// SPDX-License-Identifier: GPL-2.0-or-later/* * Routines for driver control interface * Copyright (c) by Jaroslav Kysela <perex@perex.cz> */ #include <linux/threads.h>#include <linux/interrupt.h>#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/slab.h>#include <linux/vmalloc.h>#include <linux/time.h>#include <linux/mm.h>#include <linux/math64.h>#include <linux/sched/signal.h>#include <sound/core.h>#include <sound/minors.h>#include <sound/info.h>#include <sound/control.h> #ifdef CONFIG_SND_CTL_DEBUG#define CREATE_TRACE_POINTS#include "control_trace.h"#else#define trace_snd_ctl_put(card, kctl, iname, expected, actual)#endif // Max allocation size for user controls.static int max_user_ctl_alloc_size = 8 * 1024 * 1024;module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls"); #define MAX_CONTROL_COUNT 1028 struct snd_kctl_ioctl { struct list_head list; /* list of all ioctls */ snd_kctl_ioctl_func_t fioctl;}; DECLARE_RWSEM(snd_ioctl_rwsem);static DECLARE_RWSEM(snd_ctl_layer_rwsem);static LIST_HEAD(snd_control_ioctls);#ifdef CONFIG_COMPATstatic LIST_HEAD(snd_control_compat_ioctls);#endifstatic struct snd_ctl_layer_ops *snd_ctl_layer; static int snd_ctl_remove_locked(struct snd_card *card, struct snd_kcontrol *kcontrol); static int snd_ctl_open(struct inode *inode, struct file *file){ struct snd_card *card; struct snd_ctl_file *ctl; int i, err; stream_open(inode, file); card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL); if (!card) { err = -ENODEV; goto __error1; } err = snd_card_file_add(card, file); if (err < 0) goto __error1; if (!try_module_get(card->module)) { err = -ENODEV; goto __error2; } ctl = kzalloc_obj(*ctl); if (ctl == NULL) { err = -ENOMEM; goto __error; } INIT_LIST_HEAD(&ctl->events); init_waitqueue_head(&ctl->change_sleep); spin_lock_init(&ctl->read_lock); ctl->card = card; for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++) ctl->preferred_subdevice[i] = -1; ctl->pid = get_pid(task_pid(current)); file->private_data = ctl; scoped_guard(write_lock_irqsave, &card->controls_rwlock) list_add_tail(&ctl->list, &card->ctl_files); snd_card_unref(card); return 0; __error: module_put(card->module); __error2: snd_card_file_remove(card, file); __error1: if (card) snd_card_unref(card); return err;} static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl){ struct snd_kctl_event *cread; guard(spinlock_irqsave)(&ctl->read_lock); while (!list_empty(&ctl->events)) { cread = snd_kctl_event(ctl->events.next); list_del(&cread->list); kfree(cread); }} static int snd_ctl_release(struct inode *inode, struct file *file){ struct snd_card *card; struct snd_ctl_file *ctl; struct snd_kcontrol *control; unsigned int idx; ctl = file->private_data; file->private_data = NULL; card = ctl->card; scoped_guard(write_lock_irqsave, &card->controls_rwlock) list_del(&ctl->list); scoped_guard(rwsem_write, &card->controls_rwsem) { list_for_each_entry(control, &card->controls, list) for (idx = 0; idx < control->count; idx++) if (control->vd[idx].owner == ctl) control->vd[idx].owner = NULL; } snd_fasync_free(ctl->fasync); snd_ctl_empty_read_queue(ctl); put_pid(ctl->pid); kfree(ctl); module_put(card->module); snd_card_file_remove(card, file); return 0;} /** * snd_ctl_notify - Send notification to user-space for a control change * @card: the card to send notification * @mask: the event mask, SNDRV_CTL_EVENT_* * @id: the ctl element id to send notification * * This function adds an event record with the given id and mask, appends * to the list and wakes up the user-space for notification. This can be * called in the atomic context. */void snd_ctl_notify(struct snd_card *card, unsigned int mask, struct snd_ctl_elem_id *id){ struct snd_ctl_file *ctl; struct snd_kctl_event *ev; if (snd_BUG_ON(!card || !id)) return; if (card->shutdown) return; guard(read_lock_irqsave)(&card->controls_rwlock);#if IS_ENABLED(CONFIG_SND_MIXER_OSS) card->mixer_oss_change_count++;#endif list_for_each_entry(ctl, &card->ctl_files, list) { if (!ctl->subscribed) continue; scoped_guard(spinlock, &ctl->read_lock) { list_for_each_entry(ev, &ctl->events, list) { if (ev->id.numid == id->numid) { ev->mask |= mask; goto _found; } } ev = kzalloc_obj(*ev, GFP_ATOMIC); if (ev) { ev->id = *id; ev->mask = mask; list_add_tail(&ev->list, &ctl->events); } else { dev_err(card->dev, "No memory available to allocate event\n"); }_found: wake_up(&ctl->change_sleep); } snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN); }}EXPORT_SYMBOL(snd_ctl_notify); /** * snd_ctl_notify_one - Send notification to user-space for a control change * @card: the card to send notification * @mask: the event mask, SNDRV_CTL_EVENT_* * @kctl: the pointer with the control instance * @ioff: the additional offset to the control index * * This function calls snd_ctl_notify() and does additional jobs * like LED state changes. */void snd_ctl_notify_one(struct snd_card *card, unsigned int mask, struct snd_kcontrol *kctl, unsigned int ioff){ struct snd_ctl_elem_id id = kctl->id; struct snd_ctl_layer_ops *lops; id.index += ioff; id.numid += ioff; snd_ctl_notify(card, mask, &id); guard(rwsem_read)(&snd_ctl_layer_rwsem); for (lops = snd_ctl_layer; lops; lops = lops->next) lops->lnotify(card, mask, kctl, ioff);}EXPORT_SYMBOL(snd_ctl_notify_one); /** * snd_ctl_new - create a new control instance with some elements * @kctl: the pointer to store new control instance * @count: the number of elements in this control * @access: the default access flags for elements in this control * @file: given when locking these elements * * Allocates a memory object for a new control instance. The instance has * elements as many as the given number (@count). Each element has given * access permissions (@access). Each element is locked when @file is given. * * Return: 0 on success, error code on failure */static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count, unsigned int access, struct snd_ctl_file *file){ unsigned int idx; if (count == 0 || count > MAX_CONTROL_COUNT) return -EINVAL; *kctl = kzalloc_flex(**kctl, vd, count); if (!*kctl) return -ENOMEM; (*kctl)->count = count; for (idx = 0; idx < count; idx++) { (*kctl)->vd[idx].access = access; (*kctl)->vd[idx].owner = file; } return 0;} /** * snd_ctl_new1 - create a control instance from the template * @ncontrol: the initialization record * @private_data: the private data to set * * Allocates a new struct snd_kcontrol instance and initialize from the given * template. When the access field of ncontrol is 0, it's assumed as * READWRITE access. When the count field is 0, it's assumes as one. * * Return: The pointer of the newly generated instance, or %NULL on failure. */struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol, void *private_data){ struct snd_kcontrol *kctl; unsigned int count; unsigned int access; int err; if (snd_BUG_ON(!ncontrol || !ncontrol->info)) return NULL; count = ncontrol->count; if (count == 0) count = 1; access = ncontrol->access; if (access == 0) access = SNDRV_CTL_ELEM_ACCESS_READWRITE; access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_VOLATILE | SNDRV_CTL_ELEM_ACCESS_INACTIVE | SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND | SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK | SNDRV_CTL_ELEM_ACCESS_LED_MASK | SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK); err = snd_ctl_new(&kctl, count, access, NULL); if (err < 0) return NULL; /* The 'numid' member is decided when calling snd_ctl_add(). */ kctl->id.iface = ncontrol->iface; kctl->id.device = ncontrol->device; kctl->id.subdevice = ncontrol->subdevice; if (ncontrol->name) { strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name)); if (strcmp(ncontrol->name, kctl->id.name) != 0) pr_warn("ALSA: Control name '%s' truncated to '%s'\n", ncontrol->name, kctl->id.name); } kctl->id.index = ncontrol->index; kctl->info = ncontrol->info; kctl->get = ncontrol->get; kctl->put = ncontrol->put; kctl->tlv.p = ncontrol->tlv.p; kctl->private_value = ncontrol->private_value; kctl->private_data = private_data; return kctl;}EXPORT_SYMBOL(snd_ctl_new1); /** * snd_ctl_free_one - release the control instance * @kcontrol: the control instance * * Releases the control instance created via snd_ctl_new() * or snd_ctl_new1(). * Don't call this after the control was added to the card. */void snd_ctl_free_one(struct snd_kcontrol *kcontrol){ if (kcontrol) { if (kcontrol->private_free) kcontrol->private_free(kcontrol); kfree(kcontrol); }}EXPORT_SYMBOL(snd_ctl_free_one); static