string: factorize skip_spaces and export it to be generally available
[safe/jmp/linux-2.6] / sound / core / control.c
index 31ad581..268ab74 100644 (file)
@@ -1,6 +1,6 @@
 /*
  *  Routines for driver control interface
- *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
  *
  *
  *   This program is free software; you can redistribute it and/or modify
  *
  */
 
-#include <sound/driver.h>
 #include <linux/threads.h>
 #include <linux/interrupt.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/time.h>
@@ -75,7 +73,9 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
        init_waitqueue_head(&ctl->change_sleep);
        spin_lock_init(&ctl->read_lock);
        ctl->card = card;
-       ctl->pid = current->pid;
+       ctl->prefer_pcm_subdevice = -1;
+       ctl->prefer_rawmidi_subdevice = -1;
+       ctl->pid = get_pid(task_pid(current));
        file->private_data = ctl;
        write_lock_irqsave(&card->ctl_files_rwlock, flags);
        list_add_tail(&ctl->list, &card->ctl_files);
@@ -92,42 +92,40 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
 
 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 {
+       unsigned long flags;
        struct snd_kctl_event *cread;
        
-       spin_lock(&ctl->read_lock);
+       spin_lock_irqsave(&ctl->read_lock, flags);
        while (!list_empty(&ctl->events)) {
                cread = snd_kctl_event(ctl->events.next);
                list_del(&cread->list);
                kfree(cread);
        }
-       spin_unlock(&ctl->read_lock);
+       spin_unlock_irqrestore(&ctl->read_lock, flags);
 }
 
 static int snd_ctl_release(struct inode *inode, struct file *file)
 {
        unsigned long flags;
-       struct list_head *list;
        struct snd_card *card;
        struct snd_ctl_file *ctl;
        struct snd_kcontrol *control;
        unsigned int idx;
 
        ctl = file->private_data;
-       fasync_helper(-1, file, 0, &ctl->fasync);
        file->private_data = NULL;
        card = ctl->card;
        write_lock_irqsave(&card->ctl_files_rwlock, flags);
        list_del(&ctl->list);
        write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
        down_write(&card->controls_rwsem);
-       list_for_each(list, &card->controls) {
-               control = snd_kcontrol(list);
+       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;
-       }
        up_write(&card->controls_rwsem);
        snd_ctl_empty_read_queue(ctl);
+       put_pid(ctl->pid);
        kfree(ctl);
        module_put(card->module);
        snd_card_file_remove(card, file);
@@ -138,23 +136,20 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask,
                    struct snd_ctl_elem_id *id)
 {
        unsigned long flags;
-       struct list_head *flist;
        struct snd_ctl_file *ctl;
        struct snd_kctl_event *ev;
        
-       snd_assert(card != NULL && id != NULL, return);
+       if (snd_BUG_ON(!card || !id))
+               return;
        read_lock(&card->ctl_files_rwlock);
 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
        card->mixer_oss_change_count++;
 #endif
-       list_for_each(flist, &card->ctl_files) {
-               struct list_head *elist;
-               ctl = snd_ctl_file(flist);
+       list_for_each_entry(ctl, &card->ctl_files, list) {
                if (!ctl->subscribed)
                        continue;
                spin_lock_irqsave(&ctl->read_lock, flags);
-               list_for_each(elist, &ctl->events) {
-                       ev = snd_kctl_event(elist);
+               list_for_each_entry(ev, &ctl->events, list) {
                        if (ev->id.numid == id->numid) {
                                ev->mask |= mask;
                                goto _found;
@@ -188,13 +183,14 @@ EXPORT_SYMBOL(snd_ctl_notify);
  *
  * Returns the pointer of the new instance, or NULL on failure.
  */
-struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, unsigned int access)
+static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
+                                       unsigned int access)
 {
        struct snd_kcontrol *kctl;
        unsigned int idx;
        
