Re: `io{re,un}map()` build error in s390 under `!CONFIG_HAS_IOMEM`

On Mon, Aug 03, 2026 at 10:09:08PM +0200, Danilo Krummrich wrote:
> On Mon Aug 3, 2026 at 9:56 PM CEST, Arnd Bergmann wrote:
> > In theory you should be able to use rust code without PCI MMIO
> > support, but I can't see any practical downsides to making rust
> > 'depends on HAS_MMIO' to avoid having to add those #ifdef.
> 
> I think the implications should be minor without making Rust depend on
> CONFIG_HAS_IOMEM.
> 
> I just sent out a fix [1]; the only annoying part is [2], but we should change
> those doc-tests anyway. For the one in rust/kernel/io.rs we already did in
> driver-core-next.
> 
> [1] https://lore.kernel.org/driver-core/[email protected]/
> [2] https://lore.kernel.org/driver-core/[email protected]/

I'm wondering if it would make sense to make HAS_IOMEM always available
on s390, even though it doesn't make too much sense without PCI.
But at least it would make s390 again a bit less special.

Niklas, Gerd?