;
0622     int ret;
0623
0624     down_write(&card->controls_rwsem);
0625     kctl = snd_ctl_find_id(card, id);
0626     if (kctl == NULL) {
0627         up_write(&card->controls_rwsem);
0628         return -ENOENT;
0629     }
0630     ret = snd_ctl_remove(card, kctl);
0631     up_write(&card->controls_rwsem);
0632     return ret;
0633 }
0634 EXPORT_SYMBOL(snd_ctl_remove_id);
0635
0636 /**
0637  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
0638  * @file: active control handle
0639  * @id: the control id to remove
0640  *
0641  * Finds the control instance with the given id, removes it from the
0642  * card list and releases it.
0643  *
0644  * Return: 0 if successful, or a negative error code on failure.
0645  */
0646 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
0647                    struct snd_ctl_elem_id *id)
0648 {
0649     struct snd_card *card = file->card;
0650     struct snd_kcontrol *kctl;
0651     int idx, ret;
0652
0653     down_write(&card->controls_rwsem);
0654     kctl = snd_ctl_find_id(card, id);
0655     if (kctl == NULL) {
0656         ret = -ENOENT;
0657         goto error;
0658     }
0659     if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
0660         ret = -EINVAL;
0661         goto error;
0662     }
0663     for (idx = 0; idx < kctl->count; idx++)
0664         if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
0665             ret = -EBUSY;
0666             goto error;
0667         }
0668     ret = snd_ctl_remove(card, kctl);
0669 error:
0670     up_write(&card->controls_rwsem);
0671     return ret;
0672 }
0673
0674 /**
0675  * snd_ctl_activate_id - activate/inactivate the control of the given id
0676  * @card: the card instance
0677  * @id: the control id to activate/inactivate
0678  * @active: non-zero to activate
0679  *
0680  * Finds the control instance with the given id, and activate or
0681  * inactivate the control together with notification, if changed.
0682  * The given ID data is filled with full information.
0683  *
0684  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
0685  */
0686 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
0687             int active)
0688 {
0689     struct snd_kcontrol *kctl;
0690     struct snd_kcontrol_volatile *vd;
0691     unsigned int index_offset;
0692     int ret;
0693
0694     down_write(&card->controls_rwsem);
0695     kctl = snd_ctl_find_id(card, id);
0696     if (kctl == NULL) {
0697         ret = -ENOENT;
0698         goto unlock;
0699     }
0700     index_offset = snd_ctl_get_ioff(kctl, id);
0701     vd = &kctl->vd[index_offset];
0702     ret = 0;
0703     if (active) {
0704         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
0705             goto unlock;
0706         vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
0707     } else {
0708         if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
0709             goto unlock;
0710         vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
0711     }
0712     snd_ctl_build_ioff(id, kctl, index_offset);
0713     downgrade_write(&card->controls_rwsem);
0714     snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
0715     up_read(&card->controls_rwsem);
0716     return 1;
0717
0718  unlock:
0719     up_write(&card->controls_rwsem);
0720     return ret;
0721 }
0722 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
0723
0724 /**
0725  * snd_ctl_rename_id - replace the id of a control on the card
0726  * @card: the card instance
0727  * @src_id: the old id
0728  * @dst_id: the new id
0729  *
0730  * Finds the control with the old id from the card, and replaces the
0731  * id with the new one.
0732  *
0733  * Return: Zero if successful, or a negative error code on failure.
0734  */
0735 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
0736               struct snd_ctl_elem_id *dst_id)
0737 {
0738     struct snd_kcontrol *kctl;
0739
0740     down_write(&card->controls_rwsem);
0741     kctl = snd_ctl_find_id(card, src_id);
0742     if (kctl == NULL) {
0743         up_write(&card->controls_rwsem);
0744         return -ENOENT;
0745     }
0746     remove_hash_entries(card, kctl);
0747     kctl->id = *dst_id;
0748     kctl->id.numid = card->last_numid + 1;
0749     card->last_numid += kctl->count;
0750     add_hash_entries(card, kctl);
0751     up_write(&card->controls_rwsem);
0752     return 0;
0753 }
0754 EXPORT_SYMBOL(snd_ctl_rename_id);
0755
0756 #ifndef CONFIG_SND_CTL_FAST_LOOKUP
0757 static struct snd_kcontrol *
0758 snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
0759 {
0760     struct snd_kcontrol *kctl;
0761
0762     list_for_each_entry(kctl, &card->controls, list) {
0763         if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
0764             return kctl;
0765     }
0766     return NULL;
0767 }
0768 #endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
0769
0770 /**
0771  * snd_ctl_find_numid - find the control instance with the given number-id
0772  * @card: the card instance
0773  * @numid: the number-id to search
0774  *
0775  * Finds the control instance with the given number-id from the card.
0776  *
0777  * The caller must down card->controls_rwsem before calling this function
0778  * (if the race condition can happen).
0779  *
0780  * Return: The pointer of the instance if found, or %NULL if not.
0781  *
0782  */
0783 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
0784 {
0785     if (snd_BUG_ON(!card || !numid))
0786         return NULL;
0787 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
0788     return xa_load(&card->ctl_numids, numid);
0789 #else
0790     return snd_ctl_find_numid_slow(card, numid);
0791 #endif
0792 }
0793 EXPORT_SYMBOL(snd_ctl_find_numid);
0794
0795 /**
0796  * snd_ctl_find_id - find the control instance with the given id
0797  * @card: the card instance
0798  * @id: the id to search
0799  *
0800  * Finds the control instance with the given id from the card.
0801  *
0802  * The caller must down card->controls_rwsem before calling this function
0803  * (if the race condition can happen).
0804  *
0805  * Return: The pointer of the instance if found, or %NULL if not.
