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c7cd7c748a
In sound_insert_unit(), the controlling structure 's' is allocated through kmalloc(). Then it is added to the sound driver list by invoking __sound_insert_unit(). Later on, if __register_chrdev() fails, 's' is removed from the list through __sound_remove_unit(). If 'index' is not less than 0, -EBUSY is returned to indicate the error. However, 's' is not deallocated on this execution path, leading to a memory leak bug. To fix the above issue, free 's' before -EBUSY is returned. Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
621 lines
14 KiB
C
621 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Sound core. This file is composed of two parts. sound_class
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* which is common to both OSS and ALSA and OSS sound core which
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* is used OSS or emulation of it.
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*/
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/*
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* First, the common part.
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/kdev_t.h>
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#include <linux/major.h>
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#include <sound/core.h>
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#ifdef CONFIG_SOUND_OSS_CORE
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static int __init init_oss_soundcore(void);
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static void cleanup_oss_soundcore(void);
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#else
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static inline int init_oss_soundcore(void) { return 0; }
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static inline void cleanup_oss_soundcore(void) { }
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#endif
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struct class *sound_class;
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EXPORT_SYMBOL(sound_class);
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MODULE_DESCRIPTION("Core sound module");
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MODULE_AUTHOR("Alan Cox");
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MODULE_LICENSE("GPL");
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static char *sound_devnode(struct device *dev, umode_t *mode)
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{
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if (MAJOR(dev->devt) == SOUND_MAJOR)
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return NULL;
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return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev));
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}
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static int __init init_soundcore(void)
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{
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int rc;
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rc = init_oss_soundcore();
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if (rc)
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return rc;
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sound_class = class_create(THIS_MODULE, "sound");
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if (IS_ERR(sound_class)) {
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cleanup_oss_soundcore();
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return PTR_ERR(sound_class);
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}
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sound_class->devnode = sound_devnode;
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return 0;
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}
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static void __exit cleanup_soundcore(void)
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{
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cleanup_oss_soundcore();
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class_destroy(sound_class);
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}
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subsys_initcall(init_soundcore);
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module_exit(cleanup_soundcore);
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#ifdef CONFIG_SOUND_OSS_CORE
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/*
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* OSS sound core handling. Breaks out sound functions to submodules
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*
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* Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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* Fixes:
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*
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* --------------------
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*
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* Top level handler for the sound subsystem. Various devices can
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* plug into this. The fact they don't all go via OSS doesn't mean
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* they don't have to implement the OSS API. There is a lot of logic
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* to keeping much of the OSS weight out of the code in a compatibility
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* module, but it's up to the driver to rember to load it...
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*
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* The code provides a set of functions for registration of devices
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* by type. This is done rather than providing a single call so that
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* we can hide any future changes in the internals (eg when we go to
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* 32bit dev_t) from the modules and their interface.
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*
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* Secondly we need to allocate the dsp, dsp16 and audio devices as
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* one. Thus we misuse the chains a bit to simplify this.
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*
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* Thirdly to make it more fun and for 2.3.x and above we do all
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* of this using fine grained locking.
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*
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* FIXME: we have to resolve modules and fine grained load/unload
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* locking at some point in 2.3.x.
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*/
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sound.h>
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#include <linux/kmod.h>
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#define SOUND_STEP 16
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struct sound_unit
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{
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int unit_minor;
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const struct file_operations *unit_fops;
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struct sound_unit *next;
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char name[32];
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};
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/*
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* By default, OSS sound_core claims full legacy minor range (0-255)
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* of SOUND_MAJOR to trap open attempts to any sound minor and
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* requests modules using custom sound-slot/service-* module aliases.
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* The only benefit of doing this is allowing use of custom module
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* aliases instead of the standard char-major-* ones. This behavior
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* prevents alternative OSS implementation and is scheduled to be
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* removed.
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*
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* CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel
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* parameter are added to allow distros and developers to try and
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* switch to alternative implementations without needing to rebuild
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* the kernel in the meantime. If preclaim_oss is non-zero, the
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* kernel will behave the same as before. All SOUND_MAJOR minors are
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* preclaimed and the custom module aliases along with standard chrdev
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* ones are emitted if a missing device is opened. If preclaim_oss is
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* zero, sound_core only grabs what's actually in use and for missing
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* devices only the standard chrdev aliases are requested.
