linux-kernel - Re: [PATCH][next] drm/omap: clean up error exit path on omap

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Message-ID: <3ecf364c-8bb1-4f96-817e-fd36a2c29c84@ideasonboard.com>
Date: Mon, 28 Oct 2024 10:28:06 +0200
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Colin Ian King <colin.i.king@...il.com>
Cc: kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH][next] drm/omap: clean up error exit path on omap_encoder
 allocation failure

Hi,

On 15/10/2024 17:10, Colin Ian King wrote:
> Currently when an allocation failure occurs for omap_encoder the exit
> path will destroy encoder via omap_encoder_destroy  if it is not null.
> However, encoder is always null at this point, so the check and destroy
> is redundant and can be removed. Clean up the code by removing the exit
> path and redundant omap_encoder_destroy call, and just return NULL.
> 
> Signed-off-by: Colin Ian King <colin.i.king@...il.com>
> ---
>   drivers/gpu/drm/omapdrm/omap_encoder.c | 8 +-------
>   1 file changed, 1 insertion(+), 7 deletions(-)

This is correct, but I think it would make sense to fix the error 
handling in omap_encoder_init() fully, instead of just partially: 
drm_encoder_init() can return an error, in which case we should free the 
omap_encoder.

Could you update the patch to do that too?

  Tomi

> diff --git a/drivers/gpu/drm/omapdrm/omap_encoder.c b/drivers/gpu/drm/omapdrm/omap_encoder.c
> index 4dd05bc732da..a99022638a2c 100644
> --- a/drivers/gpu/drm/omapdrm/omap_encoder.c
> +++ b/drivers/gpu/drm/omapdrm/omap_encoder.c
> @@ -126,21 +126,15 @@ struct drm_encoder *omap_encoder_init(struct drm_device *dev,
>   
>   	omap_encoder = kzalloc(sizeof(*omap_encoder), GFP_KERNEL);
>   	if (!omap_encoder)
> -		goto fail;
> +		return NULL;
>   
>   	omap_encoder->output = output;
>   
>   	encoder = &omap_encoder->base;
>   
>   	drm_encoder_init(dev, encoder, &omap_encoder_funcs,
>   			 DRM_MODE_ENCODER_TMDS, NULL);
>   	drm_encoder_helper_add(encoder, &omap_encoder_helper_funcs);
>   
>   	return encoder;
> -
> -fail:
> -	if (encoder)
> -		omap_encoder_destroy(encoder);
> -
> -	return NULL;
>   }