Re: [PATCH v2 03/46] mm: Add kmap_local_folio()

[Christoph Hellwig]

On Tue, Jun 22, 2021 at 01:15:08PM +0100, Matthew Wilcox (Oracle) wrote:
> This allows us to map a portion of a folio.  Callers can only expect
> to access up to the next page boundary.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>

This looks sensible to me:

Reviewed-by: Christoph Hellwig <hch@xxxxxx>

While we're at it:  flushing incoherent mappings for use with kmap
has been a complete mess.  I've been trying to fix this with
kunmap_local_dirty, but that could use another review, as well as a
folio version probably give that one prime use case of folios is to have
them mapped into userspace.