0806  *
0807  */
0808 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
0809                      struct snd_ctl_elem_id *id)
0810 {
0811     struct snd_kcontrol *kctl;
0812
0813     if (snd_BUG_ON(!card || !id))
0814         return NULL;
0815     if (id->numid != 0)
0816         return snd_ctl_find_numid(card, id->numid);
0817 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
0818     kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
0819     if (kctl && elem_id_matches(kctl, id))
0820         return kctl;
0821     if (!card->ctl_hash_collision)
0822         return NULL; /* we can rely on only hash table */
0823 #endif
0824     /* no matching in hash table - try all as the last resort */
0825     list_for_each_entry(kctl, &card->controls, list)
0826         if (elem_id_matches(kctl, id))
0827             return kctl;
0828
0829     return NULL;
0830 }
0831 EXPORT_SYMBOL(snd_ctl_find_id);
0832
0833 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
0834                  unsigned int cmd, void __user *arg)
0835 {
0836     struct snd_ctl_card_info *info;
0837
0838     info = kzalloc(sizeof(*info), GFP_KERNEL);
0839     if (! info)
0840         return -ENOMEM;
0841     down_read(&snd_ioctl_rwsem);
0842     info->card = card->number;
0843     strscpy(info->id, card->id, sizeof(info->id));
0844     strscpy(info->driver, card->driver, sizeof(info->driver));
0845     strscpy(info->name, card->shortname, sizeof(info->name));
0846     strscpy(info->longname, card->longname, sizeof(info->longname));
0847     strscpy(info->mixername, card->mixername, sizeof(info->mixername));
0848     strscpy(info->components, card->components, sizeof(info->components));
0849     up_read(&snd_ioctl_rwsem);
0850     if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
0851         kfree(info);
0852         return -EFAULT;
0853     }
0854     kfree(info);
0855     return 0;
0856 }
0857
0858 static int snd_ctl_elem_list(struct snd_card *card,
0859                  struct snd_ctl_elem_list *list)
0860 {
0861     struct snd_kcontrol *kctl;
0862     struct snd_ctl_elem_id id;
0863     unsigned int offset, space, jidx;
0864     int err = 0;
0865
0866     offset = list->offset;
0867     space = list->space;
0868
0869     down_read(&card->controls_rwsem);
0870     list->count = card->controls_count;
0871     list->used = 0;
0872     if (space > 0) {
0873         list_for_each_entry(kctl, &card->controls, list) {
0874             if (offset >= kctl->count) {
0875                 offset -= kctl->count;
0876                 continue;
0877             }
0878             for (jidx = offset; jidx < kctl->count; jidx++) {
0879                 snd_ctl_build_ioff(&id, kctl, jidx);
0880                 if (copy_to_user(list->pids + list->used, &id,
0881                          sizeof(id))) {
0882                     err = -EFAULT;
0883                     goto out;
0884                 }
0885                 list->used++;
0886                 if (!--space)
0887                     goto out;
0888             }
0889             offset = 0;
0890         }
0891     }
0892  out:
0893     up_read(&card->controls_rwsem);
0894     return err;
0895 }
0896
0897 static int snd_ctl_elem_list_user(struct snd_card *card,
0898                   struct snd_ctl_elem_list __user *_list)
0899 {
0900     struct snd_ctl_elem_list list;
0901     int err;
0902
0903     if (copy_from_user(&list, _list, sizeof(list)))
0904         return -EFAULT;
0905     err = snd_ctl_elem_list(card, &list);
0906     if (err)
0907         return err;
0908     if (copy_to_user(_list, &list, sizeof(list)))
0909         return -EFAULT;
0910
0911     return 0;
0912 }
0913
0914 /* Check whether the given kctl info is valid */
0915 static int snd_ctl_check_elem_info(struct snd_card *card,
0916                    const struct snd_ctl_elem_info *info)
0917 {
0918     static const unsigned int max_value_counts[] = {
0919         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
0920         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
0921         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
0922         [SNDRV_CTL_ELEM_TYPE_BYTES] = 512,
0923         [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
0924         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
0925     };
0926
0927     if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
0928         info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
0929         if (card)
0930             dev_err(card->dev,
0931                 "control %i:%i:%i:%s:%i: invalid type %d\n",
0932                 info->id.iface, info->id.device,
0933                 info->id.subdevice, info->id.name,
0934                 info->id.index, info->type);
0935         return -EINVAL;
0936     }
0937     if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
0938         info->value.enumerated.items == 0) {
0939         if (card)
0940             dev_err(card->dev,
0941                 "control %i:%i:%i:%s:%i: zero enum items\n",
0942                 info->id.iface, info->id.device,
0943                 info->id.subdevice, info->id.name,
0944                 info->id.index);
0945         return -EINVAL;
0946     }
0947     if (info->count > max_value_counts[info->type]) {
0948         if (card)
0949             dev_err(card->dev,
0950                 "control %i:%i:%i:%s:%i: invalid count %d\n",
0951                 info->id.iface, info->id.device,
0952                 info->id.subdevice, info->id.name,
0953                 info->id.index, info->count);
0954         return -EINVAL;
0955     }
0956
0957     return 0;
0958 }
0959
0960 /* The capacity of struct snd_ctl_elem_value.value.*/
0961 static const unsigned int value_sizes[] = {
0962     [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
0963     [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
0964     [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
0965     [SNDRV_CTL_ELEM_TYPE_BYTES] = sizeof(unsigned char),
0966     [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
0967     [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
0968 };
0969
0970 /* fill the remaining snd_ctl_elem_value data with the given pattern */
0971 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
0972                       struct snd_ctl_elem_info *info,
0973                       u32 pattern)
0974 {
0975     size_t offset = value_sizes[info->type] * info->count;
0976
0977     offset = DIV_ROUND_UP(offset, sizeof(u32));
0978     memset32((u32 *)control->value.bytes.data + offset, pattern,
0979          sizeof(control->value) / sizeof(u32) - offset);
0980 }
0981
0982 /* check whether the given integer ctl value is valid */
0983 static int sanity_check_int_value(struct snd_card *card,
0984                   const struct snd_ctl_elem_value *control,
0985                   const struct snd_ctl_elem_info *info,
0986                   int i, bool print_error)
0987 {
0988     long long lval, lmin, lmax, lstep;
0989     u64 rem;
0990
0991     switch (info->type) {
0992     default:
0993     case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
0994         lval = control->value.integer.value[i];
0995         lmin = 0;
0996         lmax = 1;
0997         lstep = 0;
0998         break;
0999     case SNDRV_CTL_ELEM_TYPE_INTEGER:
1000         lval = control->value.integer.value[i];
1001         lmin = info->value.integer.min;
1002         lmax = info->value.integer.max;
1003         lstep = info->value.integer.step;
1004         break;
1005     case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1006         lval = control->value.integer64.value[i];
1007         lmin = info->value.integer64.min;
1008         lmax = info->value.integer64.max;
1009         lstep = info->value.integer64.step;
1010         break;
1011     case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1012         lval = control->value.enumerated.item[i];
1013         lmin = 0;
1014         lmax = info->value.enumerated.items - 1;
1015         lstep = 0;
1016         break;
1017     }
1018
1019     if (lval < lmin || lval > lmax) {
1020         if (print_error)
1021             dev_err(card->dev,
1022                 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
