To support userspace audio daemons like Virtual OSS, /dev/sndstat is

made writeable by the root user. Userspace audio daemons can add or
update an entry in /dev/sndstat by doing a single system write call to
any /dev/sndstat file descriptor handle. When the audio daemon closes the
file handle or is killed the entry disappears.

While at it, cleanup the sound status code a bit:
- keep the device list sorted to avoid sorting the list every time a
  /dev/sndstat read request is made.
- factor out locking into a pair of locking macros.
- use the sound status lock to protect all per file handle states,
  when generating the output for /dev/sndstat and when removing or
  adding sound status devices. This way sndstat_acquire() and
  sndstat_release() become superfluous and can be removed.

Reviewed by:		mav @
Differential Revision:	https://reviews.freebsd.org/D5191

1 files changed, 0 insertions, 2 deletions

diff --git a/sys/dev/sound/pcm/sound.h b/sys/dev/sound/pcm/sound.h
index 32e034330f74..2897aed18508 100644
--- a/sys/dev/sound/pcm/sound.h
+++ b/sys/dev/sound/pcm/sound.h
@@ -350,8 +350,6 @@ void snd_mtxassert(void *m);
 #define	snd_mtxunlock(m) mtx_unlock(m)
 
 typedef int (*sndstat_handler)(struct sbuf *s, device_t dev, int verbose);
-int sndstat_acquire(struct thread *td);
-int sndstat_release(struct thread *td);
 int sndstat_register(device_t dev, char *str, sndstat_handler handler);
 int sndstat_registerfile(char *str);
 int sndstat_unregister(device_t dev);