linux-kernel - Re: [PATCH v2 38/59] drm-print: fix config-dependent unused variable

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Message-ID: <04b28c61-6930-48aa-8775-471311e57486@bootlin.com>
Date: Mon, 24 Mar 2025 16:23:29 +0100
From: Louis Chauvet <louis.chauvet@...tlin.com>
To: Jim Cromie <jim.cromie@...il.com>, linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
 intel-gvt-dev@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
 intel-gfx-trybot@...ts.freedesktop.org
Cc: jbaron@...mai.com, gregkh@...uxfoundation.org, ukaszb@...omium.org,
 daniel.vetter@...ll.ch, tvrtko.ursulin@...ux.intel.com,
 jani.nikula@...el.com, ville.syrjala@...ux.intel.com
Subject: Re: [PATCH v2 38/59] drm-print: fix config-dependent unused variable



Le 20/03/2025 à 19:52, Jim Cromie a écrit :
> With CONFIG_DRM_USE_DYNAMIC_DEBUG=y, __drm_printfn_dbg() gets an
> unused variable warning/error on 'category', even though the usage
> follows immediately, in drm_debug_enabled(category).
> 
> For static-key optimized dyndbg, the macro doesn't actually check the
> category var, since the static-key patches in the proper state.  The
> compiler evidently sees this lack of reference and complains.
> 
> So this drops the local var and refs the field directly in the
> macro-call, which avoids the warning/error.
> 
> Signed-off-by: Jim Cromie <jim.cromie@...il.com>

Reviewed-by: Louis Chauvet <louis.chauvet@...tlin.com>

I believe I can merge it before the entire series. Does anyone have any 
objections?

> ---
>   drivers/gpu/drm/drm_print.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index 46d53fe30204..41ad11247b48 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -212,9 +212,8 @@ void __drm_printfn_dbg(struct drm_printer *p, struct va_format *vaf)
>   {
>   	const struct drm_device *drm = p->arg;
>   	const struct device *dev = drm ? drm->dev : NULL;
> -	enum drm_debug_category category = p->category;
>   
> -	if (!__drm_debug_enabled(category))
> +	if (!__drm_debug_enabled(p->category))
>   		return;
>   
>   	__drm_dev_vprintk(dev, KERN_DEBUG, p->origin, p->prefix, vaf);

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com