linux-kernel - Re: [PATCH] gpio: uniphier: Replace zero-length array with flexible-array member

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Date:   Mon, 17 Feb 2020 10:38:43 +0100
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: uniphier: Replace zero-length array with
 flexible-array member

wt., 11 lut 2020 o 22:03 Gustavo A. R. Silva <gustavo@...eddedor.com>
napisał(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@...eddedor.com>

Patch applied, thanks!

Bartosz