bool snd_ctl_remove_numid_conflict(struct snd_card *card, unsigned int count){ struct snd_kcontrol *kctl; /* Make sure that the ids assigned to the control do not wrap around */ if (card->last_numid >= UINT_MAX - count) card->last_numid = 0; list_for_each_entry(kctl, &card->controls, list) { if (kctl->id.numid < card->last_numid + 1 + count && kctl->id.numid + kctl->count > card->last_numid + 1) { card->last_numid = kctl->id.numid + kctl->count - 1; return true; } } return false;} static int snd_ctl_find_hole(struct snd_card *card, unsigned int count){ unsigned int iter = 100000; while (snd_ctl_remove_numid_conflict(card, count)) { if (--iter == 0) { /* this situation is very unlikely */ dev_err(card->dev, "unable to allocate new control numid\n"); return -ENOMEM; } } return 0;} /* check whether the given id is contained in the given kctl */static bool elem_id_matches(const struct snd_kcontrol *kctl, const struct snd_ctl_elem_id *id){ return kctl->id.iface == id->iface && kctl->id.device == id->device && kctl->id.subdevice == id->subdevice && !strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) && kctl->id.index <= id->index && kctl->id.index + kctl->count > id->index;} #ifdef CONFIG_SND_CTL_FAST_LOOKUP/* Compute a hash key for the corresponding ctl id * It's for the name lookup, hence the numid is excluded. * The hash key is bound in LONG_MAX to be used for Xarray key. */#define MULTIPLIER 37static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id){ int i; unsigned long h; h = id->iface; h = MULTIPLIER * h + id->device; h = MULTIPLIER * h + id->subdevice; for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++) h = MULTIPLIER * h + id->name[i]; h = MULTIPLIER * h + id->index; h &= LONG_MAX; return h;} /* add hash entries to numid and ctl xarray tables */static void add_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol){ struct snd_ctl_elem_id id = kcontrol->id; int i; xa_store_range(&card->ctl_numids, kcontrol->id.numid, kcontrol->id.numid + kcontrol->count - 1, kcontrol, GFP_KERNEL); for (i = 0; i < kcontrol->count; i++) { id.index = kcontrol->id.index + i; if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id), kcontrol, GFP_KERNEL)) { /* skip hash for this entry, noting we had collision */ card->ctl_hash_collision = true; dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n", id.iface, id.name, id.index); } }} /* remove hash entries that have been added */static void remove_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol){ struct snd_ctl_elem_id id = kcontrol->id; struct snd_kcontrol *matched; unsigned long h; int i; for (i = 0; i < kcontrol->count; i++) { xa_erase(&card->ctl_numids, id.numid); h = get_ctl_id_hash(&id); matched = xa_load(&card->ctl_hash, h); if (matched && (matched == kcontrol || elem_id_matches(matched, &id))) xa_erase(&card->ctl_hash, h); id.index++; id.numid++; }}#else /* CONFIG_SND_CTL_FAST_LOOKUP */static inline void add_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol){}static inline void remove_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol){}#endif /* CONFIG_SND_CTL_FAST_LOOKUP */ enum snd_ctl_add_mode { CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,}; /* add/replace a new kcontrol object; call with card->controls_rwsem locked */static int __snd_ctl_add_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, enum snd_ctl_add_mode mode){ struct snd_ctl_elem_id id; unsigned int idx; struct snd_kcontrol *old; int err; lockdep_assert_held_write(&card->controls_rwsem); id = kcontrol->id; if (id.index > UINT_MAX - kcontrol->count) return -EINVAL; old = snd_ctl_find_id(card, &id); if (!old) { if (mode == CTL_REPLACE) return -EINVAL; } else { if (mode == CTL_ADD_EXCLUSIVE) { dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n", id.iface, id.device, id.subdevice, id.name, id.index); return -EBUSY; } err = snd_ctl_remove_locked(card, old); if (err < 0) return err; } if (snd_ctl_find_hole(card, kcontrol->count) < 0) return -ENOMEM; scoped_guard(write_lock_irq, &card->controls_rwlock) { list_add_tail(&kcontrol->list, &card->controls); card->controls_count += kcontrol->count; kcontrol->id.numid = card->last_numid + 1;Lines 1–500 of 2585. 