Re: [PATCH v2 09/10] samples/kdbus: fix operator precedence issue in KDBUS_ITEM_NEXT macro

From: David Herrmann
Date: Wed Jun 10 2015 - 10:10:00 EST


Hi

On Tue, Jun 9, 2015 at 11:00 PM, Sergei Zviagintsev <sergei@xxxxxxxx> wrote:
> `item' argument in KDBUS_ITEM_NEXT macro is not enclosed into
> parentheses when the cast operator is applied, which leads to improper
> type conversion if `item' is supplied as a complex expression, e.g.
>
> KDBUS_ITEM_NEXT(condition ? a : b)
>
> Use parentheses properly to guarantee right precedence.
>
> Signed-off-by: Sergei Zviagintsev <sergei@xxxxxxxx>
> ---
> samples/kdbus/kdbus-api.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx>

Thanks
David

> diff --git a/samples/kdbus/kdbus-api.h b/samples/kdbus/kdbus-api.h
> index 2de4d6a8c51e..fab873b89d97 100644
> --- a/samples/kdbus/kdbus-api.h
> +++ b/samples/kdbus/kdbus-api.h
> @@ -8,7 +8,7 @@
> #define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data)
> #define KDBUS_ITEM_SIZE(s) KDBUS_ALIGN8((s) + KDBUS_ITEM_HEADER_SIZE)
> #define KDBUS_ITEM_NEXT(item) \
> - (typeof(item))(((uint8_t *)item) + KDBUS_ALIGN8((item)->size))
> + (typeof(item))((uint8_t *)(item) + KDBUS_ALIGN8((item)->size))
> #define KDBUS_FOREACH(iter, first, _size) \
> for (iter = (first); \
> ((uint8_t *)(iter) < (uint8_t *)(first) + (_size)) && \
> --
> 1.8.3.1
>
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