linux-kernel - [PATCH] mm/memory_failure: Fix the missing pte

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Date:   Thu, 23 Sep 2021 20:26:42 +0800
From:   Qi Zheng <zhengqi.arch@...edance.com>
To:     naoya.horiguchi@....com, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        songmuchun@...edance.com, Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH] mm/memory_failure: Fix the missing pte_unmap() call

The paired pte_unmap() call is missing before the
dev_pagemap_mapping_shift() returns. So fix it.

Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
---
 mm/memory-failure.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e2984c123e7e..4e5419f16fd4 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -306,6 +306,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
 		struct vm_area_struct *vma)
 {
 	unsigned long address = vma_address(page, vma);
+	unsigned long ret = 0;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
@@ -330,10 +331,12 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
 		return PMD_SHIFT;
 	pte = pte_offset_map(pmd, address);
 	if (!pte_present(*pte))
-		return 0;
+		goto unmap;
 	if (pte_devmap(*pte))
-		return PAGE_SHIFT;
-	return 0;
+		ret = PAGE_SHIFT;
+unmap:
+	pte_unmap(pte);
+	return ret;
 }
 
 /*
-- 
2.11.0