linux-kernel - [PATCH] ocfs2: drop a VLA in ocfs2_orphan

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Message-Id: <1520970710-19732-1-git-send-email-s.mesoraca16@gmail.com>
Date:   Tue, 13 Mar 2018 20:51:50 +0100
From:   Salvatore Mesoraca <s.mesoraca16@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-hardening@...ts.openwall.com,
        Joel Becker <jlbec@...lplan.org>,
        Kees Cook <keescook@...omium.org>,
        Mark Fasheh <mfasheh@...sity.com>,
        Salvatore Mesoraca <s.mesoraca16@...il.com>
Subject: [PATCH] ocfs2: drop a VLA in ocfs2_orphan_del()

Avoid a VLA[1] by using a real constant expression instead of a variable.
The compiler should be able to optimize the original code and avoid using
an actual VLA. Anyway this change is useful because it will avoid a false
positive with -Wvla, it might also help the compiler generating better
code.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Salvatore Mesoraca <s.mesoraca16@...il.com>
---
 fs/ocfs2/namei.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index c801edd..41ef356 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -2332,8 +2332,7 @@ int ocfs2_orphan_del(struct ocfs2_super *osb,
 		     struct buffer_head *orphan_dir_bh,
 		     bool dio)
 {
-	const int namelen = OCFS2_DIO_ORPHAN_PREFIX_LEN + OCFS2_ORPHAN_NAMELEN;
-	char name[namelen + 1];
+	char name[OCFS2_DIO_ORPHAN_PREFIX_LEN + OCFS2_ORPHAN_NAMELEN + 1];
 	struct ocfs2_dinode *orphan_fe;
 	int status = 0;
 	struct ocfs2_dir_lookup_result lookup = { NULL, };
-- 
1.9.1