1023                 control->id.iface, control->id.device,
1024                 control->id.subdevice, control->id.name,
1025                 control->id.index, lval, lmin, lmax, i);
1026         return -EINVAL;
1027     }
1028     if (lstep) {
1029         div64_u64_rem(lval, lstep, &rem);
1030         if (rem) {
1031             if (print_error)
1032                 dev_err(card->dev,
1033                     "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
1034                     control->id.iface, control->id.device,
1035                     control->id.subdevice, control->id.name,
1036                     control->id.index, lval, lstep, i);
1037             return -EINVAL;
1038         }
1039     }
1040
1041     return 0;
1042 }
1043
1044 /* check whether the all input values are valid for the given elem value */
1045 static int sanity_check_input_values(struct snd_card *card,
1046                      const struct snd_ctl_elem_value *control,
1047                      const struct snd_ctl_elem_info *info,
1048                      bool print_error)
1049 {
1050     int i, ret;
1051
1052     switch (info->type) {
1053     case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1054     case SNDRV_CTL_ELEM_TYPE_INTEGER:
1055     case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1056     case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1057         for (i = 0; i < info->count; i++) {
1058             ret = sanity_check_int_value(card, control, info, i,
1059                              print_error);
1060             if (ret < 0)
1061                 return ret;
1062         }
1063         break;
1064     default:
1065         break;
1066     }
1067
1068     return 0;
1069 }
1070
1071 /* perform sanity checks to the given snd_ctl_elem_value object */
1072 static int sanity_check_elem_value(struct snd_card *card,
1073                    const struct snd_ctl_elem_value *control,
1074                    const struct snd_ctl_elem_info *info,
1075                    u32 pattern)
1076 {
1077     size_t offset;
1078     int ret;
1079     u32 *p;
1080
1081     ret = sanity_check_input_values(card, control, info, true);
1082     if (ret < 0)
1083         return ret;
1084
1085     /* check whether the remaining area kept untouched */
1086     offset = value_sizes[info->type] * info->count;
1087     offset = DIV_ROUND_UP(offset, sizeof(u32));
1088     p = (u32 *)control->value.bytes.data + offset;
1089     for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
1090         if (*p != pattern) {
1091             ret = -EINVAL;
1092             break;
1093         }
1094         *p = 0; /* clear the checked area */
1095     }
1096
1097     return ret;
1098 }
1099
1100 static int __snd_ctl_elem_info(struct snd_card *card,
1101                    struct snd_kcontrol *kctl,
1102                    struct snd_ctl_elem_info *info,
1103                    struct snd_ctl_file *ctl)
1104 {
1105     struct snd_kcontrol_volatile *vd;
1106     unsigned int index_offset;
1107     int result;
1108
1109 #ifdef CONFIG_SND_DEBUG
1110     info->access = 0;
1111 #endif
1112     result = snd_power_ref_and_wait(card);
1113     if (!result)
1114         result = kctl->info(kctl, info);
1115     snd_power_unref(card);
1116     if (result >= 0) {
1117         snd_BUG_ON(info->access);
1118         index_offset = snd_ctl_get_ioff(kctl, &info->id);
1119         vd = &kctl->vd[index_offset];
1120         snd_ctl_build_ioff(&info->id, kctl, index_offset);
1121         info->access = vd->access;
1122         if (vd->owner) {
1123             info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
1124             if (vd->owner == ctl)
1125                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
1126             info->owner = pid_vnr(vd->owner->pid);
1127         } else {
1128             info->owner = -1;
1129         }
1130         if (!snd_ctl_skip_validation(info) &&
1131             snd_ctl_check_elem_info(card, info) < 0)
1132             result = -EINVAL;
1133     }
1134     return result;
1135 }
1136
1137 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
1138                  struct snd_ctl_elem_info *info)
1139 {
1140     struct snd_card *card = ctl->card;
1141     struct snd_kcontrol *kctl;
1142     int result;
1143
1144     down_read(&card->controls_rwsem);
1145     kctl = snd_ctl_find_id(card, &info->id);
1146     if (kctl == NULL)
1147         result = -ENOENT;
1148     else
1149         result = __snd_ctl_elem_info(card, kctl, info, ctl);
1150     up_read(&card->controls_rwsem);
1151     return result;
1152 }
1153
1154 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1155                   struct snd_ctl_elem_info __user *_info)
1156 {
1157     struct snd_ctl_elem_info info;
1158     int result;
1159
1160     if (copy_from_user(&info, _info, sizeof(info)))
1161         return -EFAULT;
1162     result = snd_ctl_elem_info(ctl, &info);
1163     if (result < 0)
1164         return result;
1165     /* drop internal access flags */
1166     info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
1167              SNDRV_CTL_ELEM_ACCESS_LED_MASK);
1168     if (copy_to_user(_info, &info, sizeof(info)))
1169         return -EFAULT;
1170     return result;
1171 }
1172
1173 static int snd_ctl_elem_read(struct snd_card *card,
1174                  struct snd_ctl_elem_value *control)
1175 {
1176     struct snd_kcontrol *kctl;
1177     struct snd_kcontrol_volatile *vd;
1178     unsigned int index_offset;
1179     struct snd_ctl_elem_info info;
1180     const u32 pattern = 0xdeadbeef;
1181     int ret;
1182
1183     kctl = snd_ctl_find_id(card, &control->id);
1184     if (kctl == NULL)
1185         return -ENOENT;
1186
1187     index_offset = snd_ctl_get_ioff(kctl, &control->id);
1188     vd = &kctl->vd[index_offset];
1189     if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1190         return -EPERM;
1191
1192     snd_ctl_build_ioff(&control->id, kctl, index_offset);
1193
1194 #ifdef CONFIG_SND_CTL_DEBUG
1195     /* info is needed only for validation */
1196     memset(&info, 0, sizeof(info));
1197     info.id = control->id;
1198     ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1199     if (ret < 0)
1200         return ret;
1201 #endif
1202
1203     if (!snd_ctl_skip_validation(&info))
1204         fill_remaining_elem_value(control, &info, pattern);
1205     ret = snd_power_ref_and_wait(card);
1206     if (!ret)
1207         ret = kctl->get(kctl, control);
1208     snd_power_unref(card);
1209     if (ret < 0)
1210         return ret;
1211     if (!snd_ctl_skip_validation(&info) &&
1212         sanity_check_elem_value(card, control, &info, pattern) < 0) {
1213         dev_err(card->dev,
1214             "control %i:%i:%i:%s:%i: access overflow\n",
1215             control->id.iface, control->id.device,
1216             control->id.subdevice, control->id.name,
1217             control->id.index);
1218         return -EINVAL;
1219     }
1220     return ret;
1221 }
1222
1223 static int snd_ctl_elem_read_user(struct snd_card *card,
1224                   struct snd_ctl_elem_value __user *_control)
1225 {
1226     struct snd_ctl_elem_value *control;
1227     int result;
1228
1229     control = memdup_user(_control, sizeof(*control));
1230     if (IS_ERR(control))
1231         return PTR_ERR(control);
1232
1233     down_read(&card->controls_rwsem);
1234     result = snd_ctl_elem_read(card, control);
1235     up_read(&card->controls_rwsem);
1236     if (result < 0)
1237         goto error;
1238
1239     if (copy_to_user(_control, control, sizeof(*control)))
1240         result = -EFAULT;
1241  error:
1242     kfree(control);
1243     return result;
1244 }
1245
1246 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1247                   struct snd_ctl_elem_value *control)
1248 {
1249     struct snd_kcontrol *kctl;
1250     struct snd_kcontrol_volatile *vd;
1251     unsigned int index_offset;
1252     int result;
1253
1254     down_write(&card->controls_rwsem);
1255     kctl = snd_ctl_find_id(card, &control->id);
1256     if (kctl == NULL) {
1257         up_write(&card->controls_rwsem);
1258         return -ENOENT;
