Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20200211210618.GA29823@embeddedor>
In-Reply-To: <20200211210618.GA29823@embeddedor>
From:   Bartosz Golaszewski <bgolaszewski@baylibre.com>
Date:   Mon, 17 Feb 2020 10:38:43 +0100
Message-ID: <CAMpxmJUDG6xq2qUq6yDRQQjbZGsjTTbDUCN8hGkiQwGZk=z05A@mail.gmail.com>
Subject: Re: [PATCH] gpio: uniphier: Replace zero-length array with
 flexible-array member
To:     "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        linux-gpio <linux-gpio@vger.kernel.org>,
        arm-soc <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

wt., 11 lut 2020 o 22:03 Gustavo A. R. Silva <gustavo@embeddedor.com>
napisa=C5=82(a):
>
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2]=
,
> introduced in C99:
>
> struct foo {
>         int stuff;
>         struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertenly introduced[3] to the codebase from now on.
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Patch applied, thanks!

Bartosz