compat_ioctl: remove translation for sound ioctls

The SNDCTL_* and SOUND_* commands are the old OSS user interface.

I checked all the sound ioctl commands listed in fs/compat_ioctl.c
to see if we still need the translation handlers. Here is what I
found:

- sound/oss/ is (almost) gone from the kernel, this is what actually
  needed all the translations
- The ALSA emulation for OSS correctly handles all compat_ioctl
  commands already.
- sound/oss/dmasound/ is the last holdout of the original OSS code,
  this is only used on arch/m68k, which has no 64-bit mode and
  hence needs no compat handlers
- arch/um/drivers/hostaudio_kern.c may run in 64-bit mode with
  32-bit x86 user space underneath it. This rare corner case is
  the only one that still needs the compat handlers.

By adding a simple redirect of .compat_ioctl to .unlocked_ioctl in the
UML driver, we can remove all the COMPATIBLE_IOCTL() annotations without
a change in functionality. For completeness, I'm adding the same thing
to the dmasound file, knowing that it makes no difference.

The compat_ioctl list contains one comment about SNDCTL_DSP_MAPINBUF and
SNDCTL_DSP_MAPOUTBUF, which actually would need a translation handler
if implemented. However, the native implementation just returns -EINVAL,
so we don't care.

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index f57c610d7523..13db77771f0f 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -2717,6 +2717,10 @@ static long snd_pcm_oss_ioctl(struct file *file, unsigned int cmd, unsigned long
 static long snd_pcm_oss_ioctl_compat(struct file *file, unsigned int cmd,
 				     unsigned long arg)
 {
+	/*
+	 * Everything is compatbile except SNDCTL_DSP_MAPINBUF/SNDCTL_DSP_MAPOUTBUF,
+	 * which are not implemented for the native case either
+	 */
 	return snd_pcm_oss_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 }
 #else