drm/vkms: fix variable dereferenced before check warning

Smatch warns:

drivers/gpu/drm/vkms/vkms_plane.c:110 vkms_plane_atomic_update() warn:
 variable dereferenced before check 'fb' (see line 108)

Fix the warning by moving the dereference after the NULL check.

Fixes: 8ba1648567e2 ("drm: vkms: Refactor the plane composer to accept new formats")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908105623.72777-1-harshit.m.mogalapalli@oracle.com

diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index f4319066adcc9c340f4bac51323e935d8389bdf2..c3a845220e10c4d8d9a37b08e6722e6bfb514da2 100644 (file)
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -105,11 +105,12 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
        struct drm_shadow_plane_state *shadow_plane_state;
        struct drm_framebuffer *fb = new_state->fb;
        struct vkms_frame_info *frame_info;
-       u32 fmt = fb->format->format;
+       u32 fmt;
 
        if (!new_state->crtc || !fb)
                return;
 
+       fmt = fb->format->format;
        vkms_plane_state = to_vkms_plane_state(new_state);
        shadow_plane_state = &vkms_plane_state->base;