diff mbox series

[04/11] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd

Message ID 53fbc9d-891e-46b2-cb4b-468c3b19238e@google.com (mailing list archive)
State New
Headers show
Series mm: page_vma_mapped_walk() cleanup and THP fixes | expand

Commit Message

Hugh Dickins June 10, 2021, 6:40 a.m. UTC
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(-)

Comments

Kirill A. Shutemov June 10, 2021, 9:10 a.m. UTC | #1
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>
Peter Xu June 10, 2021, 2:31 p.m. UTC | #2
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 mbox series

Patch

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);