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*
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* All these clutters are scheduled to be removed along with
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* sound-slot/service-* module aliases.
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*/
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#ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM
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static int preclaim_oss = 1;
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#else
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static int preclaim_oss = 0;
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#endif
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module_param(preclaim_oss, int, 0444);
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static int soundcore_open(struct inode *, struct file *);
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static const struct file_operations soundcore_fops =
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{
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/* We must have an owner or the module locking fails */
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.owner = THIS_MODULE,
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.open = soundcore_open,
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.llseek = noop_llseek,
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};
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/*
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* Low level list operator. Scan the ordered list, find a hole and
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* join into it. Called with the lock asserted
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*/
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static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top)
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{
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int n=low;
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if (index < 0) { /* first free */
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while (*list && (*list)->unit_minor<n)
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list=&((*list)->next);
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while(n<top)
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{
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/* Found a hole ? */
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if(*list==NULL || (*list)->unit_minor>n)
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break;
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list=&((*list)->next);
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n+=SOUND_STEP;
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}
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if(n>=top)
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return -ENOENT;
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} else {
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n = low+(index*16);
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while (*list) {
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if ((*list)->unit_minor==n)
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return -EBUSY;
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if ((*list)->unit_minor>n)
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break;
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list=&((*list)->next);
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}
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}
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/*
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* Fill it in
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*/
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s->unit_minor=n;
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s->unit_fops=fops;
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/*
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* Link it
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*/
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s->next=*list;
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*list=s;
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return n;
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}
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/*
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* Remove a node from the chain. Called with the lock asserted
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*/
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static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit)
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{
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while(*list)
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{
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struct sound_unit *p=*list;
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if(p->unit_minor==unit)
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{
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*list=p->next;
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return p;
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}
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list=&(p->next);
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}
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printk(KERN_ERR "Sound device %d went missing!\n", unit);
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return NULL;
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}
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/*
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* This lock guards the sound loader list.
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*/
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static DEFINE_SPINLOCK(sound_loader_lock);
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/*
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* Allocate the controlling structure and add it to the sound driver
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* list. Acquires locks as needed
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*/
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static int sound_insert_unit(struct sound_unit **list, const struct file_operations *fops, int index, int low, int top, const char *name, umode_t mode, struct device *dev)
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{
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struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL);
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int r;
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if (!s)
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return -ENOMEM;
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spin_lock(&sound_loader_lock);
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retry:
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r = __sound_insert_unit(s, list, fops, index, low, top);
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spin_unlock(&sound_loader_lock);
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if (r < 0)
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goto fail;
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else if (r < SOUND_STEP)
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sprintf(s->name, "sound/%s", name);
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else
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sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP);
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if (!preclaim_oss) {
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/*
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* Something else might have grabbed the minor. If
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* first free slot is requested, rescan with @low set
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* to the next unit; otherwise, -EBUSY.
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*/
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r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name,
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&soundcore_fops);
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if (r < 0) {
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spin_lock(&sound_loader_lock);
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__sound_remove_unit(list, s->unit_minor);
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if (index < 0) {
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low = s->unit_minor + SOUND_STEP;
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goto retry;
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}
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spin_unlock(&sound_loader_lock);
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r = -EBUSY;
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goto fail;
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}
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}
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device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
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NULL, "%s", s->name+6);
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return s->unit_minor;
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fail:
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kfree(s);
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return r;
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}
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/*
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* Remove a unit. Acquires locks as needed. The drivers MUST have
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* completed the removal before their file operations become
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* invalid.