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// SPDX-License-Identifier: GPL-2.0-or-later /* * Routines for driver control interface * Copyright (c) by Jaroslav Kysela <perex@perex.cz> */ #include <linux/threads.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/time.h> #include <linux/mm.h> #include <linux/math64.h> #include <linux/sched/signal.h> #include <sound/core.h> #include <sound/minors.h> #include <sound/info.h> #include <sound/control.h> #ifdef CONFIG_SND_CTL_DEBUG #define CREATE_TRACE_POINTS #include "control_trace.h" #else #define trace_snd_ctl_put(card, kctl, iname, expected, actual) #endif // Max allocation size for user controls. static int max_user_ctl_alloc_size = 8 * 1024 * 1024; module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444); MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls"); #define MAX_CONTROL_COUNT 1028 struct snd_kctl_ioctl { struct list_head list; /* list of all ioctls */ snd_kctl_ioctl_func_t fioctl; }; DECLARE_RWSEM(snd_ioctl_rwsem); static DECLARE_RWSEM(snd_ctl_layer_rwsem); static LIST_HEAD(snd_control_ioctls); #ifdef CONFIG_COMPAT static LIST_HEAD(snd_control_compat_ioctls); #endif static struct snd_ctl_layer_ops *snd_ctl_layer; static int snd_ctl_remove_locked(struct snd_card *card, struct snd_kcontrol *kcontrol); static int snd_ctl_open(struct inode *inode, struct file *file) { struct snd_card *card; struct snd_ctl_file *ctl; int i, err; stream_open(inode, file); card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL); if (!card) { err = -ENODEV; goto __error1; } err = snd_card_file_add(card, file); if (err < 0) goto __error1; if (!try_module_get(card->module)) { err = -ENODEV; goto __error2; } ctl = kzalloc_obj(*ctl); if (ctl == NULL) { err = -ENOMEM; goto __error; } INIT_LIST_HEAD(&ctl->events); init_waitqueue_head(&ctl->change_sleep); spin_lock_init(&ctl->read_lock); ctl->card = card; for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++) ctl->preferred_subdevice[i] = -1; ctl->pid = get_pid(task_pid(current)); file->private_data = ctl; scoped_guard(write_lock_irqsave, &card->controls_rwlock) list_add_tail(&ctl->list, &card->ctl_files); snd_card_unref(card); return 0; __error: module_put(card->module); __error2: snd_card_file_remove(card, file); __error1: if (card) snd_card_unref(card); return err; } static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl) { struct snd_kctl_event *cread; guard(spinlock_irqsave)(&ctl->read_lock); while (!list_empty(&ctl->events)) { cread = snd_kctl_event(ctl->events.next); list_del(&cread->list); kfree(cread); } } static int snd_ctl_release(struct inode *inode, struct file *file) { struct snd_card *card; struct snd_ctl_file *ctl; struct snd_kcontrol *control; unsigned int idx; ctl = file->private_data; file->private_data = NULL; card = ctl->card; scoped_guard(write_lock_irqsave, &card->controls_rwlock) list_del(&ctl->list); scoped_guard(rwsem_write, &card->controls_rwsem) { list_for_each_entry(control, &card->controls, list) for (idx = 0; idx < control->count; idx++) if (control->vd[idx].owner == ctl) control->vd[idx].owner = NULL; } snd_fasync_free(ctl->fasync); snd_ctl_empty_read_queue(ctl); put_pid(ctl->pid); kfree(ctl); module_put(card->module); snd_card_file_remove(card, file); return 0; } /** * snd_ctl_notify - Send notification to user-space for a control change * @card: the card to send notification * @mask: the event mask, SNDRV_CTL_EVENT_* * @id: the ctl element id to send notification * * This function adds an event record with the given id and mask, appends * to the list and wakes up the user-space for notification. This can be * called in the atomic context. */ void snd_ctl_notify(struct snd_card *card, unsigned int mask, struct snd_ctl_elem_id *id) { struct snd_ctl_file *ctl; struct snd_kctl_event *ev; if (snd_BUG_ON(!card || !id)) return; if (card->shutdown) return; guard(read_lock_irqsave)(&card->controls_rwlock); #if IS_ENABLED(CONFIG_SND_MIXER_OSS) card->mixer_oss_change_count++; #endif list_for_each_entry(ctl, &card->ctl_files, list) { if (!ctl->subscribed) continue; scoped_guard(spinlock, &ctl->read_lock) { list_for_each_entry(ev, &ctl->events, list) { if (ev->id.numid == id->numid) { ev->mask |= mask; goto _found; } } ev = kzalloc_obj(*ev, GFP_ATOMIC); if (ev) { ev->id = *id; ev->mask = mask; list_add_tail(&ev->list, &ctl->events); } else { dev_err(card->dev, "No memory available to allocate event\n"); } _found: wake_up(&ctl->change_sleep); } snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN); } } EXPORT_SYMBOL(snd_ctl_notify); /** * snd_ctl_notify_one - Send notification to user-space for a control change * @card: the card to send notification * @mask: the event mask, SNDRV_CTL_EVENT_* * @kctl: the pointer with the control instance * @ioff: the additional offset to the control index * * This function calls snd_ctl_notify() and does additional jobs * like LED state changes. */ void snd_ctl_notify_one(struct snd_card *card, unsigned int mask, struct snd_kcontrol *kctl, unsigned int ioff) { struct snd_ctl_elem_id id = kctl->id; struct snd_ctl_layer_ops *lops; id.index += ioff; id.numid += ioff; snd_ctl_notify(card, mask, &id); guard(rwsem_read)(&snd_ctl_layer_rwsem); for (lops = snd_ctl_layer; lops; lops = lops->next) lops->lnotify(card, mask, kctl, ioff); } EXPORT_SYMBOL(snd_ctl_notify_one); /** * snd_ctl_new - create a new control instance with some elements * @kctl: the pointer to store new control instance * @count: the number of elements in this control * @access: the default access flags for elements in this control * @file: given when locking these elements * * Allocates a memory object for a new control instance. The instance has * elements as many as the given number (@count). Each element has given * access permissions (@access). Each element is locked when @file is given. * * Return: 0 on success, error code on failure */ static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count, unsigned int access, struct snd_ctl_file *file) { unsigned int idx; if (count == 0 || count > MAX_CONTROL_COUNT) return -EINVAL; *kctl = kzalloc_flex(**kctl, vd, count); if (!*kctl) return -ENOMEM; (*kctl)->count = count; for (idx = 0; idx < count; idx++) { (*kctl)->vd[idx].access = access; (*kctl)->vd[idx].owner = file; } return 0; } /** * snd_ctl_new1 - create a control instance from the template * @ncontrol: the initialization record * @private_data: the private data to set * * Allocates a new struct snd_kcontrol instance and initialize from the given * template. When the access field of ncontrol is 0, it's assumed as * READWRITE access. When the count field is 0, it's assumes as one. * * Return: The pointer of the newly generated instance, or %NULL on failure. */ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol, void *private_data) { struct snd_kcontrol *kctl; unsigned int count; unsigned int access; int err; if (snd_BUG_ON(!ncontrol || !ncontrol->info)) return NULL; count = ncontrol->count; if (count == 0) count = 1; access = ncontrol->access; if (access == 0) access = SNDRV_CTL_ELEM_ACCESS_READWRITE; access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_VOLATILE | SNDRV_CTL_ELEM_ACCESS_INACTIVE | SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND | SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK | SNDRV_CTL_ELEM_ACCESS_LED_MASK | SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK); err = snd_ctl_new(&kctl, count, access, NULL); if (err < 0) return NULL; /* The 'numid' member is decided when calling snd_ctl_add(). */ kctl->id.iface = ncontrol->iface; kctl->id.device = ncontrol->device; kctl->id.subdevice = ncontrol->subdevice; if (ncontrol->name) { strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name)); if (strcmp(ncontrol->name, kctl->id.name) != 0) pr_warn("ALSA: Control name '%s' truncated to '%s'\n", ncontrol->name, kctl->id.name); } kctl->id.index = ncontrol->index; kctl->info = ncontrol->info; kctl->get = ncontrol->get; kctl->put = ncontrol->put; kctl->tlv.p = ncontrol->tlv.p; kctl->private_value = ncontrol->private_value; kctl->private_data = private_data; return kctl; } EXPORT_SYMBOL(snd_ctl_new1); /** * snd_ctl_free_one - release the control instance * @kcontrol: the control instance * * Releases the control instance created via snd_ctl_new() * or snd_ctl_new1(). * Don't call this after the control was added to the card. */ void snd_ctl_free_one(struct snd_kcontrol *kcontrol) { if (kcontrol) { if (kcontrol->private_free) kcontrol->private_free(kcontrol); kfree(kcontrol); } } EXPORT_SYMBOL(snd_ctl_free_one); static