Re: [PATCH v2 2/2] mm: prevent gup_fast from racing with COW during fork

[Ahmed S. Darwish]

On Mon, Nov 02, 2020 at 08:25:32PM -0400, Jason Gunthorpe wrote:
> On Tue, Nov 03, 2020 at 01:17:12AM +0100, Ahmed S. Darwish wrote:
>
> > Please stick with the official exported API: raw_write_seqcount_begin().
>
> How did you know this was 'offical exported API' ??
>

All the official exported seqlock.h APIs are marked with verbose
kernel-doc annotations on top. The rest are internal...

> > Exactly. '*_seqcount_t_*' is a seqlock.h implementation detail, and it
> > has _zero_ relevance to what is discussed in this thread actually.
>
> Add some leading __'s to them?
>

It's a bit more complicated than just adding some "__" prefixes, due to
the massive compile-time polymorphism done through _Generic().

The '*_seqcount_t_*' format was the best we could come up with to
distinguish (again, for internal seqlock.h code) between macros taking
all seqcount_LOCKNAME_t types, and macros/functions taking only plain
seqcount_t.

Thanks,

--
Ahmed S. Darwish
Linutronix GmbH