drm/msm: Removed unused struct_mutex_task

Recent changes to locking have rendered struct_mutex_task
unused.

Unused since 0e08270a1f01.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.h

@@ -154,12 +154,6 @@ struct msm_drm_private {
 	struct shrinker shrinker;
 
 	struct msm_vblank_ctrl vblank_ctrl;
-
-	/* task holding struct_mutex.. currently only used in submit path
-	 * to detect and reject faults from copy_from_user() for submit
-	 * ioctl.
-	 */
-	struct task_struct *struct_mutex_task;
 };
 
 struct msm_format {

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -463,7 +463,6 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 			goto out_unlock;
 		}
 	}
-	priv->struct_mutex_task = current;
 
 	submit = submit_create(dev, gpu, queue, args->nr_bos, args->nr_cmds);
 	if (!submit) {
@@ -581,7 +580,6 @@ out:
 out_unlock:
 	if (ret && (out_fence_fd >= 0))
 		put_unused_fd(out_fence_fd);
-	priv->struct_mutex_task = NULL;
 	mutex_unlock(&dev->struct_mutex);
 	return ret;
 }