net: enetc: recalculate num_real_tx_queues when XDP program attaches

Since the blamed net-next commit, enetc_setup_xdp_prog() no longer goes
through enetc_open(), and therefore, the function which was supposed to
detect whether a BPF program exists (in order to crop some TX queues
from network stack usage), enetc_num_stack_tx_queues(), no longer gets
called.

We can move the netif_set_real_num_rx_queues() call to enetc_alloc_msix()
(probe time), since it is a runtime invariant. We can do the same thing
with netif_set_real_num_tx_queues(), and let enetc_reconfigure_xdp_cb()
explicitly recalculate and change the number of stack TX queues.

Fixes: c33bfaf91c4c ("net: enetc: set up XDP program under enetc_reconfigure()")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 5d7eeb1b5a23b204361024d4e0e881387b53d5fd..e18a6c834eb43dd16a362b81040cedc44043a165 100644 (file)
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -2454,7 +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;
 
@@ -2480,16 +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);
@@ -2498,8 +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:
@@ -2683,9 +2670,18 @@ 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);
 
@@ -2906,6 +2902,7 @@ 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;
@@ -2982,6 +2979,16 @@ 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;
+
        first_xdp_tx_ring = priv->num_tx_rings - num_possible_cpus();
        priv->xdp_tx_ring = &priv->tx_ring[first_xdp_tx_ring];