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

[John Hubbard]

On 11/2/20 4:41 PM, Ahmed S. Darwish wrote:
> 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...

OK, but no one here was able to deduce that, probably because there is not
enough consistency throughout the kernel to be able to assume such things--even
though your seqlock project is internally consistent. It's just not *quite*
enough communication.

I think if we added the following it would be very nice:

a) Short comments to the "unofficial and internal" routines, identifying them as
such, and

b) Short comments to the "official API for general use", also identifying
those as such.

c) A comment about what makes "raw" actually raw, for seqlock.


Since I'm proposing new work, I'll also offer to help, perhaps by putting together
a small patch to get it kicked off, if you approve of the idea.

thanks,
--
John Hubbard
NVIDIA