Re: [userns:userns-always-map-user-v45 80/99] fs/namespace.c:2290:1: error: unknown type name 'atomi

[Fengguang Wu <fengguang.wu@intel.com>]

On Sun, Aug 12, 2012 at 11:56:45PM -0700, Eric W. Biederman wrote:
> Fengguang Wu <fengguang.wu@intel.com> writes:
> 
> > Hi Geert,
> >
> > This is the build error I get, on Eric's userns tree.
> >
> > tree:   git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git userns-always-map-user-v45
> > head:   38a0b1b84f5f613ff4e01fffda27f87d4cb2b649
> > commit: 5ea9fc30545b658380d4794340227fe821b83701 [80/99] vfs: Add setns support for the mount namespace
> > config: m68k-m5475evb_defconfig (attached as .config)
> >
> > All related error/warning messages:
> >
> > fs/namespace.c:2290:1: error: unknown type name 'atomic64_t'
> > fs/namespace.c:2290:1: error: implicit declaration of function 'ATOMIC64_INIT' [-Werror=implicit-function-declaration]
> > fs/namespace.c:2290:1: error: initializer element is not constant
> > fs/namespace.c: In function 'alloc_mnt_ns':
> > fs/namespace.c:2299:2: error: implicit declaration of function 'atomic64_add_return' [-Werror=implicit-function-declaration]
> > cc1: some warnings being treated as errors
> 
> Fengguang is m68k the only place you are seeing build failures?

Yes.

> Exactly how I get a 64bit counter in that code path is not terribly
> important.  I picked an atomic64_t because it looked simple and cheap.

Fair enough. As long as it's not in hot code path, it definitely helps
to use simple solutions.

> If this is limited to a couple of m68k sub-arches I will let you guys
> finish fixing this up so people can depend on atomic64_t being
> available.  Otherwise it probably makes sense to go to with a different
> abstraction.

I'd suggest to fix it in m68k and make atomic64_t generally available.

Thanks,
Fengguang