drm/xe/bo: Gracefully handle errors from ttm_bo_move_accel_cleanup().

The function ttm_bo_move_accel_cleanup() attempts to help pipeline a
move, and in doing so, needs memory allocations which may fail.

Rather than failing in a state where the new resource may freed while
accessed by the copy engine, sync uninterruptible and do a failsafe
cleanup.

v2:
- Don't try to attach the signaled fence on ttm_bo_move_accel_cleanup()
  error.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230626181741.32820-4-thomas.hellstrom@linux.intel.comSigned-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_bo.c

@@ -700,6 +700,11 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
 		if (!move_lacks_source) {
 			ret = ttm_bo_move_accel_cleanup(ttm_bo, fence, evict,
 							true, new_mem);
+			if (ret) {
+				dma_fence_wait(fence, false);
+				ttm_bo_move_null(ttm_bo, new_mem);
+				ret = 0;
+			}
 		} else {
 			/*
 			 * ttm_bo_move_accel_cleanup() may blow up if