Merge branch 'updates-to-enetc-txq-management'

Vladimir Oltean says:

====================
Updates to ENETC TXQ management

The set ensures that the number of TXQs given by enetc to the network
stack (mqprio or TX hashing) + the number of TXQs given to XDP never
exceeds the number of available TXQs.

These are the first 4 patches of series "[v5,net-next,00/17] ENETC
mqprio/taprio cleanup" from here:
https://patchwork.kernel.org/project/netdevbpf/cover/20230202003621.2679603-1-vladimir.oltean@nxp.com/

There is no change in this version compared to there. I split them off
because this contains a fix for net-next and it would be good if it
could go in quickly. I also did it to reduce the patch count of that
other series, if I need to respin it again.
====================

Link: https://lore.kernel.org/r/20230203001116.3814809-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -28,10 +28,8 @@ EXPORT_SYMBOL_GPL(enetc_port_mac_wr);
 static int enetc_num_stack_tx_queues(struct enetc_ndev_priv *priv)
 {
 	int num_tx_rings = priv->num_tx_rings;
-	int i;
 
-	for (i = 0; i < priv->num_rx_rings; i++)
-		if (priv->rx_ring[i]->xdp.prog)
+	if (priv->xdp_prog)
 		return num_tx_rings - num_possible_cpus();
 
 	return num_tx_rings;
@@ -2456,7 +2454,6 @@ int enetc_open(struct net_device *ndev)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct enetc_bdr_resource *tx_res, *rx_res;
-	int num_stack_tx_queues;
 	bool extended;
 	int err;
 
@@ -2482,16 +2479,6 @@ int enetc_open(struct net_device *ndev)
 		goto err_alloc_rx;
 	}
 
-	num_stack_tx_queues = enetc_num_stack_tx_queues(priv);
-
-	err = netif_set_real_num_tx_queues(ndev, num_stack_tx_queues);
-	if (err)
-		goto err_set_queues;
-
-	err = netif_set_real_num_rx_queues(ndev, priv->num_rx_rings);
-	if (err)
-		goto err_set_queues;
-
 	enetc_tx_onestep_tstamp_init(priv);
 	enetc_assign_tx_resources(priv, tx_res);
 	enetc_assign_rx_resources(priv, rx_res);
@@ -2500,8 +2487,6 @@ int enetc_open(struct net_device *ndev)
 
 	return 0;
 
-err_set_queues:
-	enetc_free_rx_resources(rx_res, priv->num_rx_rings);
 err_alloc_rx:
 	enetc_free_tx_resources(tx_res, priv->num_tx_rings);
 err_alloc_tx:
@@ -2576,8 +2561,11 @@ static int enetc_reconfigure(struct enetc_ndev_priv *priv, bool extended,
 	 * without reconfiguration.
 	 */
 	if (!netif_running(priv->ndev)) {
-		if (cb)
-			cb(priv, ctx);
+		if (cb) {
+			err = cb(priv, ctx);
+			if (err)
+				return err;
+		}
 
 		return 0;
 	}
@@ -2598,8 +2586,11 @@ static int enetc_reconfigure(struct enetc_ndev_priv *priv, bool extended,
 	enetc_free_rxtx_rings(priv);
 
 	/* Interface is down, run optional callback now */
-	if (cb)
-		cb(priv, ctx);
+	if (cb) {
+		err = cb(priv, ctx);
+		if (err)
+			goto out_restart;
+	}
 
 	enetc_assign_tx_resources(priv, tx_res);
 	enetc_assign_rx_resources(priv, rx_res);
@@ -2608,6 +2599,10 @@ static int enetc_reconfigure(struct enetc_ndev_priv *priv, bool extended,
 
 	return 0;
 
+out_restart:
+	enetc_setup_bdrs(priv, extended);
+	enetc_start(priv->ndev);
+	enetc_free_rx_resources(rx_res, priv->num_rx_rings);
 out_free_tx_res:
 	enetc_free_tx_resources(tx_res, priv->num_tx_rings);
 out:
@@ -2631,6 +2626,7 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 	if (!num_tc) {
 		netdev_reset_tc(ndev);
 		netif_set_real_num_tx_queues(ndev, num_stack_tx_queues);
+		priv->min_num_stack_tx_queues = num_possible_cpus();
 
