linux-kernel - [PATCH] damon: Use pmdp_get instead of drect dereferencing pmd.

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Message-Id: <20230727183745.682880-1-ppbuk5246@gmail.com>
Date:   Fri, 28 Jul 2023 03:37:45 +0900
From:   Levi Yun <ppbuk5246@...il.com>
To:     sj@...nel.org, akpm@...ux-foundation.org
Cc:     damon@...ts.linux.dev, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Levi Yun <ppbuk5246@...il.com>
Subject: [PATCH] damon: Use pmdp_get instead of drect dereferencing pmd.

As ptep_get, Use the pmdp_get wrapper when we accessing pmdval
instead of direct dereferencing pmd.

Signed-off-by: Levi Yun <ppbuk5246@...il.com>
---
 mm/damon/ops-common.c |  2 +-
 mm/damon/paddr.c      |  2 +-
 mm/damon/vaddr.c      | 22 ++++++++++++++--------
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index e940802a15a4..ac1c3fa80f98 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -54,7 +54,7 @@ void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr
 void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	struct folio *folio = damon_get_folio(pmd_pfn(*pmd));
+	struct folio *folio = damon_get_folio(pmd_pfn(pmdp_get(pmd)));
 
 	if (!folio)
 		return;
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 40801e38fcf0..909db25efb35 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -94,7 +94,7 @@ static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
 				mmu_notifier_test_young(vma->vm_mm, addr);
 		} else {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-			*accessed = pmd_young(*pvmw.pmd) ||
+			*accessed = pmd_young(pmdp_get(pvmw.pmd)) ||
 				!folio_test_idle(folio) ||
 				mmu_notifier_test_young(vma->vm_mm, addr);
 #else
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 2fcc9731528a..82f7865719fe 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -301,16 +301,19 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr,
 		unsigned long next, struct mm_walk *walk)
 {
 	pte_t *pte;
+	pmd_t pmde;
 	spinlock_t *ptl;
 
-	if (pmd_trans_huge(*pmd)) {
+	if (pmd_trans_huge(pmdp_get_lockless(pmd))) {
 		ptl = pmd_lock(walk->mm, pmd);
-		if (!pmd_present(*pmd)) {
+		pmde = pmdp_get(pmd);
+
+		if (!pmd_present(pmde)) {
 			spin_unlock(ptl);
 			return 0;
 		}
 
-		if (pmd_trans_huge(*pmd)) {
+		if (pmd_trans_huge(pmde)) {
 			damon_pmdp_mkold(pmd, walk->vma, addr);
 			spin_unlock(ptl);
 			return 0;
@@ -434,26 +437,29 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
 {
 	pte_t *pte;
 	pte_t ptent;
+	pmd_t pmde;
 	spinlock_t *ptl;
 	struct folio *folio;
 	struct damon_young_walk_private *priv = walk->private;
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	if (pmd_trans_huge(*pmd)) {
+	if (pmd_trans_huge(pmdp_get_lockless(pmd))) {
 		ptl = pmd_lock(walk->mm, pmd);
-		if (!pmd_present(*pmd)) {
+		pmde = pmdp_get(pmd);
+
+		if (!pmd_present(pmde)) {
 			spin_unlock(ptl);
 			return 0;
 		}
 
-		if (!pmd_trans_huge(*pmd)) {
+		if (!pmd_trans_huge(pmde)) {
 			spin_unlock(ptl);
 			goto regular_page;
 		}
-		folio = damon_get_folio(pmd_pfn(*pmd));
+		folio = damon_get_folio(pmd_pfn(pmde));
 		if (!folio)
 			goto huge_out;
-		if (pmd_young(*pmd) || !folio_test_idle(folio) ||
+		if (pmd_young(pmde) || !folio_test_idle(folio) ||
 					mmu_notifier_test_young(walk->mm,
 						addr))
 			priv->young = true;
-- 
2.37.2