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*/
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static void sound_remove_unit(struct sound_unit **list, int unit)
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{
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struct sound_unit *p;
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spin_lock(&sound_loader_lock);
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p = __sound_remove_unit(list, unit);
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spin_unlock(&sound_loader_lock);
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if (p) {
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if (!preclaim_oss)
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__unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1,
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p->name);
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device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor));
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kfree(p);
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}
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}
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/*
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* Allocations
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*
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* 0 *16 Mixers
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* 1 *8 Sequencers
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* 2 *16 Midi
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* 3 *16 DSP
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* 4 *16 SunDSP
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* 5 *16 DSP16
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* 6 -- sndstat (obsolete)
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* 7 *16 unused
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* 8 -- alternate sequencer (see above)
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* 9 *16 raw synthesizer access
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* 10 *16 unused
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* 11 *16 unused
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* 12 *16 unused
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* 13 *16 unused
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* 14 *16 unused
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* 15 *16 unused
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*/
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static struct sound_unit *chains[SOUND_STEP];
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/**
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* register_sound_special_device - register a special sound node
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* @fops: File operations for the driver
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* @unit: Unit number to allocate
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* @dev: device pointer
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*
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* Allocate a special sound device by minor number from the sound
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* subsystem.
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*
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* Return: The allocated number is returned on success. On failure,
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* a negative error code is returned.
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*/
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int register_sound_special_device(const struct file_operations *fops, int unit,
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struct device *dev)
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{
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const int chain = unit % SOUND_STEP;
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int max_unit = 256;
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const char *name;
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char _name[16];
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switch (chain) {
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case 0:
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name = "mixer";
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break;
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case 1:
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name = "sequencer";
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if (unit >= SOUND_STEP)
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goto __unknown;
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max_unit = unit + 1;
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break;
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case 2:
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name = "midi";
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break;
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case 3:
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name = "dsp";
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break;
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case 4:
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name = "audio";
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break;
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case 5:
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name = "dspW";
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break;
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case 8:
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name = "sequencer2";
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if (unit >= SOUND_STEP)
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goto __unknown;
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max_unit = unit + 1;
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break;
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case 9:
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name = "dmmidi";
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break;
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case 10:
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name = "dmfm";
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break;
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case 12:
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name = "adsp";
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break;
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case 13:
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name = "amidi";
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break;
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case 14:
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name = "admmidi";
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break;
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default:
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{
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__unknown:
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sprintf(_name, "unknown%d", chain);
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if (unit >= SOUND_STEP)
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strcat(_name, "-");
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name = _name;
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}
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break;
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}
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return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit,
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name, 0600, dev);
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}
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EXPORT_SYMBOL(register_sound_special_device);
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int register_sound_special(const struct file_operations *fops, int unit)
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{
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return register_sound_special_device(fops, unit, NULL);
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}
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EXPORT_SYMBOL(register_sound_special);
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/**
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* register_sound_mixer - register a mixer device
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* @fops: File operations for the driver
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* @dev: Unit number to allocate
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*
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* Allocate a mixer device. Unit is the number of the mixer requested.
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* Pass -1 to request the next free mixer unit.
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*
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* Return: On success, the allocated number is returned. On failure,
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* a negative error code is returned.
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*/
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int register_sound_mixer(const struct file_operations *fops, int dev)
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{
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return sound_insert_unit(&chains[0], fops, dev, 0, 128,
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"mixer", 0600, NULL);
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}
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EXPORT_SYMBOL(register_sound_mixer);
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/*
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* DSP's are registered as a triple. Register only one and cheat
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* in open - see below.
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*/
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/**
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* register_sound_dsp - register a DSP device
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* @fops: File operations for the driver
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* @dev: Unit number to allocate
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*
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* Allocate a DSP device. Unit is the number of the DSP requested.
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* Pass -1 to request the next free DSP unit.
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*
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* This function allocates both the audio and dsp device entries together
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* and will always allocate them as a matching pair - eg dsp3/audio3
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*
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* Return: On success, the allocated number is returned. On failure,
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* a negative error code is returned.
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*/
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int register_sound_dsp(const struct file_operations *fops, int dev)
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{
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return sound_insert_unit(&chains[3], fops, dev, 3, 131,
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"dsp", 0600, NULL);
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}
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EXPORT_SYMBOL(register_sound_dsp);
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/**
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* unregister_sound_special - unregister a special sound device
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* @unit: unit number to allocate
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*
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* Release a sound device that was allocated with
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* register_sound_special(). The unit passed is the return value from
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* the register function.
