drm/nouveau/debugfs: Move a variable assignment behind a null pointer check in...

drm/nouveau/debugfs: Move a variable assignment behind a null pointer check in nouveau_debugfs_pstate_get()

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “nouveau_debugfs_pstate_get”.

Thus avoid the risk for undefined behaviour by moving the assignment
for the variable “ctrl” behind the null pointer check.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5b7b99f7-1692-74e5-4b1e-cfa14dad7c57@web.de

drivers/gpu/drm/nouveau/nouveau_debugfs.c

@@ -73,13 +73,14 @@ nouveau_debugfs_pstate_get(struct seq_file *m, void *data)
 {
 	struct drm_device *drm = m->private;
 	struct nouveau_debugfs *debugfs = nouveau_debugfs(drm);
-	struct nvif_object *ctrl = &debugfs->ctrl;
+	struct nvif_object *ctrl;
 	struct nvif_control_pstate_info_v0 info = {};
 	int ret, i;
 
 	if (!debugfs)
 		return -ENODEV;
 
+	ctrl = &debugfs->ctrl;
 	ret = nvif_mthd(ctrl, NVIF_CONTROL_PSTATE_INFO, &info, sizeof(info));
 	if (ret)
 		return ret;