1259     }
1260
1261     index_offset = snd_ctl_get_ioff(kctl, &control->id);
1262     vd = &kctl->vd[index_offset];
1263     if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1264         (file && vd->owner && vd->owner != file)) {
1265         up_write(&card->controls_rwsem);
1266         return -EPERM;
1267     }
1268
1269     snd_ctl_build_ioff(&control->id, kctl, index_offset);
1270     result = snd_power_ref_and_wait(card);
1271     /* validate input values */
1272     if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION) && !result) {
1273         struct snd_ctl_elem_info info;
1274
1275         memset(&info, 0, sizeof(info));
1276         info.id = control->id;
1277         result = __snd_ctl_elem_info(card, kctl, &info, NULL);
1278         if (!result)
1279             result = sanity_check_input_values(card, control, &info,
1280                                false);
1281     }
1282     if (!result)
1283         result = kctl->put(kctl, control);
1284     snd_power_unref(card);
1285     if (result < 0) {
1286         up_write(&card->controls_rwsem);
1287         return result;
1288     }
1289
1290     if (result > 0) {
1291         downgrade_write(&card->controls_rwsem);
1292         snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
1293         up_read(&card->controls_rwsem);
1294     } else {
1295         up_write(&card->controls_rwsem);
1296     }
1297
1298     return 0;
1299 }
1300
1301 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1302                    struct snd_ctl_elem_value __user *_control)
1303 {
1304     struct snd_ctl_elem_value *control;
1305     struct snd_card *card;
1306     int result;
1307
1308     control = memdup_user(_control, sizeof(*control));
1309     if (IS_ERR(control))
1310         return PTR_ERR(control);
1311
1312     card = file->card;
1313     result = snd_ctl_elem_write(card, file, control);
1314     if (result < 0)
1315         goto error;
1316
1317     if (copy_to_user(_control, control, sizeof(*control)))
1318         result = -EFAULT;
1319  error:
1320     kfree(control);
1321     return result;
1322 }
1323
1324 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1325                  struct snd_ctl_elem_id __user *_id)
1326 {
1327     struct snd_card *card = file->card;
1328     struct snd_ctl_elem_id id;
1329     struct snd_kcontrol *kctl;
1330     struct snd_kcontrol_volatile *vd;
1331     int result;
1332
1333     if (copy_from_user(&id, _id, sizeof(id)))
1334         return -EFAULT;
1335     down_write(&card->controls_rwsem);
1336     kctl = snd_ctl_find_id(card, &id);
1337     if (kctl == NULL) {
1338         result = -ENOENT;
1339     } else {
1340         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1341         if (vd->owner != NULL)
1342             result = -EBUSY;
1343         else {
1344             vd->owner = file;
1345             result = 0;
1346         }
1347     }
1348     up_write(&card->controls_rwsem);
1349     return result;
1350 }
1351
1352 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1353                    struct snd_ctl_elem_id __user *_id)
1354 {
1355     struct snd_card *card = file->card;
1356     struct snd_ctl_elem_id id;
1357     struct snd_kcontrol *kctl;
1358     struct snd_kcontrol_volatile *vd;
1359     int result;
1360
1361     if (copy_from_user(&id, _id, sizeof(id)))
1362         return -EFAULT;
1363     down_write(&card->controls_rwsem);
1364     kctl = snd_ctl_find_id(card, &id);
1365     if (kctl == NULL) {
1366         result = -ENOENT;
1367     } else {
1368         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1369         if (vd->owner == NULL)
1370             result = -EINVAL;
1371         else if (vd->owner != file)
1372             result = -EPERM;
1373         else {
1374             vd->owner = NULL;
1375             result = 0;
1376         }
1377     }
1378     up_write(&card->controls_rwsem);
1379     return result;
1380 }
1381
1382 struct user_element {
1383     struct snd_ctl_elem_info info;
1384     struct snd_card *card;
1385     char *elem_data;        /* element data */
1386     unsigned long elem_data_size;   /* size of element data in bytes */
1387     void *tlv_data;         /* TLV data */
1388     unsigned long tlv_data_size;    /* TLV data size */
1389     void *priv_data;        /* private data (like strings for enumerated type) */
1390 };
1391
1392 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1393 static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
1394 {
1395     return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
1396 }
1397
1398 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1399                   struct snd_ctl_elem_info *uinfo)
1400 {
1401     struct user_element *ue = kcontrol->private_data;
1402     unsigned int offset;
1403
1404     offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1405     *uinfo = ue->info;
1406     snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1407
1408     return 0;
1409 }
1410
1411 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1412                        struct snd_ctl_elem_info *uinfo)
1413 {
1414     struct user_element *ue = kcontrol->private_data;
1415     const char *names;
1416     unsigned int item;
1417     unsigned int offset;
1418
1419     item = uinfo->value.enumerated.item;
1420
1421     offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1422     *uinfo = ue->info;
1423     snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1424
1425     item = min(item, uinfo->value.enumerated.items - 1);
1426     uinfo->value.enumerated.item = item;
1427
1428     names = ue->priv_data;
1429     for (; item > 0; --item)
1430         names += strlen(names) + 1;
1431     strcpy(uinfo->value.enumerated.name, names);
1432
1433     return 0;
1434 }
1435
1436 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1437                  struct snd_ctl_elem_value *ucontrol)
1438 {
1439     struct user_element *ue = kcontrol->private_data;
1440     unsigned int size = ue->elem_data_size;
1441     char *src = ue->elem_data +
1442             snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1443
1444     memcpy(&ucontrol->value, src, size);
1445     return 0;
1446 }
1447
1448 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1449                  struct snd_ctl_elem_value *ucontrol)
1450 {
1451     int change;
1452     struct user_element *ue = kcontrol->private_data;
1453     unsigned int size = ue->elem_data_size;
1454     char *dst = ue->elem_data +
1455             snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1456
1457     change = memcmp(&ucontrol->value, dst, size) != 0;
1458     if (change)
1459         memcpy(dst, &ucontrol->value, size);
1460     return change;
1461 }
1462
1463 /* called in controls_rwsem write lock */
1464 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1465                 unsigned int size)
1466 {
1467     struct user_element *ue = kctl->private_data;
1468     unsigned int *container;
1469     unsigned int mask = 0;
1470     int i;
1471     int change;
1472
1473     if (size > 1024 * 128)  /* sane value */
1474         return -EINVAL;
1475
1476     // does the TLV size change cause overflow?
1477     if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
1478         return -ENOMEM;
1479
1480     container = vmemdup_user(buf, size);
1481     if (IS_ERR(container))
1482         return PTR_ERR(container);
1483
1484     change = ue->tlv_data_size != size;
1485     if (!change)
1486         change = memcmp(ue->tlv_data, container, size) != 0;
1487     if (!change) {
1488         kvfree(container);
1489         return 0;
1490     }
1491
1492     if (ue->tlv_data == NULL) {
1493         /* Now TLV data is available. */
1494         for (i = 0; i < kctl->count; ++i)
1495             kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1496         mask = SNDRV_CTL_EVENT_MASK_INFO;
1497     } else {
1498         ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1499         ue->tlv_data_size = 0;
1500         kvfree(ue->tlv_data);
1501     }
1502
1503     ue->tlv_data = container;
1504     ue->tlv_data_size = size;
1505     // decremented at private_free.
