Re: [PATCH] btrfs: Replace kmap() with kmap_local_page() in zstd.c

From: Ira Weiny
Date: Tue Jun 14 2022 - 13:07:52 EST


On Tue, Jun 14, 2022 at 06:28:48PM +0200, Fabio M. De Francesco wrote:
> On martedì 14 giugno 2022 16:25:21 CEST David Sterba wrote:
> > On Tue, Jun 14, 2022 at 01:22:50AM +0200, Fabio M. De Francesco wrote:
> > > On lunedì 13 giugno 2022 20:39:13 CEST David Sterba wrote:
> > > > On Sat, Jun 11, 2022 at 03:52:03PM +0200, Fabio M. De Francesco
> >

[snip]

> > > A better solution is changing the prototype of __kunmap_local(); I
> > > suppose that Andrew won't object, but who knows?
> > >
> > > (+Cc Andrew Morton).
> > >
> > > I was waiting for your comments. At now I've done about 15 conversions
> > > across the kernel but it's the first time I had to pass a pointer to
> const
> > > void to kunmap_local(). Therefore, I was not sure if changing the API
> were
> > > better suited (however I have already discussed this with Ira).
> >
> > IMHO it should be fixed in the API.
> >
> I agree with you in full.
>
> At the same time when you sent this email I submitted a patch to change
> kunmap_local() and kunmap_atomic().
>
> After Andrew takes them I'll send v2 of this patch to zstd.c without those
> unnecessary casts.

David,

Would you be willing to take this through your tree as a pre-patch to the kmap
changes in btrfs?

That would be easier for Fabio and probably you and Andrew in the long run.

Ira

>
> Thanks for your review,
>
> Fabio
>
>
>