Re: [PATCH] include: linux/iopoll.h: silence warning when timeout_us contains *

[Sascha Hauer <sha@pengutronix.de>]

On Mon, Jan 09, 2023 at 05:00:57PM +0100, Ahmad Fatoum wrote:
> We evaluate timeout_us for truthiness to determine whether we are
> entering an infinite poll loop. When timeout_us contains a
> multiplication, GCC will warn about it and suggest replacing the *
> with &&. Silence this warning by comparing directly against 0.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  include/linux/iopoll.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
> index 8bf912e173b3..b8c55583f97f 100644
> --- a/include/linux/iopoll.h
> +++ b/include/linux/iopoll.h
> @@ -32,13 +32,13 @@
>  #define read_poll_timeout(op, val, cond, timeout_us, args...)	\
>  ({ \
>  	uint64_t start; \
> -	if (!IN_PBL && timeout_us) \
> +	if (!IN_PBL && timeout_us != 0) \

You should rather put timeout_us in brackets.

Sascha

>  		start = get_time_ns(); \
>  	for (;;) { \
>  		(val) = op(args); \
>  		if (cond) \
>  			break; \
> -		if (!IN_PBL && timeout_us && \
> +		if (!IN_PBL && timeout_us != 0 && \
>  		    is_timeout(start, ((timeout_us) * USECOND))) { \
>  			(val) = op(args); \
>  			break; \
> -- 
> 2.30.2
> 
> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |