IB/mlx5: Fix MR re-registration flow to use UMR properly

The UMR WQE in the MR re-registration flow requires that
modify_atomic and modify_entity_size capabilities are enabled.
Therefore, check that the these capabilities are present before going to
umr flow and go through slow path if not.

Fixes: c8d75a98 ("IB/mlx5: Respect new UMR capabilities")
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Guy Levi <guyle@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20190815083834.9245-8-leon@kernel.orgSigned-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/mr.c

@@ -1446,7 +1446,8 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start,
 			goto err;
 	}
 
-	if (flags & IB_MR_REREG_TRANS && !use_umr_mtt_update(mr, addr, len)) {
+	if (!mlx5_ib_can_use_umr(dev, true) ||
+	    (flags & IB_MR_REREG_TRANS && !use_umr_mtt_update(mr, addr, len))) {
 		/*
 		 * UMR can't be used - MKey needs to be replaced.
 		 */