Re: [PATCH v4 2/6] dax: fix cache flush on PMD-mapped pages

[Muchun Song]

On Thu, Mar 10, 2022 at 8:06 AM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> On Wed, Mar 2, 2022 at 12:29 AM Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
> >
> > The flush_cache_page() only remove a PAGE_SIZE sized range from the cache.
> > However, it does not cover the full pages in a THP except a head page.
> > Replace it with flush_cache_range() to fix this issue.
>
> This needs to clarify that this is just a documentation issue with the
> respect to properly documenting the expected usage of cache flushing
> before modifying the pmd. However, in practice this is not a problem
> due to the fact that DAX is not available on architectures with
> virtually indexed caches per:

Right. I'll add this into the commit log.

>
> d92576f1167c dax: does not work correctly with virtual aliasing caches
>
> Otherwise, you can add:
>
> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>

Thanks.