linux-kernel - Re: [PATCH] drm/stm: ltdc: fix warning in ltdc_crtc_update

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Message-ID: <f5b79561-0084-96f9-6986-0f17c11f0143@st.com>
Date:   Mon, 16 Apr 2018 09:18:49 +0000
From:   Yannick FERTRE <yannick.fertre@...com>
To:     Philippe CORNU <philippe.cornu@...com>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Vincent ABRIOU <vincent.abriou@...com>,
        "Dan Carpenter" <dan.carpenter@...cle.com>,
        David Airlie <airlied@...ux.ie>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Alexandre TORGUE <alexandre.torgue@...com>
Subject: Re: [PATCH] drm/stm: ltdc: fix warning in ltdc_crtc_update_clut()

Reviewed-by: yannick fertre <yannick.fertre@...com>


On 04/10/2018 03:53 PM, Philippe Cornu wrote:
> Fix the warning
> "warn: variable dereferenced before check 'crtc' (see line 390)"
> by removing unnecessary checks as ltdc_crtc_update_clut() is
> only called from ltdc_crtc_atomic_flush() where crtc and
> crtc->state are not NULL.
>
> Many thanks to Dan Carpenter for the bug report
> https://lists.freedesktop.org/archives/dri-devel/2018-February/166918.html
>
> Signed-off-by: Philippe Cornu <philippe.cornu@...com>
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> ---
>   drivers/gpu/drm/stm/ltdc.c | 3 ---
>   1 file changed, 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 061d2b6e5157..e3121d9e4230 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -392,9 +392,6 @@ static void ltdc_crtc_update_clut(struct drm_crtc *crtc)
>   	u32 val;
>   	int i;
>   
> -	if (!crtc || !crtc->state)
> -		return;
> -
>   	if (!crtc->state->color_mgmt_changed || !crtc->state->gamma_lut)
>   		return;
>