| Message ID | 53fbc9d-891e-46b2-cb4b-468c3b19238e@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: page_vma_mapped_walk() cleanup and THP fixes | expand |
On Wed, Jun 09, 2021 at 11:40:08PM -0700, Hugh Dickins wrote: > page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then > use it in subsequent tests, instead of repeatedly dereferencing pointer. > > Signed-off-by: Hugh Dickins <hughd@google.com> > Cc: <stable@vger.kernel.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
On Wed, Jun 09, 2021 at 11:40:08PM -0700, Hugh Dickins wrote: > page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then > use it in subsequent tests, instead of repeatedly dereferencing pointer. > > Signed-off-by: Hugh Dickins <hughd@google.com> > Cc: <stable@vger.kernel.org> Reviewed-by: Peter Xu <peterx@redhat.com>
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 973c3c4e72cc..81000dd0b5da 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -194,18 +194,19 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) { pvmw->ptl = pmd_lock(mm, pvmw->pmd); - if (likely(pmd_trans_huge(*pvmw->pmd))) { + pmde = *pvmw->pmd; + if (likely(pmd_trans_huge(pmde))) { if (pvmw->flags & PVMW_MIGRATION) return not_found(pvmw); - if (pmd_page(*pvmw->pmd) != page) + if (pmd_page(pmde) != page) return not_found(pvmw); return true; - } else if (!pmd_present(*pvmw->pmd)) { + } else if (!pmd_present(pmde)) { if (thp_migration_supported()) { if (!(pvmw->flags & PVMW_MIGRATION)) return not_found(pvmw); - if (is_migration_entry(pmd_to_swp_entry(*pvmw->pmd))) { - swp_entry_t entry = pmd_to_swp_entry(*pvmw->pmd); + if (is_migration_entry(pmd_to_swp_entry(pmde))) { + swp_entry_t entry = pmd_to_swp_entry(pmde); if (migration_entry_to_page(entry) != page) return not_found(pvmw);
page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then use it in subsequent tests, instead of repeatedly dereferencing pointer. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> --- mm/page_vma_mapped.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)