On 24/06/21 12:06, Marc Zyngier wrote:

On Thu, 24 Jun 2021 09:58:00 +0100,
Nicholas Piggin [off-list ref] wrote:

quoted

Excerpts from David Stevens's message of June 24, 2021 1:57 pm:

quoted

From: David Stevens <redacted>
  out_unlock:
  	if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa))
  		read_unlock(&vcpu->kvm->mmu_lock);
  	else
  		write_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(pfn);
+	if (pfnpg.page)
+		put_page(pfnpg.page);
  	return r;
  }

How about

   kvm_release_pfn_page_clean(pfnpg);

I'm not sure. I always found kvm_release_pfn_clean() ugly, because it
doesn't mark the page 'clean'. I find put_page() more correct.

Something like 'kvm_put_pfn_page()' would make more sense, but I'm so
bad at naming things that I could just as well call it 'bob()'.

The best way to go would be to get rid of kvm_release_pfn_clean() and 
always go through a pfn_page.  Then we could or could not introduce 
wrappers kvm_put_pfn_page{,_dirty}.

I think for now it's best to limit the churn since these patches will go 
in the stable releases too, and clean up the resulting API once we have 
a clear idea of how all architectures are using kvm_pfn_page.

Paolo