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Date: Mon, 18 Mar 2024 13:16:23 -0300
From: Jason Gunthorpe <jgg@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
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	Matthew Wilcox <willy@infradead.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"x86@kernel.org" <x86@kernel.org>, Mike Rapoport <rppt@kernel.org>,
	Muchun Song <muchun.song@linux.dev>,
	"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>
Subject: Re: [PATCH 11/13] mm/treewide: Replace pXd_huge() with pXd_leaf()
Message-ID: <20240318161623.GB5825@nvidia.com>
References: <20240313214719.253873-1-peterx@redhat.com>
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On Thu, Mar 14, 2024 at 08:59:22AM -0400, Peter Xu wrote:

> > > --- a/mm/hmm.c
> > > +++ b/mm/hmm.c
> > > @@ -429,7 +429,7 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
> > >   		return hmm_vma_walk_hole(start, end, -1, walk);
> > >   	}
> > >   
> > > -	if (pud_huge(pud) && pud_devmap(pud)) {
> > > +	if (pud_leaf(pud) && pud_devmap(pud)) {
> > 
> > Didn't previous patch say devmap implies leaf ? Or is it only for GUP ?
> 
> This is an extra safety check that I didn't remove.  Devmap used separate
> bits even though I'm not clear on why.  It should still imply a leaf though.

Yes, something is very wrong if devmap is true on non-leaf..

Jason