Re: [PATCH 41/45] include/uapi/sound/emu10k1.h: hide gpr_valid, tram_valid and code_valid in userspace

At Wed, 11 Mar 2015 10:46:29 +0100,
Arnd Bergmann wrote:

On Wednesday 11 March 2015 07:11:18 Takashi Iwai wrote:

quoted

At Wed, 11 Mar 2015 03:22:04 +0200,
Mikko Rapeli wrote:

quoted

On Tue, Feb 17, 2015 at 07:27:38AM +0100, Takashi Iwai wrote:

quoted

At Tue, 17 Feb 2015 00:05:44 +0100,
Mikko Rapeli wrote:

quoted

The DECLARE_BITMAP macro is not available in userspace headers.
Fixes userspace compile error:
error: expected specifier-qualifier-list before ‘DECLARE_BITMAP’

It's nonsense.  This results in an incompatible structure, thus ABI
would be broken completely (actually this will break the compile of
ld10k1).

None of the exported headers after 'make headers_install' have definition
of DECLARE_BITMAP macro. It is defined in include/linux/types.h which is
different from include/uapi/linux/types.h and missing this definition and
a few other things.

One option would be add DECLARE_BITMAP macro to include/uapi/linux/types.h
and add include/linux/bitops.h to uapi.

Thoughts?

Are there any other headers like that?  If this is the only one, leave
it as is.  The only program that reads this are some alsa-tools ones
and they have already own DECLARE_BITMAP() definition.  Adding the
extra definition here will even break the compilation out of sudden.

I think it's a worthy goal to have the header files be compilable
standalone,

In general yes, but this case is very minor issue:
- the file in question is for a hardware device-specific data
  definition,
- there are only two programs read this file, both can be built
  properly,
- and the device and the programs are very old, modifying such need
  extra care.

but I don't think we should make the DECLARE_BITMAP()
macro globally visible in user space, in particular because it will
clash with every instance in which user space has a macro of the
same name.

What we could do here is to add a private copy of the macro to emu10k1.h
under a different name, such as __EMU10K1_DECLARE_BITMAP().

Yes, it's a better option.


thanks,

Takashi