Re: [Linux-fbdev-devel] [PATCH] video: arch specific page protection support for deferred io

[Paul M. <le...@li...>]

On Wed, Jun 24, 2009 at 07:56:47PM -0700, Andrew Morton wrote:
> On Wed, 24 Jun 2009 19:54:13 +0900 Magnus Damm <mag...@gm...> wrote:
> 
> > From: Magnus Damm <da...@ig...>
> > 
> > This patch adds arch specific page protection support to deferred io.
> > 
> > Instead of overwriting the info->fbops->mmap pointer with the
> > deferred io specific mmap callback, modify fb_mmap() to include
> > a #ifdef wrapped call to fb_deferred_io_mmap().  The function
> > fb_deferred_io_mmap() is extended to call fb_pgprotect() in the
> > case of non-vmalloc() frame buffers.
> > 
> > With this patch uncached deferred io can be used together with
> > the sh_mobile_lcdcfb driver. Without this patch arch specific
> > page protection code in fb_pgprotect() never gets invoked with
> > deferred io.
> > 
> > Signed-off-by: Magnus Damm <da...@ig...>
> > ---
> > 
> >  For proper runtime operation with uncached vmas make sure
> >  "[PATCH][RFC] mm: uncached vma support with writenotify"
> >  is applied. There are no merge order dependencies.
> 
> So this is dependent upon a patch which is in your tree, which is in
> linux-next?
> 
This patch is not in the sh tree, either, we wanted it to go via -mm, but
it has the issue that it depends on pgprot_noncached() being generally
defined, so there is a bit of an ordering mess. It could be re-posted
with an ifdef pgprot_noncached to get it merged while we wait for the
outstanding architectures to catch up, and this is indeed what the bulk
of the in-tree pgprot_noncached() users in generic places end up doing
already.

Of course I can take both through the sh tree once people are happy with
the patches.