linux-kernel - Re: [PATCH 03/16] mm: add vma_desc_size(), vma_desc

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Message-ID: <8edb13fc-e58d-4480-8c94-c321da0f4d8e@redhat.com>
Date: Mon, 8 Sep 2025 17:24:23 +0200
From: David Hildenbrand <david@...hat.com>
To: Jason Gunthorpe <jgg@...dia.com>,
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Subject: Re: [PATCH 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers

> 
>> I think we need to be cautious of scope here :) I don't want to
>> accidentally break things this way.
> 
> IMHO it is worth doing when you get into more driver places it is far
> more obvious why the VM_SHARED is being checked.
> 
>> OK I think a sensible way forward - How about I add desc_is_cowable() or
>> vma_desc_cowable() and only set this if I'm confident it's correct?
> 
> I'm thinking to call it vma_desc_never_cowable() as that is much much
> clear what the purpose is.

Secretmem wants no private mappings. So we should check exactly that, 
not whether we might have a cow mapping.

-- 
Cheers

David / dhildenb