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This may > lead to inproper situation. > Could you elaborate a more on the improper situation? > This patch fixes commit 65edfda6f3f2 ("mm/rmap: extend rmap and migration > support device-private entries") by following the same pattern as > pmd_trans_huge() and pmd_is_migration_entry(). > > Fixes: 65edfda6f3f2 ("mm/rmap: extend rmap and migration support device-private entries") > Signed-off-by: Wei Yang > Cc: David Hildenbrand > Cc: Balbir Singh > Cc: SeongJae Park > Cc: Zi Yan > Cc: Lorenzo Stoakes > Cc: > --- > mm/page_vma_mapped.c | 34 +++++++++++++++++++++++----------- > 1 file changed, 23 insertions(+), 11 deletions(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index a4d52fdb3056..5d337ea43019 100644 > --- a/mm/page_vma_mapped.c > +++ b/mm/page_vma_mapped.c > @@ -269,21 +269,33 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > spin_unlock(pvmw->ptl); > pvmw->ptl = NULL; > } else if (!pmd_present(pmde)) { > - const softleaf_t entry = softleaf_from_pmd(pmde); > + softleaf_t entry = softleaf_from_pmd(pmde); > > if (softleaf_is_device_private(entry)) { > pvmw->ptl = pmd_lock(mm, pvmw->pmd); > - return true; > - } > - > - if ((pvmw->flags & PVMW_SYNC) && > - thp_vma_suitable_order(vma, pvmw->address, > - PMD_ORDER) && > - (pvmw->nr_pages >= HPAGE_PMD_NR)) > - sync_with_folio_pmd_zap(mm, pvmw->pmd); > + entry = softleaf_from_pmd(*pvmw->pmd); > + > + if (softleaf_is_device_private(entry)) { Do we need to check softleaf_is_device_private() twice, can't we hold the pmd lock and check once? > + if (pvmw->flags & PVMW_MIGRATION) > + return not_found(pvmw); Double check, do we want to skip migration pte's (from remove_migration_pte) > + if (!check_pmd(softleaf_to_pfn(entry), pvmw)) > + return not_found(pvmw); > + return true; > + } > > - step_forward(pvmw, PMD_SIZE); > - continue; > + /* THP pmd was split under us: handle on pte level */ > + spin_unlock(pvmw->ptl); > + pvmw->ptl = NULL; > + } else { > + if ((pvmw->flags & PVMW_SYNC) && > + thp_vma_suitable_order(vma, pvmw->address, > + PMD_ORDER) && > + (pvmw->nr_pages >= HPAGE_PMD_NR)) > + sync_with_folio_pmd_zap(mm, pvmw->pmd); > + > + step_forward(pvmw, PMD_SIZE); > + continue; > + } > } > if (!map_pte(pvmw, &pmde, &ptl)) { > if (!pvmw->pte) How was this tested? Did you run hmm-tests? Is there a broken user space that caught the issue? Balbir Singh