From:   Alejandro Colomar <alx.manpages@gmail.com>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Alejandro Colomar <alx.manpages@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Corey Minyard <cminyard@mvista.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 01/17] linux/container_of.h: Add memberof(T, m)
Date:   Fri, 19 Nov 2021 12:36:29 +0100
Message-Id: <20211119113644.1600-2-alx.manpages@gmail.com>
In-Reply-To: <20211119113644.1600-1-alx.manpages@gmail.com>
References: <20211119113644.1600-1-alx.manpages@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Many xxxof_member() macros make use of the same construction
to refer to a member of a struct
without needing a variable of the struct type.

memberof(T, m)
simplifies all of those,
avoids possible mistakes in repetition,
adds a meaningful name to the construction,
and improves readability by avoiding too many parentheses together.

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Corey Minyard <cminyard@mvista.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
---
 include/linux/container_of.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/container_of.h b/include/linux/container_of.h
index 2f4944b791b8..199c78a3bf29 100644
--- a/include/linux/container_of.h
+++ b/include/linux/container_of.h
@@ -5,6 +5,9 @@
 #include <linux/build_bug.h>
 #include <linux/err.h>
 
+
+#define memberof(T, m)   (((T *) NULL)->m)
+
 #define typeof_member(T, m)	typeof(((T*)0)->m)
 
 /**
-- 
2.33.1