drm/ttm: alter cpu_writers to return -EBUSY in ttm_execbuf_util reservations

This is similar to other platforms that don't allow command submission
to buffers locked on the cpu.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index b227a9961a07..1986d006c264 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -185,10 +185,7 @@ retry_this_bo:
                         ttm_eu_backoff_reservation_locked(list);
                         spin_unlock(&glob->lru_lock);
                         ttm_eu_list_ref_sub(list);
-                        ret = ttm_bo_wait_cpu(bo, false);
-                        if (ret)
-                                return ret;
-                        goto retry;
+                        return -EBUSY;
                 }
         }