linux-kernel - Re: [PATCH v2 01/34] drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge

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Message-ID: <20250428170045.5ca315ce@booty>
Date: Mon, 28 Apr 2025 17:00:45 +0200
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: "Andy Yan" <andyshrk@....com>
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Subject: Re: [PATCH v2 01/34] drm: convert many bridge drivers from
 devm_kzalloc() to devm_drm_bridge_alloc() API

Hallo Andy,

On Mon, 28 Apr 2025 20:44:03 +0800 (CST)
"Andy Yan" <andyshrk@....com> wrote:

> Hi ,
> 
> At 2025-04-25 02:59:08, "Luca Ceresoli" <luca.ceresoli@...tlin.com> wrote:
> >devm_drm_bridge_alloc() is the new API to be used for allocating (and
> >partially initializing) a private driver struct embedding a struct
> >drm_bridge.
> >
> >For many drivers having a simple code flow in the probe function, this
> >commit does a mass conversion automatically with the following semantic
> >patch. The changes have been reviewed manually for correctness as well as
> >to find any false positives.
> >
> >  @@
> >  type T;
> >  identifier C;
> >  identifier BR;
> >  expression DEV;
> >  expression FUNCS;
> >  @@
> >  -T *C;
> >  +T *C;
> >   ...
> >  (
> >  -C = devm_kzalloc(DEV, ...);
> >  -if (!C)
> >  -    return -ENOMEM;
> >  +C = devm_drm_bridge_alloc(DEV, T, BR, FUNCS);
> >  +if (IS_ERR(C))
> >  +     return PTR_ERR(C);
> >  |
> >  -C = devm_kzalloc(DEV, ...);
> >  -if (!C)
> >  -    return ERR_PTR(-ENOMEM);
> >  +C = devm_drm_bridge_alloc(DEV, T, BR, FUNCS);
> >  +if (IS_ERR(C))
> >  +     return PTR_ERR(C);
> >  )
> >   ...
> >  -C->BR.funcs = FUNCS;
> >
> >Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

[...]

> >diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> >index 5e5f8c2f95be1f5c4633f1093b17a00f9425bb37..9b1dfdb5e7ee528c876c01916c9821d550cad679 100644
> >--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> >+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> >@@ -1045,9 +1045,10 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
> > 		return ERR_PTR(-ENODEV);
> > 	}
> > 
> >-	hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
> >-	if (!hdmi)
> >-		return ERR_PTR(-ENOMEM);
> >+	hdmi = devm_drm_bridge_alloc(dev, struct dw_hdmi_qp, bridge,
> >+				     &dw_hdmi_qp_bridge_funcs);
> >+	if (IS_ERR(hdmi))
> >+		return PTR_ERR(hdmi);  
> 
>            This should return hdmi or ERR_CAST(hdmi);

Indeed, thanks!

My coccinelle patch is clearly not clever enough. I'll see whether I
can fix it, otherwise I'll handle these 3 special cases manually, along
with another similar one (imx/imx-legacy-bridge.c) I just spotted after
your report.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com