bool snd_ctl_remove_numid_conflict(struct snd_card *card, unsigned int count) { struct snd_kcontrol *kctl; /* Make sure that the ids assigned to the control do not wrap around */ if (card->last_numid >= UINT_MAX - count) card->last_numid = 0; list_for_each_entry(kctl, &card->controls, list) { if (kctl->id.numid < card->last_numid + 1 + count && kctl->id.numid + kctl->count > card->last_numid + 1) { card->last_numid = kctl->id.numid + kctl->count - 1; return true; } } return false; } static int snd_ctl_find_hole(struct snd_card *card, unsigned int count) { unsigned int iter = 100000; while (snd_ctl_remove_numid_conflict(card, count)) { if (--iter == 0) { /* this situation is very unlikely */ dev_err(card->dev, "unable to allocate new control numid\n"); return -ENOMEM; } } return 0; } /* check whether the given id is contained in the given kctl */ static bool elem_id_matches(const struct snd_kcontrol *kctl, const struct snd_ctl_elem_id *id) { return kctl->id.iface == id->iface && kctl->id.device == id->device && kctl->id.subdevice == id->subdevice && !strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) && kctl->id.index <= id->index && kctl->id.index + kctl->count > id->index; } #ifdef CONFIG_SND_CTL_FAST_LOOKUP /* Compute a hash key for the corresponding ctl id * It's for the name lookup, hence the numid is excluded. * The hash key is bound in LONG_MAX to be used for Xarray key. */ #define MULTIPLIER 37 static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id) { int i; unsigned long h; h = id->iface; h = MULTIPLIER * h + id->device; h = MULTIPLIER * h + id->subdevice; for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++) h = MULTIPLIER * h + id->name[i]; h = MULTIPLIER * h + id->index; h &= LONG_MAX; return h; } /* add hash entries to numid and ctl xarray tables */ static void add_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol) { struct snd_ctl_elem_id id = kcontrol->id; int i; xa_store_range(&card->ctl_numids, kcontrol->id.numid, kcontrol->id.numid + kcontrol->count - 1, kcontrol, GFP_KERNEL); for (i = 0; i < kcontrol->count; i++) { id.index = kcontrol->id.index + i; if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id), kcontrol, GFP_KERNEL)) { /* skip hash for this entry, noting we had collision */ card->ctl_hash_collision = true; dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n", id.iface, id.name, id.index); } } } /* remove hash entries that have been added */ static void remove_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol) { struct snd_ctl_elem_id id = kcontrol->id; struct snd_kcontrol *matched; unsigned long h; int i; for (i = 0; i < kcontrol->count; i++) { xa_erase(&card->ctl_numids, id.numid); h = get_ctl_id_hash(&id); matched = xa_load(&card->ctl_hash, h); if (matched && (matched == kcontrol || elem_id_matches(matched, &id))) xa_erase(&card->ctl_hash, h); id.index++; id.numid++; } } #else /* CONFIG_SND_CTL_FAST_LOOKUP */ static inline void add_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol) { } static inline void remove_hash_entries(struct snd_card *card, struct snd_kcontrol *kcontrol) { } #endif /* CONFIG_SND_CTL_FAST_LOOKUP */ enum snd_ctl_add_mode { CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE, }; /* add/replace a new kcontrol object; call with card->controls_rwsem locked */ static int __snd_ctl_add_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, enum snd_ctl_add_mode mode) { struct snd_ctl_elem_id id; unsigned int idx; struct snd_kcontrol *old; int err; lockdep_assert_held_write(&card->controls_rwsem); id = kcontrol->id; if (id.index > UINT_MAX - kcontrol->count) return -EINVAL; old = snd_ctl_find_id(card, &id); if (!old) { if (mode == CTL_REPLACE) return -EINVAL; } else { if (mode == CTL_ADD_EXCLUSIVE) { dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n", id.iface, id.device, id.subdevice, id.name, id.index); return -EBUSY; } err = snd_ctl_remove_locked(card, old); if (err < 0) return err; } if (snd_ctl_find_hole(card, kcontrol->count) < 0) return -ENOMEM; scoped_guard(write_lock_irq, &card->controls_rwlock) { list_add_tail(&kcontrol->list, &card->controls); card->controls_count += kcontrol->count; kcontrol->id.numid = card->last_numid + 1;