1506     ue->card->user_ctl_alloc_size += size;
1507
1508     mask |= SNDRV_CTL_EVENT_MASK_TLV;
1509     for (i = 0; i < kctl->count; ++i)
1510         snd_ctl_notify_one(ue->card, mask, kctl, i);
1511
1512     return change;
1513 }
1514
1515 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1516              unsigned int size)
1517 {
1518     struct user_element *ue = kctl->private_data;
1519
1520     if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1521         return -ENXIO;
1522
1523     if (size < ue->tlv_data_size)
1524         return -ENOSPC;
1525
1526     if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1527         return -EFAULT;
1528
1529     return 0;
1530 }
1531
1532 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1533                  unsigned int size, unsigned int __user *buf)
1534 {
1535     if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1536         return replace_user_tlv(kctl, buf, size);
1537     else
1538         return read_user_tlv(kctl, buf, size);
1539 }
1540
1541 /* called in controls_rwsem write lock */
1542 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1543 {
1544     char *names, *p;
1545     size_t buf_len, name_len;
1546     unsigned int i;
1547     const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1548
1549     buf_len = ue->info.value.enumerated.names_length;
1550     if (buf_len > 64 * 1024)
1551         return -EINVAL;
1552
1553     if (check_user_elem_overflow(ue->card, buf_len))
1554         return -ENOMEM;
1555     names = vmemdup_user((const void __user *)user_ptrval, buf_len);
1556     if (IS_ERR(names))
1557         return PTR_ERR(names);
1558
1559     /* check that there are enough valid names */
1560     p = names;
1561     for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1562         name_len = strnlen(p, buf_len);
1563         if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1564             kvfree(names);
1565             return -EINVAL;
1566         }
1567         p += name_len + 1;
1568         buf_len -= name_len + 1;
1569     }
1570
1571     ue->priv_data = names;
1572     ue->info.value.enumerated.names_ptr = 0;
1573     // increment the allocation size; decremented again at private_free.
1574     ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
1575
1576     return 0;
1577 }
1578
1579 static size_t compute_user_elem_size(size_t size, unsigned int count)
1580 {
1581     return sizeof(struct user_element) + size * count;
1582 }
1583
1584 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1585 {
1586     struct user_element *ue = kcontrol->private_data;
1587
1588     // decrement the allocation size.
1589     ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
1590     ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1591     if (ue->priv_data)
1592         ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
1593
1594     kvfree(ue->tlv_data);
1595     kvfree(ue->priv_data);
1596     kfree(ue);
1597 }
1598
1599 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1600                 struct snd_ctl_elem_info *info, int replace)
1601 {
1602     struct snd_card *card = file->card;
1603     struct snd_kcontrol *kctl;
1604     unsigned int count;
1605     unsigned int access;
1606     long private_size;
1607     size_t alloc_size;
1608     struct user_element *ue;
1609     unsigned int offset;
1610     int err;
1611
1612     if (!*info->id.name)
1613         return -EINVAL;
1614     if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1615         return -EINVAL;
1616
1617     /* Delete a control to replace them if needed. */
1618     if (replace) {
1619         info->id.numid = 0;
1620         err = snd_ctl_remove_user_ctl(file, &info->id);
1621         if (err)
1622             return err;
1623     }
1624
1625     /* Check the number of elements for this userspace control. */
1626     count = info->owner;
1627     if (count == 0)
1628         count = 1;
1629
1630     /* Arrange access permissions if needed. */
1631     access = info->access;
1632     if (access == 0)
1633         access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1634     access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1635            SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1636            SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1637
1638     /* In initial state, nothing is available as TLV container. */
1639     if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1640         access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1641     access |= SNDRV_CTL_ELEM_ACCESS_USER;
1642
1643     /*
1644      * Check information and calculate the size of data specific to
1645      * this userspace control.
1646      */
1647     /* pass NULL to card for suppressing error messages */
1648     err = snd_ctl_check_elem_info(NULL, info);
1649     if (err < 0)
1650         return err;
1651     /* user-space control doesn't allow zero-size data */
1652     if (info->count < 1)
1653         return -EINVAL;
1654     private_size = value_sizes[info->type] * info->count;
1655     alloc_size = compute_user_elem_size(private_size, count);
1656
1657     down_write(&card->controls_rwsem);
1658     if (check_user_elem_overflow(card, alloc_size)) {
1659         err = -ENOMEM;
1660         goto unlock;
1661     }
1662
1663     /*
1664      * Keep memory object for this userspace control. After passing this
1665      * code block, the instance should be freed by snd_ctl_free_one().
1666      *
1667      * Note that these elements in this control are locked.
1668      */
1669     err = snd_ctl_new(&kctl, count, access, file);
1670     if (err < 0)
1671         goto unlock;
1672     memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1673     ue = kzalloc(alloc_size, GFP_KERNEL);
1674     if (!ue) {
1675         kfree(kctl);
1676         err = -ENOMEM;
1677         goto unlock;
1678     }
1679     kctl->private_data = ue;
1680     kctl->private_free = snd_ctl_elem_user_free;
1681
1682     // increment the allocated size; decremented again at private_free.
1683     card->user_ctl_alloc_size += alloc_size;
1684
1685     /* Set private data for this userspace control. */
1686     ue->card = card;
1687     ue->info = *info;
1688     ue->info.access = 0;
1689     ue->elem_data = (char *)ue + sizeof(*ue);
1690     ue->elem_data_size = private_size;
1691     if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1692         err = snd_ctl_elem_init_enum_names(ue);
1693         if (err < 0) {
1694             snd_ctl_free_one(kctl);
1695             goto unlock;
1696         }
1697     }
1698
1699     /* Set callback functions. */
1700     if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1701         kctl->info = snd_ctl_elem_user_enum_info;
1702     else
1703         kctl->info = snd_ctl_elem_user_info;
1704     if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1705         kctl->get = snd_ctl_elem_user_get;
1706     if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1707         kctl->put = snd_ctl_elem_user_put;
1708     if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1709         kctl->tlv.c = snd_ctl_elem_user_tlv;
1710
1711     /* This function manage to free the instance on failure. */
1712     err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1713     if (err < 0) {
1714         snd_ctl_free_one(kctl);
1715         goto unlock;
1716     }
1717     offset = snd_ctl_get_ioff(kctl, &info->id);
1718     snd_ctl_build_ioff(&info->id, kctl, offset);
1719     /*
1720      * Here we cannot fill any field for the number of elements added by
1721      * this operation because there're no specific fields. The usage of
1722      * 'owner' field for this purpose may cause any bugs to userspace
1723      * applications because the field originally means PID of a process
1724      * which locks the element.
