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authorHugh Dickins <hughd@google.com>2021-06-24 18:39:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-24 19:40:53 -0700
commit3306d3119ceacc43ea8b141a73e21fea68eec30c (patch)
tree3f3860084e8821788f151bf6baad91c91605b30d
parent6d0fd5987657cb0c9756ce684e3a74c0f6351728 (diff)
mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd
page_vma_mapped_walk() cleanup: re-evaluate pmde after taking lock, then use it in subsequent tests, instead of repeatedly dereferencing pointer. Link: https://lkml.kernel.org/r/53fbc9d-891e-46b2-cb4b-468c3b19238e@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_vma_mapped.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 7c0504641fb8..8f972b05a0de 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -191,18 +191,19 @@ restart:
pmde = READ_ONCE(*pvmw->pmd);
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);