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*/
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|
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void unregister_sound_special(int unit)
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{
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sound_remove_unit(&chains[unit % SOUND_STEP], unit);
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}
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EXPORT_SYMBOL(unregister_sound_special);
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|
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/**
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* unregister_sound_mixer - unregister a mixer
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* @unit: unit number to allocate
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*
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* Release a sound device that was allocated with register_sound_mixer().
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* The unit passed is the return value from the register function.
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*/
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void unregister_sound_mixer(int unit)
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{
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sound_remove_unit(&chains[0], unit);
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}
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EXPORT_SYMBOL(unregister_sound_mixer);
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|
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/**
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* unregister_sound_dsp - unregister a DSP device
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* @unit: unit number to allocate
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*
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* Release a sound device that was allocated with register_sound_dsp().
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* The unit passed is the return value from the register function.
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*
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* Both of the allocated units are released together automatically.
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*/
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void unregister_sound_dsp(int unit)
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{
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sound_remove_unit(&chains[3], unit);
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}
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|
|
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EXPORT_SYMBOL(unregister_sound_dsp);
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|
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static struct sound_unit *__look_for_unit(int chain, int unit)
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{
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struct sound_unit *s;
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s=chains[chain];
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while(s && s->unit_minor <= unit)
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{
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if(s->unit_minor==unit)
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return s;
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s=s->next;
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}
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return NULL;
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}
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|
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static int soundcore_open(struct inode *inode, struct file *file)
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{
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int chain;
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int unit = iminor(inode);
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struct sound_unit *s;
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const struct file_operations *new_fops = NULL;
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chain=unit&0x0F;
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if(chain==4 || chain==5) /* dsp/audio/dsp16 */
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{
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unit&=0xF0;
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unit|=3;
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chain=3;
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}
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|
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spin_lock(&sound_loader_lock);
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s = __look_for_unit(chain, unit);
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if (s)
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new_fops = fops_get(s->unit_fops);
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if (preclaim_oss && !new_fops) {
|
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spin_unlock(&sound_loader_lock);
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|
|
/*
|
|
* Please, don't change this order or code.
|
|
* For ALSA slot means soundcard and OSS emulation code
|
|
* comes as add-on modules which aren't depend on
|
|
* ALSA toplevel modules for soundcards, thus we need
|
|
* load them at first. [Jaroslav Kysela <perex@jcu.cz>]
|
|
*/
|
|
request_module("sound-slot-%i", unit>>4);
|
|
request_module("sound-service-%i-%i", unit>>4, chain);
|
|
|
|
/*
|
|
* sound-slot/service-* module aliases are scheduled
|
|
* for removal in favor of the standard char-major-*
|
|
* module aliases. For the time being, generate both
|
|
* the legacy and standard module aliases to ease
|
|
* transition.
|
|
*/
|
|
if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0)
|
|
request_module("char-major-%d", SOUND_MAJOR);
|
|
|
|
spin_lock(&sound_loader_lock);
|
|
s = __look_for_unit(chain, unit);
|
|
if (s)
|
|
new_fops = fops_get(s->unit_fops);
|
|
}
|
|
spin_unlock(&sound_loader_lock);
|
|
if (new_fops) {
|
|
/*
|
|
* We rely upon the fact that we can't be unloaded while the
|
|
* subdriver is there.
|
|
*/
|
|
int err = 0;
|
|
replace_fops(file, new_fops);
|
|
|
|
if (file->f_op->open)
|
|
err = file->f_op->open(inode,file);
|
|
|
|
return err;
|
|
}
|
|
return -ENODEV;
|
|
}
|
|
|
|
MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
|
|
|
|
static void cleanup_oss_soundcore(void)
|
|
{
|
|
/* We have nothing to really do here - we know the lists must be
|
|
empty */
|
|
unregister_chrdev(SOUND_MAJOR, "sound");
|
|
}
|
|
|
|
static int __init init_oss_soundcore(void)
|
|
{
|
|
if (preclaim_oss &&
|
|
register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) {
|
|
printk(KERN_ERR "soundcore: sound device already in use.\n");
|
|
return -EBUSY;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_SOUND_OSS_CORE */
|