Re: [PATCH] amba: tegra-ahb: Replace zero-length array with flexible-array member

From: Gustavo A. R. Silva
Date: Thu Feb 27 2020 - 14:30:58 EST


Hi all,

Friendly ping: Who can take this?

Thanks
--
Gustavo

On 2/11/20 15:02, Gustavo A. R. Silva wrote:
> 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.
>
> [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@xxxxxxxxxxxxxx>
> ---
> drivers/amba/tegra-ahb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/amba/tegra-ahb.c b/drivers/amba/tegra-ahb.c
> index b0b688c481e8..e9e5c7bb580c 100644
> --- a/drivers/amba/tegra-ahb.c
> +++ b/drivers/amba/tegra-ahb.c
> @@ -129,7 +129,7 @@ static const u32 tegra_ahb_gizmo[] = {
> struct tegra_ahb {
> void __iomem *regs;
> struct device *dev;
> - u32 ctx[0];
> + u32 ctx[];
> };
>
> static inline u32 gizmo_readl(struct tegra_ahb *ahb, u32 offset)
>