-       snd_assert(control != NULL, return NULL);
-       snd_assert(control->count > 0, return NULL);
+       if (snd_BUG_ON(!control || !control->count))
+               return NULL;
        kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
        if (kctl == NULL) {
                snd_printk(KERN_ERR "Cannot allocate control instance\n");
@@ -206,8 +202,6 @@ struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, unsigned int acce
        return kctl;
 }
 
-EXPORT_SYMBOL(snd_ctl_new);
-
 /**
  * snd_ctl_new1 - create a control instance from the template
  * @ncontrol: the initialization record
@@ -225,21 +219,24 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
        struct snd_kcontrol kctl;
        unsigned int access;
        
-       snd_assert(ncontrol != NULL, return NULL);
-       snd_assert(ncontrol->info != NULL, return NULL);
+       if (snd_BUG_ON(!ncontrol || !ncontrol->info))
+               return NULL;
        memset(&kctl, 0, sizeof(kctl));
        kctl.id.iface = ncontrol->iface;
        kctl.id.device = ncontrol->device;
        kctl.id.subdevice = ncontrol->subdevice;
-       if (ncontrol->name)
+       if (ncontrol->name) {
                strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
+               if (strcmp(ncontrol->name, kctl.id.name) != 0)
+                       snd_printk(KERN_WARNING
+                                  "Control name '%s' truncated to '%s'\n",
+                                  ncontrol->name, kctl.id.name);
+       }
        kctl.id.index = ncontrol->index;
        kctl.count = ncontrol->count ? ncontrol->count : 1;
        access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
                 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
                                      SNDRV_CTL_ELEM_ACCESS_INACTIVE|
-                                     SNDRV_CTL_ELEM_ACCESS_DINDIRECT|
-                                     SNDRV_CTL_ELEM_ACCESS_INDIRECT|
                                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
                                      SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
        kctl.info = ncontrol->info;
@@ -275,11 +272,9 @@ EXPORT_SYMBOL(snd_ctl_free_one);
 static unsigned int snd_ctl_hole_check(struct snd_card *card,
                                       unsigned int count)
 {
-       struct list_head *list;
        struct snd_kcontrol *kctl;
 
-       list_for_each(list, &card->controls) {
-               kctl = snd_kcontrol(list);
+       list_for_each_entry(kctl, &card->controls, list) {
                if ((kctl->id.numid <= card->last_numid &&
                     kctl->id.numid + kctl->count > card->last_numid) ||
                    (kctl->id.numid <= card->last_numid + count - 1 &&
@@ -326,8 +321,8 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 
        if (! kcontrol)
                return err;
-       snd_assert(card != NULL, goto error);
-       snd_assert(kcontrol->info != NULL, goto error);
+       if (snd_BUG_ON(!card || !kcontrol->info))
+               goto error;
        id = kcontrol->id;
        down_write(&card->controls_rwsem);
        if (snd_ctl_find_id(card, &id)) {
@@ -378,7 +373,8 @@ int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
        struct snd_ctl_elem_id id;
        unsigned int idx;
 
-       snd_assert(card != NULL && kcontrol != NULL, return -EINVAL);
+       if (snd_BUG_ON(!card || !kcontrol))
+               return -EINVAL;
        list_del(&kcontrol->list);
        card->controls_count -= kcontrol->count;
        id = kcontrol->id;
@@ -419,7 +415,7 @@ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 EXPORT_SYMBOL(snd_ctl_remove_id);
 
 /**
- * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
+ * snd_ctl_remove_user_ctl - remove and release the unlocked user control
  * @file: active control handle
  * @id: the control id to remove
  *
@@ -428,8 +424,8 @@ EXPORT_SYMBOL(snd_ctl_remove_id);
  * 
  * Returns 0 if successful, or a negative error code on failure.
  */
-static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
-                                     struct snd_ctl_elem_id *id)
+static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
+                                  struct snd_ctl_elem_id *id)
 {
        struct snd_card *card = file->card;
        struct snd_kcontrol *kctl;
@@ -438,15 +434,23 @@ static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
        down_write(&card->controls_rwsem);
        kctl = snd_ctl_find_id(card, id);
        if (kctl == NULL) {
-               up_write(&card->controls_rwsem);
-               return -ENOENT;
+               ret = -ENOENT;
+               goto error;
+       }
+       if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
+               ret = -EINVAL;
+               goto error;
        }
        for (idx = 0; idx < kctl->count; idx++)
                if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
-                       up_write(&card->controls_rwsem);
-                       return -EBUSY;
+                       ret = -EBUSY;
+                       goto error;
                }
        ret = snd_ctl_remove(card, kctl);
+       if (ret < 0)
+               goto error;
+       card->user_ctl_count--;
+error:
        up_write(&card->controls_rwsem);
        return ret;
 }
@@ -496,12 +500,11 @@ EXPORT_SYMBOL(snd_ctl_rename_id);
  */
 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 {
-       struct list_head *list;
        struct snd_kcontrol *kctl;
 
-       snd_assert(card != NULL && numid != 0, return NULL);
-       list_for_each(list, &card->controls) {
-               kctl = snd_kcontrol(list);
+       if (snd_BUG_ON(!card || !numid))
+               return NULL;
+       list_for_each_entry(kctl, &card->controls, list) {
                if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
                        return kctl;
        }
@@ -525,14 +528,13 @@ EXPORT_SYMBOL(snd_ctl_find_numid);
 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
                                     struct snd_ctl_elem_id *id)
 {
-       struct list_head *list;
        struct snd_kcontrol *kctl;
 
-       snd_assert(card != NULL && id != NULL, return NULL);
+       if (snd_BUG_ON(!card || !id))
+               return NULL;
        if (id->numid != 0)
                return snd_ctl_find_numid(card, id->numid);
-       list_for_each(list, &card->controls) {
-               kctl = snd_kcontrol(list);
+       list_for_each_entry(kctl, &card->controls, list) {
                if (kctl->id.iface != id->iface)
                        continue;
                if (kctl->id.device != id->device)
@@ -662,7 +664,7 @@ static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 #endif
        result = kctl->info(kctl, info);
        if (result >= 0) {
-               snd_assert(info->access == 0, );
+               snd_BUG_ON(info->access);
                index_offset = snd_ctl_get_ioff(kctl, &info->id);
                vd = &kctl->vd[index_offset];
                snd_ctl_build_ioff(&info->id, kctl, index_offset);
@@ -671,7 +673,7 @@ static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
                        info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
                        if (vd->owner == ctl)
                                info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
-                       info->owner = vd->owner_pid;
+                       info->owner = pid_vnr(vd->owner->pid);
                } else {
                        info->owner = -1;
                }
@@ -699,12 +701,13 @@ static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
        return result;
 }
 
-int snd_ctl_elem_read(struct snd_card *card, struct snd_ctl_elem_value *control)
+static int snd_ctl_elem_read(struct snd_card *card,
+                            struct snd_ctl_elem_value *control)
 {
        struct snd_kcontrol *kctl;
        struct snd_kcontrol_volatile *vd;
        unsigned int index_offset;
-       int result, indirect;
+       int result;
 
        down_read(&card->controls_rwsem);
        kctl = snd_ctl_find_id(card, &control->id);
@@ -713,37 +716,27 @@ int snd_ctl_elem_read(struct snd_card *card, struct snd_ctl_elem_value *control)
        } else {
                index_offset = snd_ctl_get_ioff(kctl, &control->id);
                vd = &kctl->vd[index_offset];
-               indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
-               if (control->indirect != indirect) {
-                       result = -EACCES;
-               } else {
-                       if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get != NULL) {
-                               snd_ctl_build_ioff(&control->id, kctl, index_offset);
-                               result = kctl->get(kctl, control);
-                       } else {
-                               result = -EPERM;
-                       }
-               }
+               if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
+                   kctl->get != NULL) {
+                       snd_ctl_build_ioff(&control->id, kctl, index_offset);
+                       result = kctl->get(kctl, control);
+               } else
+                       result = -EPERM;
        }
        up_read(&card->controls_rwsem);
        return result;
 }
 
