linux-kernel - [PATCH 7/7] f2fs: avoid casted negative value as shrink count

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Message-Id: <20161011143136.2107-7-chao@kernel.org>
Date:   Tue, 11 Oct 2016 22:31:36 +0800
From:   Chao Yu <chao@...nel.org>
To:     jaegeuk@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Chao Yu <yuchao0@...wei.com>
Subject: [PATCH 7/7] f2fs: avoid casted negative value as shrink count

From: Chao Yu <yuchao0@...wei.com>

This patch makes sure it returns a positive value instead of a probable
casted negative value as shrink count.

Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
 fs/f2fs/shrinker.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
index 8b0a112..e1220f2 100644
--- a/fs/f2fs/shrinker.c
+++ b/fs/f2fs/shrinker.c
@@ -21,14 +21,16 @@ static unsigned int shrinker_run_no;
 
 static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
 {
-	return NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
+	long count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
+
+	return count > 0 ? count : 0;
 }
 
 static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
 {
-	if (NM_I(sbi)->free_nid_cnt > MAX_FREE_NIDS)
-		return NM_I(sbi)->free_nid_cnt - MAX_FREE_NIDS;
-	return 0;
+	long count = NM_I(sbi)->free_nid_cnt - MAX_FREE_NIDS;
+
+	return count > 0 ? count : 0;
 }
 
 static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
-- 
2.10.1