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

[Dan Williams]

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:

d92576f1167c dax: does not work correctly with virtual aliasing caches

Otherwise, you can add:

Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>