-EXPORT_SYMBOL(snd_ctl_elem_read);
-
 static int snd_ctl_elem_read_user(struct snd_card *card,
                                  struct snd_ctl_elem_value __user *_control)
 {
        struct snd_ctl_elem_value *control;
        int result;
-       
-       control = kmalloc(sizeof(*control), GFP_KERNEL);
-       if (control == NULL)
-               return -ENOMEM; 
-       if (copy_from_user(control, _control, sizeof(*control))) {
-               kfree(control);
-               return -EFAULT;
-       }
+
+       control = memdup_user(_control, sizeof(*control));
+       if (IS_ERR(control))
+               return PTR_ERR(control);
+
        snd_power_lock(card);
        result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
        if (result >= 0)
@@ -756,13 +749,13 @@ static int snd_ctl_elem_read_user(struct snd_card *card,
        return result;
 }
 
-int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
-                      struct snd_ctl_elem_value *control)
+static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
+                             struct snd_ctl_elem_value *control)
 {
        struct snd_kcontrol *kctl;
        struct snd_kcontrol_volatile *vd;
        unsigned int index_offset;
-       int result, indirect;
+       int result;
 
        down_read(&card->controls_rwsem);
        kctl = snd_ctl_find_id(card, &control->id);
@@ -771,31 +764,25 @@ int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
        } else {
                index_offset = snd_ctl_get_ioff(kctl, &control->id);
                vd = &kctl->vd[index_offset];
-               indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
-               if (control->indirect != indirect) {
-                       result = -EACCES;
+               if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
+                   kctl->put == NULL ||
+                   (file && vd->owner && vd->owner != file)) {
+                       result = -EPERM;
                } else {
-                       if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
-                           kctl->put == NULL ||
-                           (file && vd->owner != NULL && vd->owner != file)) {
-                               result = -EPERM;
-                       } else {
-                               snd_ctl_build_ioff(&control->id, kctl, index_offset);
-                               result = kctl->put(kctl, control);
-                       }
-                       if (result > 0) {
-                               up_read(&card->controls_rwsem);
-                               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &control->id);
-                               return 0;
-                       }
+                       snd_ctl_build_ioff(&control->id, kctl, index_offset);
+                       result = kctl->put(kctl, control);
+               }
+               if (result > 0) {
+                       up_read(&card->controls_rwsem);
+                       snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+                                      &control->id);
+                       return 0;
                }
        }
        up_read(&card->controls_rwsem);
        return result;
 }
 
-EXPORT_SYMBOL(snd_ctl_elem_write);
-
 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
                                   struct snd_ctl_elem_value __user *_control)
 {
@@ -803,13 +790,10 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
        struct snd_card *card;
        int result;
 
-       control = kmalloc(sizeof(*control), GFP_KERNEL);
-       if (control == NULL)
-               return -ENOMEM; 
-       if (copy_from_user(control, _control, sizeof(*control))) {
-               kfree(control);
-               return -EFAULT;
-       }
+       control = memdup_user(_control, sizeof(*control));
+       if (IS_ERR(control))
+               return PTR_ERR(control);
+
        card = file->card;
        snd_power_lock(card);
        result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
@@ -844,7 +828,6 @@ static int snd_ctl_elem_lock(struct snd_ctl_file *file,
                        result = -EBUSY;
                else {
                        vd->owner = file;
-                       vd->owner_pid = current->pid;
                        result = 0;
                }
        }
@@ -875,7 +858,6 @@ static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
                        result = -EPERM;
                else {
                        vd->owner = NULL;
-                       vd->owner_pid = 0;
                        result = 0;
                }
        }
@@ -935,13 +917,10 @@ static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
        if (op_flag > 0) {
                if (size > 1024 * 128)  /* sane value */
                        return -EINVAL;
-               new_data = kmalloc(size, GFP_KERNEL);
-               if (new_data == NULL)
-                       return -ENOMEM;
-               if (copy_from_user(new_data, tlv, size)) {
-                       kfree(new_data);
-                       return -EFAULT;
-               }
+
+               new_data = memdup_user(tlv, size);
+               if (IS_ERR(new_data))
+                       return PTR_ERR(new_data);
                change = ue->tlv_data_size != size;
                if (!change)
                        change = memcmp(ue->tlv_data, new_data, size);
@@ -949,6 +928,8 @@ static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
                ue->tlv_data = new_data;
                ue->tlv_data_size = size;
        } else {
+               if (! ue->tlv_data_size || ! ue->tlv_data)
+                       return -ENXIO;
                if (size < ue->tlv_data_size)
                        return -ENOSPC;
                if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
@@ -977,7 +958,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
        
