linux-kernel - Re: [PATCH] drm/gma500/oaktrail_lvds: replace continue with break

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Date:   Sat, 19 Jun 2021 16:40:25 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Patrik Jakobsson <patrik.r.jakobsson@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/gma500/oaktrail_lvds: replace continue with break

On Fri, Jun 18, 2021 at 07:35:24PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> Currently a loop scans through the connector list checking
> for connectors that do not match a specific criteria. The
> use of the continue statement is a little unintuitive and
> can confuse static analysis checking.  Invert the criteria
> matching logic and use a break to terminate the loop once
> the first suitable connector has been found.
> 
> Thanks to Patrik Jakobsson for explaining the original
> intent of the code and suggesting this change.
> 
> Addresses-Coverity: ("Continue has no effect")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/gpu/drm/gma500/oaktrail_lvds.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/gma500/oaktrail_lvds.c b/drivers/gpu/drm/gma500/oaktrail_lvds.c
> index 432bdcc57ac9..8541dcf237eb 100644
> --- a/drivers/gpu/drm/gma500/oaktrail_lvds.c
> +++ b/drivers/gpu/drm/gma500/oaktrail_lvds.c
> @@ -113,8 +113,8 @@ static void oaktrail_lvds_mode_set(struct drm_encoder *encoder,
>  
>  	/* Find the connector we're trying to set up */
>  	list_for_each_entry(connector, &mode_config->connector_list, head) {
> -		if (!connector->encoder || connector->encoder->crtc != crtc)
> -			continue;
> +		if (connector->encoder && connector->encoder->crtc == crtc)
> +			break;
>  	}
>  
>  	if (!connector) {

This test is wrong/impossible.  It should be:

	if (list_entry_is_head(connector, &mode_config->connector_list,
			       head)) {

regards,
dan carpenter