linux-kernel - Re: [PATCH] drm/vc4: clean up error handling on devm

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Message-ID: <20170908133949.ekrgphd6dm4ctiih@imgtec.com>
Date:   Fri, 8 Sep 2017 14:39:49 +0100
From:   Eric Engestrom <eric.engestrom@...tec.com>
To:     Colin King <colin.king@...onical.com>
CC:     Eric Anholt <eric@...olt.net>, David Airlie <airlied@...ux.ie>,
        <dri-devel@...ts.freedesktop.org>,
        <kernel-janitors@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/vc4: clean up error handling on devm_kzalloc failure

On Friday, 2017-09-08 14:17:04 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The current error handling on devm_kzalloc failures performs a non-null
> check on connector. Thss check is redundant because connector is null
> at that failure point.  With this check removed, we may as well make
> the failure path into a trivial -ENOMEM return to clean up the error
> handling.
> 
> Detected by CoverityScan CID#1339527 ("Logically dead code")
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/gpu/drm/vc4/vc4_hdmi.c | 13 ++-----------
>  1 file changed, 2 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 937da8dd65b8..a8808c1a1e03 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -311,14 +311,11 @@ static struct drm_connector *vc4_hdmi_connector_init(struct drm_device *dev,
>  {
>  	struct drm_connector *connector = NULL;

This `= NULL` isn't needed anymore either.

Reviewed-by: Eric Engestrom <eric.engestrom@...tec.com>

>  	struct vc4_hdmi_connector *hdmi_connector;
> -	int ret = 0;
>  
>  	hdmi_connector = devm_kzalloc(dev->dev, sizeof(*hdmi_connector),
>  				      GFP_KERNEL);
> -	if (!hdmi_connector) {
> -		ret = -ENOMEM;
> -		goto fail;
> -	}
> +	if (!hdmi_connector)
> +		return ERR_PTR(-ENOMEM);
>  	connector = &hdmi_connector->base;
>  
>  	hdmi_connector->encoder = encoder;
> @@ -336,12 +333,6 @@ static struct drm_connector *vc4_hdmi_connector_init(struct drm_device *dev,
>  	drm_mode_connector_attach_encoder(connector, encoder);
>  
>  	return connector;
> -
> - fail:
> -	if (connector)
> -		vc4_hdmi_connector_destroy(connector);
> -
> -	return ERR_PTR(ret);
>  }
>  
>  static void vc4_hdmi_encoder_destroy(struct drm_encoder *encoder)
> -- 
> 2.14.1
>