linux-kernel - [PATCH] mm/madvise: Use vma_lookup() instead of find

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Date:   Tue, 4 Apr 2023 17:45:15 +0800
From:   Peng Zhang <zhangpeng362@...wei.com>
To:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <akpm@...ux-foundation.org>
CC:     <wangkefeng.wang@...wei.com>, <sunnanyong@...wei.com>,
        ZhangPeng <zhangpeng362@...wei.com>
Subject: [PATCH] mm/madvise: Use vma_lookup() instead of find_vma()

From: ZhangPeng <zhangpeng362@...wei.com>

Using vma_lookup() verifies the address is contained in the found vma.
This results in easier to read the code.

Signed-off-by: ZhangPeng <zhangpeng362@...wei.com>
---
 mm/madvise.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 340125d08c03..405a2c4a0a18 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -852,21 +852,9 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
 		*prev = NULL; /* mmap_lock has been dropped, prev is stale */
 
 		mmap_read_lock(mm);
-		vma = find_vma(mm, start);
+		vma = vma_lookup(mm, start);
 		if (!vma)
 			return -ENOMEM;
-		if (start < vma->vm_start) {
-			/*
-			 * This "vma" under revalidation is the one
-			 * with the lowest vma->vm_start where start
-			 * is also < vma->vm_end. If start <
-			 * vma->vm_start it means an hole materialized
-			 * in the user address space within the
-			 * virtual range passed to MADV_DONTNEED
-			 * or MADV_FREE.
-			 */
-			return -ENOMEM;
-		}
 		/*
 		 * Potential end adjustment for hugetlb vma is OK as
 		 * the check below keeps end within vma.
-- 
2.25.1