On Sat, Sep 08, 2018 at 04:28:09PM +0200, Arnd Bergmann wrote:
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.
diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c index 7f9dbdbc4eb7..0278a642a622 100644 --- a/arch/um/drivers/hostaudio_kern.c +++ b/arch/um/drivers/hostaudio_kern.c @@ -298,6 +298,7 @@ static const struct file_operations hostaudio_fops = { .write = hostaudio_write, .poll = hostaudio_poll, .unlocked_ioctl = hostaudio_ioctl,
- .compat_ioctl = hostaudio_ioctl,
Umm... OK, seeing that it's not going to be used on s390... It's still not quite right, though, and I'm afraid that places where we have the same ->unlocked_ioctl and ->compat_ioctl need an audit - there probably had been other folks who'd stepped into the same.