nfp: preallocate RX buffers early in .ndo_open

We want the .ndo_open() to have following structure:
 - allocate resources;
 - configure HW/FW;
 - enable the device from stack perspective.
Therefore filling RX rings needs to be moved to the beginning
of .ndo_open().
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1666,28 +1666,19 @@ static void nfp_net_clear_config_and_disable(struct nfp_net *nn)
  * @nn:      NFP Net device structure
  * @r_vec:   Ring vector to be started
  */
-static int nfp_net_start_vec(struct nfp_net *nn, struct nfp_net_r_vector *r_vec)
+static void
+nfp_net_start_vec(struct nfp_net *nn, struct nfp_net_r_vector *r_vec)
 {
 	unsigned int irq_vec;
-	int err = 0;
 
 	irq_vec = nn->irq_entries[r_vec->irq_idx].vector;
 
 	disable_irq(irq_vec);
 
-	err = nfp_net_rx_ring_bufs_alloc(r_vec->nfp_net, r_vec->rx_ring);
-	if (err) {
-		nn_err(nn, "RV%02d: couldn't allocate enough buffers\n",
-		       r_vec->irq_idx);
-		goto out;
-	}
 	nfp_net_rx_ring_fill_freelist(r_vec->rx_ring);
-
 	napi_enable(&r_vec->napi);
-out:
-	enable_irq(irq_vec);
 
-	return err;
+	enable_irq(irq_vec);
 }
 
 static int nfp_net_netdev_open(struct net_device *netdev)
@@ -1742,6 +1733,10 @@ static int nfp_net_netdev_open(struct net_device *netdev)
 		err = nfp_net_rx_ring_alloc(nn->r_vecs[r].rx_ring);
 		if (err)
 			goto err_free_tx_ring_p;
+
+		err = nfp_net_rx_ring_bufs_alloc(nn, nn->r_vecs[r].rx_ring);
+		if (err)
+			goto err_flush_rx_ring_p;
 	}
 
 	err = netif_set_real_num_tx_queues(netdev, nn->num_tx_rings);
@@ -1814,11 +1809,8 @@ static int nfp_net_netdev_open(struct net_device *netdev)
 	 * - enable all TX queues
 	 * - set link state
 	 */
-	for (r = 0; r < nn->num_r_vecs; r++) {
-		err = nfp_net_start_vec(nn, &nn->r_vecs[r]);
-		if (err)
-			goto err_disable_napi;
-	}
+	for (r = 0; r < nn->num_r_vecs; r++)
+		nfp_net_start_vec(nn, &nn->r_vecs[r]);
 
 	netif_tx_wake_all_queues(netdev);
 
@@ -1827,18 +1819,14 @@ static int nfp_net_netdev_open(struct net_device *netdev)
 
 	return 0;
 
-err_disable_napi:
-	while (r--) {
-		napi_disable(&nn->r_vecs[r].napi);
-		nfp_net_rx_ring_reset(nn->r_vecs[r].rx_ring);
-		nfp_net_rx_ring_bufs_free(nn, nn->r_vecs[r].rx_ring);
-	}
 err_clear_config:
 	nfp_net_clear_config_and_disable(nn);
 err_free_rings:
 	r = nn->num_r_vecs;
 err_free_prev_vecs:
 	while (r--) {
+		nfp_net_rx_ring_bufs_free(nn, nn->r_vecs[r].rx_ring);
+err_flush_rx_ring_p:
 		nfp_net_rx_ring_free(nn->r_vecs[r].rx_ring);
 err_free_tx_ring_p:
 		nfp_net_tx_ring_free(nn->r_vecs[r].tx_ring);