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SubjectRe: [PATCH] drm/loongson: Remove a useless check in cursor_plane_atomic_async_check()
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Am 10.07.23 um 12:24 schrieb Sui Jingfeng:
> Because smatch warnings:
>
> drivers/gpu/drm/loongson/lsdc_plane.c:199
> lsdc_cursor_plane_atomic_async_check()
> warn: variable dereferenced before check 'state' (see line 180)
>
> vim +/state +199 drivers/gpu/drm/loongson/lsdc_plane.c
>
> 174 static int
> lsdc_cursor_plane_atomic_async_check(struct drm_plane *plane,
> 175 struct drm_atomic_state *state)
> 176 {
> 177 struct drm_plane_state *new_state;
> 178 struct drm_crtc_state *crtc_state;
> 179
> 180 new_state = drm_atomic_get_new_plane_state(state, plane);
> ^^^^^
> state is dereferenced inside this function
>
> 181
> 182 if (!plane->state || !plane->state->fb) {
> 183 drm_dbg(plane->dev, "%s: state is NULL\n", plane->name);
> 184 return -EINVAL;
> 185 }
> 186
> 187 if (new_state->crtc_w != new_state->crtc_h) {
> 188 drm_dbg(plane->dev, "unsupported cursor size: %ux%u\n",
> 189 new_state->crtc_w, new_state->crtc_h);
> 190 return -EINVAL;
> 191 }
> 192
> 193 if (new_state->crtc_w != 64 && new_state->crtc_w != 32) {
> 194 drm_dbg(plane->dev, "unsupported cursor size: %ux%u\n",
> 195 new_state->crtc_w, new_state->crtc_h);
> 196 return -EINVAL;
> 197 }
> 198
> 199 if (state) {
> ^^^^^
> Checked too late!
>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202307100423.rV7D05Uq-lkp@intel.com/
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

BTW, you're posting these patches for loongson, but that driver is not
yet in our tree?

Best regards
Thomas


> ---
> drivers/gpu/drm/loongson/lsdc_plane.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/loongson/lsdc_plane.c b/drivers/gpu/drm/loongson/lsdc_plane.c
> index 2ab3db982aa3..0d5094633222 100644
> --- a/drivers/gpu/drm/loongson/lsdc_plane.c
> +++ b/drivers/gpu/drm/loongson/lsdc_plane.c
> @@ -196,13 +196,7 @@ static int lsdc_cursor_plane_atomic_async_check(struct drm_plane *plane,
> return -EINVAL;
> }
>
> - if (state) {
> - crtc_state = drm_atomic_get_existing_crtc_state(state, new_state->crtc);
> - } else {
> - crtc_state = plane->crtc->state;
> - drm_dbg(plane->dev, "%s: atomic state is NULL\n", plane->name);
> - }
> -
> + crtc_state = drm_atomic_get_existing_crtc_state(state, new_state->crtc);
> if (!crtc_state->active)
> return -EINVAL;
>

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
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