1725      */
1726  unlock:
1727     up_write(&card->controls_rwsem);
1728     return err;
1729 }
1730
1731 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1732                  struct snd_ctl_elem_info __user *_info, int replace)
1733 {
1734     struct snd_ctl_elem_info info;
1735     int err;
1736
1737     if (copy_from_user(&info, _info, sizeof(info)))
1738         return -EFAULT;
1739     err = snd_ctl_elem_add(file, &info, replace);
1740     if (err < 0)
1741         return err;
1742     if (copy_to_user(_info, &info, sizeof(info))) {
1743         snd_ctl_remove_user_ctl(file, &info.id);
1744         return -EFAULT;
1745     }
1746
1747     return 0;
1748 }
1749
1750 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1751                    struct snd_ctl_elem_id __user *_id)
1752 {
1753     struct snd_ctl_elem_id id;
1754
1755     if (copy_from_user(&id, _id, sizeof(id)))
1756         return -EFAULT;
1757     return snd_ctl_remove_user_ctl(file, &id);
1758 }
1759
1760 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1761 {
1762     int subscribe;
1763     if (get_user(subscribe, ptr))
1764         return -EFAULT;
1765     if (subscribe < 0) {
1766         subscribe = file->subscribed;
1767         if (put_user(subscribe, ptr))
1768             return -EFAULT;
1769         return 0;
1770     }
1771     if (subscribe) {
1772         file->subscribed = 1;
1773         return 0;
1774     } else if (file->subscribed) {
1775         snd_ctl_empty_read_queue(file);
1776         file->subscribed = 0;
1777     }
1778     return 0;
1779 }
1780
1781 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1782                 struct snd_kcontrol *kctl,
1783                 struct snd_ctl_elem_id *id,
1784                 unsigned int __user *buf, unsigned int size)
1785 {
1786     static const struct {
1787         int op;
1788         int perm;
1789     } pairs[] = {
1790         {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1791         {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1792         {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1793     };
1794     struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1795     int i, ret;
1796
1797     /* Check support of the request for this element. */
1798     for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1799         if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1800             break;
1801     }
1802     if (i == ARRAY_SIZE(pairs))
1803         return -ENXIO;
1804
1805     if (kctl->tlv.c == NULL)
1806         return -ENXIO;
1807
1808     /* Write and command operations are not allowed for locked element. */
1809     if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1810         vd->owner != NULL && vd->owner != file)
1811         return -EPERM;
1812
1813     ret = snd_power_ref_and_wait(file->card);
1814     if (!ret)
1815         ret = kctl->tlv.c(kctl, op_flag, size, buf);
1816     snd_power_unref(file->card);
1817     return ret;
1818 }
1819
1820 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1821             unsigned int __user *buf, unsigned int size)
1822 {
1823     struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1824     unsigned int len;
1825
1826     if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1827         return -ENXIO;
1828
1829     if (kctl->tlv.p == NULL)
1830         return -ENXIO;
1831
1832     len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1833     if (size < len)
1834         return -ENOMEM;
1835
1836     if (copy_to_user(buf, kctl->tlv.p, len))
1837         return -EFAULT;
1838
1839     return 0;
1840 }
1841
1842 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1843                  struct snd_ctl_tlv __user *buf,
1844                              int op_flag)
1845 {
1846     struct snd_ctl_tlv header;
1847     unsigned int __user *container;
1848     unsigned int container_size;
1849     struct snd_kcontrol *kctl;
1850     struct snd_ctl_elem_id id;
1851     struct snd_kcontrol_volatile *vd;
1852
1853     if (copy_from_user(&header, buf, sizeof(header)))
1854         return -EFAULT;
1855
1856     /* In design of control core, numerical ID starts at 1. */
1857     if (header.numid == 0)
1858         return -EINVAL;
1859
1860     /* At least, container should include type and length fields.  */
1861     if (header.length < sizeof(unsigned int) * 2)
1862         return -EINVAL;
1863     container_size = header.length;
1864     container = buf->tlv;
1865
1866     kctl = snd_ctl_find_numid(file->card, header.numid);
1867     if (kctl == NULL)
1868         return -ENOENT;
1869
1870     /* Calculate index of the element in this set. */
1871     id = kctl->id;
1872     snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1873     vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1874
1875     if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1876         return call_tlv_handler(file, op_flag, kctl, &id, container,
1877                     container_size);
1878     } else {
1879         if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1880             return read_tlv_buf(kctl, &id, container,
1881                         container_size);
1882         }
1883     }
1884
1885     /* Not supported. */
1886     return -ENXIO;
1887 }
1888
1889 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1890 {
1891     struct snd_ctl_file *ctl;
1892     struct snd_card *card;
1893     struct snd_kctl_ioctl *p;
1894     void __user *argp = (void __user *)arg;
1895     int __user *ip = argp;
1896     int err;
1897
1898     ctl = file->private_data;
1899     card = ctl->card;
1900     if (snd_BUG_ON(!card))
1901         return -ENXIO;
1902     switch (cmd) {
1903     case SNDRV_CTL_IOCTL_PVERSION:
1904         return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1905     case SNDRV_CTL_IOCTL_CARD_INFO:
1906         return snd_ctl_card_info(card, ctl, cmd, argp);
1907     case SNDRV_CTL_IOCTL_ELEM_LIST:
1908         return snd_ctl_elem_list_user(card, argp);
1909     case SNDRV_CTL_IOCTL_ELEM_INFO:
1910         return snd_ctl_elem_info_user(ctl, argp);
1911     case SNDRV_CTL_IOCTL_ELEM_READ:
1912         return snd_ctl_elem_read_user(card, argp);
1913     case SNDRV_CTL_IOCTL_ELEM_WRITE:
1914         return snd_ctl_elem_write_user(ctl, argp);
1915     case SNDRV_CTL_IOCTL_ELEM_LOCK:
1916         return snd_ctl_elem_lock(ctl, argp);
1917     case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1918         return snd_ctl_elem_unlock(ctl, argp);
1919     case SNDRV_CTL_IOCTL_ELEM_ADD:
1920         return snd_ctl_elem_add_user(ctl, argp, 0);
1921     case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1922         return snd_ctl_elem_add_user(ctl, argp, 1);
1923     case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1924         return snd_ctl_elem_remove(ctl, argp);
1925     case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1926         return snd_ctl_subscribe_events(ctl, ip);
1927     case SNDRV_CTL_IOCTL_TLV_READ:
1928         down_read(&ctl->card->controls_rwsem);
1929         err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1930         up_read(&ctl->card->controls_rwsem);
1931         return err;
1932     case SNDRV_CTL_IOCTL_TLV_WRITE:
1933         down_write(&ctl->card->controls_rwsem);
1934         err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1935         up_write(&ctl->card->controls_rwsem);
1936         return err;
1937     case SNDRV_CTL_IOCTL_TLV_COMMAND:
1938         down_write(&ctl->card->controls_rwsem);
1939         err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1940         up_write(&ctl->card->controls_rwsem);
1941         return err;
1942     case SNDRV_CTL_IOCTL_POWER:
1943         return -ENOPROTOOPT;
1944     case SNDRV_CTL_IOCTL_POWER_STATE:
1945         return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1946     }
1947     down_read(&snd_ioctl_rwsem);
1948     list_for_each_entry(p, &snd_control_ioctls, list) {
1949         err = p->fioctl(card, ctl, cmd, arg);
1950         if (err != -ENOIOCTLCMD) {
1951             up_read(&snd_ioctl_rwsem);
1952             return err;
1953         }
1954     }
1955     up_read(&snd_ioctl_rwsem);
1956     dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1957     return -ENOTTY;
1958 }
1959
1960 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1961                 size_t count, loff_t * offset)
1962 {
1963     struct snd_ctl_file *ctl;
1964     int err = 0;
1965     ssize_t result = 0;
1966
1967     ctl = file->private_data;
1968     if (snd_BUG_ON(!ctl || !ctl->card))
1969         return -ENXIO;
1970     if (!ctl->subscribed)
1971         return -EBADFD;
1972     if (count < sizeof(struct snd_ctl_event))
1973         return -EINVAL;
1974     spin_lock_irq(&ctl->read_lock);
1975     while (count >= sizeof(struct snd_ctl_event)) {
1976         struct snd_ctl_event ev;
1977         struct snd_kctl_event *kev;
1978         while (list_empty(&ctl->events)) {
1979             wait_queue_entry_t wait;
1980             if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1981                 err = -EAGAIN;
1982                 goto __end_lock;
1983             }
1984             init_waitqueue_entry(&wait, current);
1985             add_wait_queue(&ctl->change_sleep, &wait);
1986             set_current_state(TASK_INTERRUPTIBLE);
1987             spin_unlock_irq(&ctl->read_lock);
1988             schedule();
1989             remove_wait_queue(&ctl->change_sleep, &wait);
1990             if (ctl->card->shutdown)
1991                 return -ENODEV;
1992             if (signal_pending(current))
1993                 return -ERESTARTSYS;
1994             spin_lock_irq(&ctl->read_lock);
1995         }
1996         kev = snd_kctl_event(ctl->events.next);
1997         ev.type = SNDRV_CTL_EVENT_ELEM;
1998         ev.data.elem.mask = kev->mask;
1999         ev.data.elem.id = kev->id;
2000         list_del(&kev->list);
2001         spin_unlock_irq(&ctl->read_lock);
2002         kfree(kev);
2003         if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
2004             err = -EFAULT;
2005             goto __end;
2006         }
2007         spin_lock_irq(&ctl->read_lock);
2008         buffer += sizeof(struct snd_ctl_event);
2009         count -= sizeof(struct snd_ctl_event);
2010         result += sizeof(struct snd_ctl_event);
2011     }
2012       __end_lock:
2013     spin_unlock_irq(&ctl->read_lock);
2014       __end:
2015         return result > 0 ? result : err;
2016 }
2017
2018 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
2019 {
2020     __poll_t mask;
2021     struct snd_ctl_file *ctl;
2022
2023     ctl = file->private_data;
2024     if (!ctl->subscribed)
2025         return 0;
2026     poll_wait(file, &ctl->change_sleep, wait);
2027
2028     mask = 0;
2029     if (!list_empty(&ctl->events))
2030         mask |= EPOLLIN | EPOLLRDNORM;
2031
2032     return mask;
2033 }
2034
2035 /*
2036  * register the device-specific control-ioctls.