 		/* Reset all ring priorities to 0 */
 		for (i = 0; i < priv->num_tx_rings; i++) {
@@ -2661,6 +2657,7 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 
 	/* Reset the number of netdev queues based on the TC count */
 	netif_set_real_num_tx_queues(ndev, num_tc);
+	priv->min_num_stack_tx_queues = num_tc;
 
 	netdev_set_num_tc(ndev, num_tc);
 
@@ -2675,9 +2672,18 @@ EXPORT_SYMBOL_GPL(enetc_setup_tc_mqprio);
 static int enetc_reconfigure_xdp_cb(struct enetc_ndev_priv *priv, void *ctx)
 {
 	struct bpf_prog *old_prog, *prog = ctx;
-	int i;
+	int num_stack_tx_queues;
+	int err, i;
 
 	old_prog = xchg(&priv->xdp_prog, prog);
+
+	num_stack_tx_queues = enetc_num_stack_tx_queues(priv);
+	err = netif_set_real_num_tx_queues(priv->ndev, num_stack_tx_queues);
+	if (err) {
+		xchg(&priv->xdp_prog, old_prog);
+		return err;
+	}
+
 	if (old_prog)
 		bpf_prog_put(old_prog);
 
@@ -2698,9 +2704,20 @@ static int enetc_reconfigure_xdp_cb(struct enetc_ndev_priv *priv, void *ctx)
 static int enetc_setup_xdp_prog(struct net_device *ndev, struct bpf_prog *prog,
 				struct netlink_ext_ack *extack)
 {
+	int num_xdp_tx_queues = prog ? num_possible_cpus() : 0;
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	bool extended;
 
+	if (priv->min_num_stack_tx_queues + num_xdp_tx_queues >
+	    priv->num_tx_rings) {
+		NL_SET_ERR_MSG_FMT_MOD(extack,
+				       "Reserving %d XDP TXQs does not leave a minimum of %d TXQs for network stack (total %d available)",
+				       num_xdp_tx_queues,
+				       priv->min_num_stack_tx_queues,
+				       priv->num_tx_rings);
+		return -EBUSY;
+	}
+
 	extended = !!(priv->active_offloads & ENETC_F_RX_TSTAMP);
 
 	/* The buffer layout is changing, so we need to drain the old
@@ -2898,6 +2915,7 @@ EXPORT_SYMBOL_GPL(enetc_ioctl);
 int enetc_alloc_msix(struct enetc_ndev_priv *priv)
 {
 	struct pci_dev *pdev = priv->si->pdev;
+	int num_stack_tx_queues;
 	int first_xdp_tx_ring;
 	int i, n, err, nvec;
 	int v_tx_rings;
@@ -2974,6 +2992,17 @@ int enetc_alloc_msix(struct enetc_ndev_priv *priv)
 		}
 	}
 
+	num_stack_tx_queues = enetc_num_stack_tx_queues(priv);
+
+	err = netif_set_real_num_tx_queues(priv->ndev, num_stack_tx_queues);
+	if (err)
+		goto fail;
+
+	err = netif_set_real_num_rx_queues(priv->ndev, priv->num_rx_rings);
+	if (err)
+		goto fail;
+
+	priv->min_num_stack_tx_queues = num_possible_cpus();
 	first_xdp_tx_ring = priv->num_tx_rings - num_possible_cpus();
 	priv->xdp_tx_ring = &priv->tx_ring[first_xdp_tx_ring];
 

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -369,6 +369,9 @@ struct enetc_ndev_priv {
 
 	struct psfp_cap psfp_cap;
 
+	/* Minimum number of TX queues required by the network stack */
+	unsigned int min_num_stack_tx_queues;
+
 	struct phylink *phylink;
 	int ic_mode;
 	u32 tx_ictt;