drm/drm_crtc: return -EFAULT on copy_to_user errors

copy_from_user() returns the number of bytes left to be copied but we
want to return a negative error code here.  This is in the ioctl handler
so the error code get returned to userspace.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 994d23beeb1d..57cea01c4ffb 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1840,8 +1840,10 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 
                 ret = copy_from_user(clips, clips_ptr,
                                      num_clips * sizeof(*clips));
-                if (ret)
+                if (ret) {
+                        ret = -EFAULT;
                         goto out_err2;
+                }
         }
 
         if (fb->funcs->dirty) {