[PATCH v2] module: Fix selfAssignment cppcheck warning

From: Christophe Leroy
Date: Sun Jun 12 2022 - 11:22:33 EST


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.

Transform strict_align() macro into an inline function. It will
allow type checking and avoid the selfAssignment warning.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
kernel/module/internal.h | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index bc5507ab8450..ec104c2950c3 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -11,6 +11,7 @@
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
+#include <linux/mm.h>

#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
@@ -30,11 +31,13 @@
* to ensure complete separation of code and data, but
* only when CONFIG_STRICT_MODULE_RWX=y
*/
-#ifdef CONFIG_STRICT_MODULE_RWX
-# define strict_align(X) PAGE_ALIGN(X)
-#else
-# define strict_align(X) (X)
-#endif
+static inline unsigned int strict_align(unsigned int size)
+{
+ if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+ return PAGE_ALIGN(size);
+ else
+ return size;
+}

extern struct mutex module_mutex;
extern struct list_head modules;
--
2.35.3