Re: [RFC PATCH 7/8] mm/ioremap: Consider IOREMAP space in generic ioremap

I'm more focussed on powerpc32

+ Adding linuxppc-dev, someone else might help.

Le 16/10/2022 à 13:51, Arnd Bergmann a écrit :

On Sun, Oct 16, 2022, at 9:54 AM, Alexander Gordeev wrote:

quoted

On Wed, Oct 12, 2022 at 12:39:11PM +0200, Arnd Bergmann wrote:

quoted

"Some" means exactly powerpc64, right? It looks like microblaze
and powerpc32 still share some of this code, but effectively
just use the vmalloc area once the slab allocator is up.

Is the special case still useful for powerpc64 or could this be
changed to do it the same as everything else?

Or make it the other way around and set IOREMAP_START/IOREMAP_END
to VMALLOC_START/VMALLOC_END by default?

Sure, if there is a reason for actually making them different.
 From the git history, it appears that before commit 3d5134ee8341
("[POWERPC] Rewrite IO allocation & mapping on powerpc64"), the
ioremap() and vmalloc() handling was largely duplicated. Ben
cleaned it up by making most of the implementation shared but left
the separate address spaces.

My guess is that there was no technical reason for this, other
than having no reason to change the behavior at the time.

        Arnd