From:   Alejandro Colomar <alx.manpages@gmail.com>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Alejandro Colomar <alx.manpages@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Kees Cook <keescook@chromium.org>,
        Joe Perches <joe@perches.com>
Subject: [PATCH v2 10/20] linux/container_of.h: Remove unnecessary cast
Date:   Sat, 20 Nov 2021 14:00:53 +0100
Message-Id: <20211120130104.185699-11-alx.manpages@gmail.com>
In-Reply-To: <20211120130104.185699-1-alx.manpages@gmail.com>
References: <20211119113644.1600-1-alx.manpages@gmail.com>
 <20211120130104.185699-1-alx.manpages@gmail.com>
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Precedence: bulk

Casts are dangerous.
Moreover, (almost) everything converts to 'void *' implicitly,
with the exception of pointers to const.

Change the temporary to be const,
and therefore allow implicit conversion from everything.
Since we don't modify it,
this also adds safety.

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
 include/linux/container_of.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/container_of.h b/include/linux/container_of.h
index d1a66e72d246..682a2a606ee9 100644
--- a/include/linux/container_of.h
+++ b/include/linux/container_of.h
@@ -17,7 +17,7 @@
  *
  */
 #define container_of(ptr, type, member) ({				\
-	void *__mptr = (void *)(ptr);					\
+	const void *__mptr = (ptr);					\
 	static_assert(__same_type(*(ptr), memberof(type, member)) ||	\
 		      __same_type(*(ptr), void),			\
 		      "pointer type mismatch in container_of()");	\
-- 
2.33.1