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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 06, 2024 at 06:41:35PM +0800, peterx@redhat.com wrote: > From: Peter Xu > > Swap pud entries do not always return true for pud_huge() for all archs. > x86 and sparc (so far) allow it, but all the rest do not accept a swap > entry to be reported as pud_huge(). So it's not safe to check swap entries > within pud_huge(). Check swap entries before pud_huge(), so it should be > always safe. > > This is the only place in the kernel that (IMHO, wrongly) relies on > pud_huge() to return true on pud swap entries. The plan is to cleanup > pXd_huge() to only report non-swap mappings for all archs. > > Cc: Alistair Popple > Signed-off-by: Peter Xu > --- > mm/hmm.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) Reviewed-by: Jason Gunthorpe > @@ -424,7 +424,7 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, > walk->action = ACTION_CONTINUE; > > pud = READ_ONCE(*pudp); > - if (pud_none(pud)) { > + if (pud_none(pud) || !pud_present(pud)) { Isn't this a tautology? pud_none always implies !present() ? Jason _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel