linux-kernel - Re: [PATCH v2 04/26] drm/bridge: make of_drm_find_bridge() a wrapper of of_drm_get

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Message-ID: <a23be1b4-89ce-4db9-bb68-9a5aa248f4a0@infradead.org>
Date: Fri, 28 Nov 2025 13:50:19 -0800
From: Randy Dunlap <rdunlap@...radead.org>
To: Luca Ceresoli <luca.ceresoli@...tlin.com>,
 Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
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 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>,
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Cc: Hui Pu <Hui.Pu@...ealthcare.com>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 Louis Chauvet <louis.chauvet@...tlin.com>, dri-devel@...ts.freedesktop.org,
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Subject: Re: [PATCH v2 04/26] drm/bridge: make of_drm_find_bridge() a wrapper
 of of_drm_get_bridge()



On 11/28/25 8:50 AM, Luca Ceresoli wrote:
> of_drm_find_bridge() is identical to of_drm_get_bridge() except it does
> not increment the refcount. Rewrite it as a wrapper and put the bridge
> being returned so the behaviour is still the same.
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
> 
> ---
> 
> Changed in v2:
> - Added comment to document why we put the reference
> ---
>  drivers/gpu/drm/drm_bridge.c | 20 +++++++++-----------
>  1 file changed, 9 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 21a84715d221..9b7e3f859973 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -1467,19 +1467,17 @@ EXPORT_SYMBOL(of_drm_get_bridge);
>   */
>  struct drm_bridge *of_drm_find_bridge(struct device_node *np)
>  {
> -	struct drm_bridge *bridge;
> -
> -	mutex_lock(&bridge_lock);
> +	struct drm_bridge *bridge = of_drm_get_bridge(np);
>  
> -	list_for_each_entry(bridge, &bridge_list, list) {
> -		if (bridge->of_node == np) {
> -			mutex_unlock(&bridge_lock);
> -			return bridge;
> -		}
> -	}
> +	/**

This isn't a kernel-doc comment, so please don't use "/**" here.
Just use "/*".

> +	 * We need to emulate the original semantics of
> +	 * of_drm_find_bridge(), which was not getting any bridge
> +	 * reference. Being now based on of_drm_get_bridge() which gets a
> +	 * reference, put it before returning.
> +	 */
> +	drm_bridge_put(bridge);
>  
> -	mutex_unlock(&bridge_lock);
> -	return NULL;
> +	return bridge;
>  }
>  EXPORT_SYMBOL(of_drm_find_bridge);
>  #endif
> 

-- 
~Randy