2037  * called from each device manager like pcm.c, hwdep.c, etc.
2038  */
2039 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
2040 {
2041     struct snd_kctl_ioctl *pn;
2042
2043     pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
2044     if (pn == NULL)
2045         return -ENOMEM;
2046     pn->fioctl = fcn;
2047     down_write(&snd_ioctl_rwsem);
2048     list_add_tail(&pn->list, lists);
2049     up_write(&snd_ioctl_rwsem);
2050     return 0;
2051 }
2052
2053 /**
2054  * snd_ctl_register_ioctl - register the device-specific control-ioctls
2055  * @fcn: ioctl callback function
2056  *
2057  * called from each device manager like pcm.c, hwdep.c, etc.
2058  *
2059  * Return: zero if successful, or a negative error code
2060  */
2061 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
2062 {
2063     return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
2064 }
2065 EXPORT_SYMBOL(snd_ctl_register_ioctl);
2066
2067 #ifdef CONFIG_COMPAT
2068 /**
2069  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
2070  * control-ioctls
2071  * @fcn: ioctl callback function
2072  *
2073  * Return: zero if successful, or a negative error code
2074  */
2075 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2076 {
2077     return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
2078 }
2079 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
2080 #endif
2081
2082 /*
2083  * de-register the device-specific control-ioctls.
2084  */
2085 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
2086                      struct list_head *lists)
2087 {
2088     struct snd_kctl_ioctl *p;
2089
2090     if (snd_BUG_ON(!fcn))
2091         return -EINVAL;
2092     down_write(&snd_ioctl_rwsem);
2093     list_for_each_entry(p, lists, list) {
2094         if (p->fioctl == fcn) {
2095             list_del(&p->list);
2096             up_write(&snd_ioctl_rwsem);
2097             kfree(p);
2098             return 0;
2099         }
2100     }
2101     up_write(&snd_ioctl_rwsem);
2102     snd_BUG();
2103     return -EINVAL;
2104 }
2105
2106 /**
2107  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
2108  * @fcn: ioctl callback function to unregister
2109  *
2110  * Return: zero if successful, or a negative error code
2111  */
2112 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
2113 {
2114     return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
2115 }
2116 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
2117
2118 #ifdef CONFIG_COMPAT
2119 /**
2120  * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
2121  * 32bit control-ioctls
2122  * @fcn: ioctl callback function to unregister
2123  *
2124  * Return: zero if successful, or a negative error code
2125  */
2126 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2127 {
2128     return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
2129 }
2130 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
2131 #endif
2132
2133 static int snd_ctl_fasync(int fd, struct file * file, int on)
2134 {
2135     struct snd_ctl_file *ctl;
2136
2137     ctl = file->private_data;
2138     return snd_fasync_helper(fd, file, on, &ctl->fasync);
2139 }
2140
2141 /* return the preferred subdevice number if already assigned;
2142  * otherwise return -1
2143  */
2144 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
2145 {
2146     struct snd_ctl_file *kctl;
2147     int subdevice = -1;
2148     unsigned long flags;
2149
2150     read_lock_irqsave(&card->ctl_files_rwlock, flags);
2151     list_for_each_entry(kctl, &card->ctl_files, list) {
2152         if (kctl->pid == task_pid(current)) {
2153             subdevice = kctl->preferred_subdevice[type];
2154             if (subdevice != -1)
2155                 break;
2156         }
2157     }
2158     read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2159     return subdevice;
2160 }
2161 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
2162
2163 /*
2164  * ioctl32 compat
2165  */
2166 #ifdef CONFIG_COMPAT
2167 #include "control_compat.c"
2168 #else
2169 #define snd_ctl_ioctl_compat    NULL
2170 #endif
2171
2172 /*
2173  * control layers (audio LED etc.)
2174  */
2175
2176 /**
2177  * snd_ctl_request_layer - request to use the layer
2178  * @module_name: Name of the kernel module (NULL == build-in)
2179  *
2180  * Return: zero if successful, or an error code when the module cannot be loaded
2181  */
2182 int snd_ctl_request_layer(const char *module_name)
2183 {
2184     struct snd_ctl_layer_ops *lops;
2185
2186     if (module_name == NULL)
2187         return 0;
2188     down_read(&snd_ctl_layer_rwsem);
2189     for (lops = snd_ctl_layer; lops; lops = lops->next)
2190         if (strcmp(lops->module_name, module_name) == 0)
2191             break;
2192     up_read(&snd_ctl_layer_rwsem);
2193     if (lops)
2194         return 0;
2195     return request_module(module_name);
2196 }
2197 EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
2198
2199 /**
2200  * snd_ctl_register_layer - register new control layer
2201  * @lops: operation structure
2202  *
2203  * The new layer can track all control elements and do additional
2204  * operations on top (like audio LED handling).
2205  */
2206 void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
2207 {
2208     struct snd_card *card;
2209     int card_number;
2210
2211     down_write(&snd_ctl_layer_rwsem);
2212     lops->next = snd_ctl_layer;
2213     snd_ctl_layer = lops;
2214     up_write(&snd_ctl_layer_rwsem);
2215     for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
2216         card = snd_card_ref(card_number);
2217         if (card) {
2218             down_read(&card->controls_rwsem);
2219             lops->lregister(card);
2220             up_read(&card->controls_rwsem);
2221             snd_card_unref(card);
2222         }
2223     }
2224 }
2225 EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
2226
2227 /**
2228  * snd_ctl_disconnect_layer - disconnect control layer
2229  * @lops: operation structure
2230  *
2231  * It is expected that the information about tracked cards
2232  * is freed before this call (the disconnect callback is
2233  * not called here).
2234  */
2235 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
2236 {
2237     struct snd_ctl_layer_ops *lops2, *prev_lops2;
2238
2239     down_write(&snd_ctl_layer_rwsem);
2240     for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
2241         if (lops2 == lops) {
2242             if (!prev_lops2)
2243                 snd_ctl_layer = lops->next;
2244             else
2245                 prev_lops2->next = lops->next;
2246             break;
2247         }
2248         prev_lops2 = lops2;
2249     }
2250     up_write(&snd_ctl_layer_rwsem);
2251 }
2252 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
2253
2254 /*
2255  *  INIT PART
2256  */
2257
2258 static const struct file_operations snd_ctl_f_ops =
2259 {
2260     .owner =    THIS_MODULE,
2261     .read =     snd_ctl_read,
2262     .open =     snd_ctl_open,
2263     .release =  snd_ctl_release,
2264     .llseek =   no_llseek,
2265     .poll =     snd_ctl_poll,
2266     .unlocked_ioctl =   snd_ctl_ioctl,
2267     .compat_ioctl = snd_ctl_ioctl_compat,
2268     .fasync =   snd_ctl_fasync,
2269 };
2270
2271 /*
2272  * registration of the control device
2273  */
2274 static int snd_ctl_dev_register(struct snd_device *device)
2275 {
2276     struct snd_card *card = device->device_data;
2277     struct snd_ctl_layer_ops *lops;
2278     int err;
2279
2280     err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2281                   &snd_ctl_f_ops, card, &card->ctl_dev);
2282     if (err < 0)
2283         return err;
2284     down_read(&card->controls_rwsem);
2285     down_read(&snd_ctl_layer_rwsem);
2286     for (lops = snd_ctl_layer; lops; lops = lops->next)
2287         lops->lregister(card);
2288     up_read(&snd_ctl_layer_rwsem);
2289     up_read(&card->controls_rwsem);
2290     return 0;
2291 }
2292
2293 /*
2294  * disconnection of the control device
2295  */
2296 static int snd_ctl_dev_disconnect(struct snd_device *device)
2297 {
2298     struct snd_card *card = device->device_data;
2299     struct snd_ctl_file *ctl;
2300     struct snd_ctl_layer_ops *lops;
2301     unsigned long flags;
2302
2303     read_lock_irqsave(&card->ctl_files_rwlock, flags);
2304     list_for_each_entry(ctl, &card->ctl_files, list) {
2305         wake_up(&ctl->change_sleep);
2306         snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
2307     }
2308     read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2309
2310     down_read(&card->controls_rwsem);
2311     down_read(&snd_ctl_layer_rwsem);
2312     for (lops = snd_ctl_layer; lops; lops = lops->next)
2313         lops->ldisconnect(card);
2314     up_read(&snd_ctl_layer_rwsem);
2315     up_read(&card->controls_rwsem);
2316
2317     return snd_unregister_device(&card->ctl_dev);
2318 }
2319
2320 /*
2321  * free all controls
2322  */
2323 static int snd_ctl_dev_free(struct snd_device *device)
2324 {
2325     struct snd_card *card = device->device_data;
2326     struct snd_kcontrol *control;
2327
2328     down_write(&card->controls_rwsem);
2329     while (!list_empty(&card->controls)) {
2330         control = snd_kcontrol(card->controls.next);
2331         __snd_ctl_remove(card, control, false);
2332     }
2333
2334 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
2335     xa_destroy(&card->ctl_numids);
2336     xa_destroy(&card->ctl_hash);
2337 #endif
2338     up_write(&card->controls_rwsem);
2339     put_device(&card->ctl_dev);
2340     return 0;
2341 }
2342
2343 /*
2344  * create control core:
2345  * called from init.c
2346  */
2347 int snd_ctl_create(struct snd_card *card)
2348 {
2349     static const struct snd_device_ops ops = {
2350         .dev_free = snd_ctl_dev_free,
2351         .dev_register = snd_ctl_dev_register,
2352         .dev_disconnect = snd_ctl_dev_disconnect,
2353     };
2354     int err;
2355
2356     if (snd_BUG_ON(!card))
2357         return -ENXIO;
2358     if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2359         return -ENXIO;
2360
2361     snd_device_initialize(&card->ctl_dev, card);
2362     dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2363
2364     err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2365     if (err < 0)
2366         put_device(&card->ctl_dev);
2367     return err;
2368 }
2369
2370 /*
2371  * Frequently used control callbacks/helpers
2372  */
2373
2374 /**
2375  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2376  * callback with a mono channel
2377  * @kcontrol: the kcontrol instance
2378  * @uinfo: info to store
2379  *
2380  * This is a function that can be used as info callback for a standard
2381  * boolean control with a single mono channel.
2382  *
2383  * Return: Zero (always successful)
2384  */
2385 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2386                   struct snd_ctl_elem_info *uinfo)
2387 {
2388     uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2389     uinfo->count = 1;
2390     uinfo->value.integer.min = 0;
2391     uinfo->value.integer.max = 1;
2392     return 0;
2393 }
2394 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2395
2396 /**
2397  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2398  * callback with stereo two channels
2399  * @kcontrol: the kcontrol instance
2400  * @uinfo: info to store
2401  *
2402  * This is a function that can be used as info callback for a standard
2403  * boolean control with stereo two channels.
2404  *
2405  * Return: Zero (always successful)
2406  */
2407 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2408                 struct snd_ctl_elem_info *uinfo)
2409 {
2410     uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2411     uinfo->count = 2;
2412     uinfo->value.integer.min = 0;
2413     uinfo->value.integer.max = 1;
2414     return 0;
2415 }
2416 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2417
2418 /**
2419  * snd_ctl_enum_info - fills the info structure for an enumerated control
2420  * @info: the structure to be filled
2421  * @channels: the number of the control's channels; often one
2422  * @items: the number of control values; also the size of @names
2423  * @names: an array containing the names of all control values
2424  *
2425  * Sets all required fields in @info to their appropriate values.
2426  * If the control's accessibility is not the default (readable and writable),
2427  * the caller has to fill @info->access.
2428  *
2429  * Return: Zero (always successful)
2430  */
2431 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2432               unsigned int items, const char *const names[])
2433 {
2434     info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2435     info->count = channels;
2436     info->value.enumerated.items = items;
2437     if (!items)
2438         return 0;
2439     if (info->value.enumerated.item >= items)
2440         info->value.enumerated.item = items - 1;
2441     WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2442          "ALSA: too long item name '%s'\n",
2443          names[info->value.enumerated.item]);
2444     strscpy(info->value.enumerated.name,
2445         names[info->value.enumerated.item],
2446         sizeof(info->value.enumerated.name));
2447     return 0;
2448 }
2449 EXPORT_SYMBOL(snd_ctl_enum_info);