Re: [PATCH v4 02/10] PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE

[Matt Evans <matt@ozlabs.org>]

Hi Logan,

On 02/07/2026 21:34, Logan Gunthorpe wrote:
> 
> 
> On 2026-07-02 10:44 a.m., Matt Evans wrote:
>>> So maybe at this point it's fine to enable this on 32bit systems and we
>>> can remove this requirement. However, I think we should do that
>>> explicitly in its own patch, not hide it in this refactoring patch.
>>
>> Your question does prove it's too stealthy as-is. :)  PCI_P2PDMA still
>> can't be enabled on 32-bit systems because of its ZONE_DEVICE -> 
>> MEMORY_HOTPLUG -> 64BIT dependency.  So we're not enabling 32-bit 
>> support for PCI_P2PDMA here, but it's not obvious and so I'll re-add the 
>> `depends on 64BIT`.  At least then it won't be enabled without intention 
>> if someone enables ZONE_DEVICE on 32-bit systems...
> 
> Ok, that all makes sense to me. I would be good with removing the 64BIT
> dependency (as it is is a bit confusing as is) but I think adding
> another patch would be appropriate with some of the commit message notes
> you mentioned in your emails.
> 
> Besides that, I think you can add to this patch:
> 
> Reviewed-by: Logan Gunthorpe <logang@deltatee.com>

Thanks for that.  On second reading, just want to check with you:

I'm intending to repost _retaining_ the 64BIT dependency (i.e. revert
its removal) for simplicity's sake.  Then we can follow up separatey
(outside this series) with a cleanup patch to remove 64BIT, explain,
examine other dependencies etc. as you suggest.  Works for you?

(I want to reduce the diff in this series, and revert since this isn't
truly necessary && wasn't entirely obvious.)

Cheers,


Matt