        if (card->user_ctl_count >= MAX_USER_CONTROLS)
                return -ENOMEM;
-       if (info->count > 1024)
+       if (info->count < 1)
                return -EINVAL;
        access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
                (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
@@ -1014,10 +995,6 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
        }
        switch (info->type) {
        case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
-               private_size = sizeof(char);
-               if (info->count > 128)
-                       return -EINVAL;
-               break;
        case SNDRV_CTL_ELEM_TYPE_INTEGER:
                private_size = sizeof(long);
                if (info->count > 128)
@@ -1046,6 +1023,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
        if (ue == NULL)
                return -ENOMEM;
        ue->info = *info;
+       ue->info.access = 0;
        ue->elem_data = (char *)ue + sizeof(*ue);
        ue->elem_data_size = private_size;
        kctl.private_free = snd_ctl_elem_user_free;
@@ -1081,18 +1059,10 @@ static int snd_ctl_elem_remove(struct snd_ctl_file *file,
                               struct snd_ctl_elem_id __user *_id)
 {
        struct snd_ctl_elem_id id;
-       int err;
 
        if (copy_from_user(&id, _id, sizeof(id)))
                return -EFAULT;
-       err = snd_ctl_remove_unlocked_id(file, &id);
-       if (! err) {
-               struct snd_card *card = file->card;
-               down_write(&card->controls_rwsem);
-               card->user_ctl_count--;
-               up_write(&card->controls_rwsem);
-       }
-       return err;
+       return snd_ctl_remove_user_ctl(file, &id);
 }
 
 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
@@ -1149,7 +1119,7 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
                goto __kctl_end;
        }
        if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
-               if (file && vd->owner != NULL && vd->owner != file) {
+               if (vd->owner != NULL && vd->owner != file) {
                        err = -EPERM;
                        goto __kctl_end;
                }
@@ -1181,7 +1151,6 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 {
        struct snd_ctl_file *ctl;
        struct snd_card *card;
-       struct list_head *list;
        struct snd_kctl_ioctl *p;
        void __user *argp = (void __user *)arg;
        int __user *ip = argp;
@@ -1189,7 +1158,8 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 
        ctl = file->private_data;
        card = ctl->card;
-       snd_assert(card != NULL, return -ENXIO);
+       if (snd_BUG_ON(!card))
+               return -ENXIO;
        switch (cmd) {
        case SNDRV_CTL_IOCTL_PVERSION:
                return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
@@ -1231,8 +1201,7 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 #endif
        }
        down_read(&snd_ioctl_rwsem);
-       list_for_each(list, &snd_control_ioctls) {
-               p = list_entry(list, struct snd_kctl_ioctl, list);
+       list_for_each_entry(p, &snd_control_ioctls, list) {
                err = p->fioctl(card, ctl, cmd, arg);
                if (err != -ENOIOCTLCMD) {
                        up_read(&snd_ioctl_rwsem);
@@ -1252,7 +1221,8 @@ static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
        ssize_t result = 0;
 
        ctl = file->private_data;
-       snd_assert(ctl != NULL && ctl->card != NULL, return -ENXIO);
+       if (snd_BUG_ON(!ctl || !ctl->card))
+               return -ENXIO;
        if (!ctl->subscribed)
                return -EBADFD;
        if (count < sizeof(struct snd_ctl_event))
@@ -1274,7 +1244,7 @@ static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
                        schedule();
                        remove_wait_queue(&ctl->change_sleep, &wait);
                        if (signal_pending(current))
-                               return result > 0 ? result : -ERESTARTSYS;
+                               return -ERESTARTSYS;
                        spin_lock_irq(&ctl->read_lock);
                }
                kev = snd_kctl_event(ctl->events.next);
@@ -1356,13 +1326,12 @@ EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
                                     struct list_head *lists)
 {
-       struct list_head *list;
        struct snd_kctl_ioctl *p;
 
