[LTP] [PATCH v4] syscalls/membarrier: Add membarrier() initial test

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> Fixes: #265
> 
> Initial test for membarrier() syscall. It tests all existing membarrier
> "commands" (or features), including the need (or not) for previous
> registration for the call to work.
> 
> Some features did not exist in older kernels and that is covered by
> skipping some calls, flagging test as skipped & okay, and forcing
> others, making sure that return codes and errno are set right in those
> cases.
> 
> Tests are done in a child process due to inexistent kernel interface to
> "unregister" the process from being affected by membarrier() call.
> 
> Signed-off-by: Rafael David Tinoco <rafael.tinoco@linaro.org>

Looks good to me.

We probably can drop linux/membarrier.h configure check, right?
(since v4 doesn't include it and unsupported kernel should
hit ENOSYS and TCONF)

Regards,
Jan