Re: [PATCH] fs/vboxsf: Replace kmap() with kmap_local_{page, folio}()

From: Matthew Wilcox
Date: Wed Jun 28 2023 - 23:08:32 EST


On Wed, Jun 28, 2023 at 07:23:54PM -0700, Ira Weiny wrote:
> Matthew Wilcox wrote:
> > Here's a more comprehensive read_folio patch. It's not at all
> > efficient, but then if we wanted an efficient vboxsf, we'd implement
> > vboxsf_readahead() and actually do an async call with deferred setting
> > of the uptodate flag. I can consult with anyone who wants to do all
> > this work.
> >
> > I haven't even compiled this, just trying to show the direction this
> > should take.
>
> I'm a bit confused. Is this progressing toward having the folio passed
> down to vboxsf_read() or just an expanded vboxsf_read_folio which can
> handle larger folios as well as fix the kmap?

This just handles large folios & switches to kmap_local_folio(). Doing
this properly is a _lot_ of work, and needs someone who can commit to
actually testing it.