dpaa2-switch: seed the buffer pool after allocating the swp

Any interraction with the buffer pool (seeding a buffer, acquire one) is
made through a software portal (SWP, a DPIO object).
There are circumstances where the dpaa2-switch driver probes on a DPSW
before any DPIO devices have been probed. In this case, seeding of the
buffer pool will lead to a panic since no SWPs are initialized.

To fix this, seed the buffer pool after making sure that the software
portals have been probed and are ready to be used.

Fixes: 0b1b7137 ("staging: dpaa2-switch: handle Rx path on control interface")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c

@@ -2770,32 +2770,32 @@ static int dpaa2_switch_ctrl_if_setup(struct ethsw_core *ethsw)
 	if (err)
 		return err;
 
-	err = dpaa2_switch_seed_bp(ethsw);
-	if (err)
-		goto err_free_dpbp;
-
 	err = dpaa2_switch_alloc_rings(ethsw);
 	if (err)
-		goto err_drain_dpbp;
+		goto err_free_dpbp;
 
 	err = dpaa2_switch_setup_dpio(ethsw);
 	if (err)
 		goto err_destroy_rings;
 
+	err = dpaa2_switch_seed_bp(ethsw);
+	if (err)
+		goto err_deregister_dpio;
+
 	err = dpsw_ctrl_if_enable(ethsw->mc_io, 0, ethsw->dpsw_handle);
 	if (err) {
 		dev_err(ethsw->dev, "dpsw_ctrl_if_enable err %d\n", err);
-		goto err_deregister_dpio;
+		goto err_drain_dpbp;
 	}
 
 	return 0;
 
+err_drain_dpbp:
+	dpaa2_switch_drain_bp(ethsw);
 err_deregister_dpio:
 	dpaa2_switch_free_dpio(ethsw);
 err_destroy_rings:
 	dpaa2_switch_destroy_rings(ethsw);
-err_drain_dpbp:
-	dpaa2_switch_drain_bp(ethsw);
 err_free_dpbp:
 	dpaa2_switch_free_dpbp(ethsw);