linux-kernel - [PATCH v2] mm/damon: Remove redundant page validation

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Message-Id: <6d32f7d201b8970d53f51b6c5717d472aed2987c.1642386715.git.baolin.wang@linux.alibaba.com>
Date:   Mon, 17 Jan 2022 10:34:18 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     sj@...nel.org, akpm@...ux-foundation.org
Cc:     baolin.wang@...ux.alibaba.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] mm/damon: Remove redundant page validation

It will never get a NULL page by pte_page() as discussed in thread [1],
thus remove the redundant page validation to fix below Smatch static
checker warning.

    mm/damon/vaddr.c:405 damon_hugetlb_mkold()
    warn: 'page' can't be NULL.

[1] https://lore.kernel.org/linux-mm/20220106091200.GA14564@kili/

Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
Reviewed-by: SeongJae Park <sj@...nel.org>
---
Changes from v1:
 - Improve the commit message suggested by SeongJae.
 - Add reviewed-by tag from SeongJae.
---
 mm/damon/vaddr.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 89b6468d..8a52e00 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -402,9 +402,6 @@ static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
 	pte_t entry = huge_ptep_get(pte);
 	struct page *page = pte_page(entry);
 
-	if (!page)
-		return;
-
 	get_page(page);
 
 	if (pte_young(entry)) {
@@ -564,9 +561,6 @@ static int damon_young_hugetlb_entry(pte_t *pte, unsigned long hmask,
 		goto out;
 
 	page = pte_page(entry);
-	if (!page)
-		goto out;
-
 	get_page(page);
 
 	if (pte_young(entry) || !page_is_idle(page) ||
-- 
1.8.3.1