-       snd_assert(fcn != NULL, return -EINVAL);
+       if (snd_BUG_ON(!fcn))
+               return -EINVAL;
        down_write(&snd_ioctl_rwsem);
-       list_for_each(list, lists) {
-               p = list_entry(list, struct snd_kctl_ioctl, list);
+       list_for_each_entry(p, lists, list) {
                if (p->fioctl == fcn) {
                        list_del(&p->list);
                        up_write(&snd_ioctl_rwsem);
@@ -1394,12 +1363,9 @@ EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
 static int snd_ctl_fasync(int fd, struct file * file, int on)
 {
        struct snd_ctl_file *ctl;
-       int err;
+
        ctl = file->private_data;
-       err = fasync_helper(fd, file, on, &ctl->fasync);
-       if (err < 0)
-               return err;
-       return 0;
+       return fasync_helper(fd, file, on, &ctl->fasync);
 }
 
 /*
@@ -1415,7 +1381,7 @@ static int snd_ctl_fasync(int fd, struct file * file, int on)
  *  INIT PART
  */
 
-static struct file_operations snd_ctl_f_ops =
+static const struct file_operations snd_ctl_f_ops =
 {
        .owner =        THIS_MODULE,
        .read =         snd_ctl_read,
@@ -1436,9 +1402,11 @@ static int snd_ctl_dev_register(struct snd_device *device)
        int err, cardnum;
        char name[16];
 
-       snd_assert(card != NULL, return -ENXIO);
+       if (snd_BUG_ON(!card))
+               return -ENXIO;
        cardnum = card->number;
-       snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
+       if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
+               return -ENXIO;
        sprintf(name, "controlC%i", cardnum);
        if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
                                       &snd_ctl_f_ops, card, name)) < 0)
@@ -1452,21 +1420,21 @@ static int snd_ctl_dev_register(struct snd_device *device)
 static int snd_ctl_dev_disconnect(struct snd_device *device)
 {
        struct snd_card *card = device->device_data;
-       struct list_head *flist;
        struct snd_ctl_file *ctl;
        int err, cardnum;
 
-       snd_assert(card != NULL, return -ENXIO);
+       if (snd_BUG_ON(!card))
+               return -ENXIO;
        cardnum = card->number;
-       snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
+       if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
+               return -ENXIO;
 
-       down_read(&card->controls_rwsem);
-       list_for_each(flist, &card->ctl_files) {
-               ctl = snd_ctl_file(flist);
+       read_lock(&card->ctl_files_rwlock);
+       list_for_each_entry(ctl, &card->ctl_files, list) {
                wake_up(&ctl->change_sleep);
                kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
        }
-       up_read(&card->controls_rwsem);
+       read_unlock(&card->ctl_files_rwlock);
 
        if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
                                         card, -1)) < 0)
@@ -1503,6 +1471,34 @@ int snd_ctl_create(struct snd_card *card)
                .dev_disconnect = snd_ctl_dev_disconnect,
        };
 
-       snd_assert(card != NULL, return -ENXIO);
+       if (snd_BUG_ON(!card))
+               return -ENXIO;
        return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
 }
+
+/*
+ * Frequently used control callbacks
+ */
+int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
+                             struct snd_ctl_elem_info *uinfo)
+{
+       uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+       uinfo->count = 1;
+       uinfo->value.integer.min = 0;
+       uinfo->value.integer.max = 1;
+       return 0;
+}
+
+EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
+
+int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
+                               struct snd_ctl_elem_info *uinfo)
+{
+       uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+       uinfo->count = 2;
+       uinfo->value.integer.min = 0;
+       uinfo->value.integer.max = 1;
+       return 0;
+}
+
+EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);