Re: [PATCH v3 1/1] selftests/mm/uffd: Refactor non-composite global vars into struct

[Ujwal Kundur <ujwal.kundur@gmail.com>]

> Sounds like that's your issue - for the kernel, tab is supposed to be
> as wide as 8 spaces, not 4.

That fixed it, thanks! I've gone through the diff and made sure there
are no longer any inconsistent indents.

> I'm afraid I'm too ignorant of this code to be able to suggest something
> good here. But, can we just remove the comment and plumb the gopts
> through to uffd_poll_thread()->uffd_handle_page_fault()->__copy_page()?
>
> This is not pretty but it lets us remove the global vars which is
> clearly a step in the right direction.

Perhaps Andrew can weigh in? If I understood this correctly, we're
trying to assert that retrying a successful UFFDIO_COPY operation
always results in EEXIST. This is being done in a somewhat racy
fashion where a flag (test_uffdio_copy_eexist) is set every 10 seconds
using alarm(2). IMO this is a flaky test, we should either:
- remove this variable and associated logic entirely (preferred)
- use a probability function to set this a % of the time instead of
every 10 seconds
- use an async library that can replace the implementation without the
use of global vars