Re: [PATCH] drm/loongson: Remove a useless check in cursor_plane_atomic_async_check()

[Thomas Zimmermann]

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.carpen...@linaro.org>
Closes: https://lore.kernel.org/r/202307100423.rv7d05uq-...@intel.com/
Signed-off-by: Sui Jingfeng <suijingf...@loongson.cn>

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



Best regards
Thomas

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

---
  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;
        }

-               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;

- if (state) {

--
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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