linux-kernel - [PATCH] module: Fix selfAssignment cppcheck warning

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Date:   Sun, 12 Jun 2022 12:17:25 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Luis Chamberlain <mcgrof@...nel.org>, linux-modules@...r.kernel.org
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, kernel test robot <lkp@...el.com>
Subject: [PATCH] module: Fix selfAssignment cppcheck warning

cppcheck reports the following warnings:

kernel/module/main.c:1455:26: warning: Redundant assignment of 'mod->core_layout.size' to itself. [selfAssignment]
   mod->core_layout.size = strict_align(mod->core_layout.size);
                         ^
kernel/module/main.c:1489:26: warning: Redundant assignment of 'mod->init_layout.size' to itself. [selfAssignment]
   mod->init_layout.size = strict_align(mod->init_layout.size);
                         ^
kernel/module/main.c:1493:26: warning: Redundant assignment of 'mod->init_layout.size' to itself. [selfAssignment]
   mod->init_layout.size = strict_align(mod->init_layout.size);
                         ^
kernel/module/main.c:1504:26: warning: Redundant assignment of 'mod->init_layout.size' to itself. [selfAssignment]
   mod->init_layout.size = strict_align(mod->init_layout.size);
                         ^
kernel/module/main.c:1459:26: warning: Redundant assignment of 'mod->data_layout.size' to itself. [selfAssignment]
   mod->data_layout.size = strict_align(mod->data_layout.size);
                         ^
kernel/module/main.c:1463:26: warning: Redundant assignment of 'mod->data_layout.size' to itself. [selfAssignment]
   mod->data_layout.size = strict_align(mod->data_layout.size);
                         ^
kernel/module/main.c:1467:26: warning: Redundant assignment of 'mod->data_layout.size' to itself. [selfAssignment]
   mod->data_layout.size = strict_align(mod->data_layout.size);
                         ^

This is due to strict_align() being a no-op when
CONFIG_STRICT_MODULE_RWX is not selected.

Change strict_align() to a bitwise OR with 0 in order to feint cppcheck.

Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 kernel/module/internal.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index bc5507ab8450..8396d5f5daa0 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -33,7 +33,8 @@
 #ifdef CONFIG_STRICT_MODULE_RWX
 # define strict_align(X) PAGE_ALIGN(X)
 #else
-# define strict_align(X) (X)
+/* OR with zero to avoid cppcheck selfAssignment warning */
+# define strict_align(X) ((X) | 0)
 #endif
 
 extern struct mutex module_mutex;
-- 
2.35.3