[PATCH iwl-next v2 2/4] igb: Link queues to NAPI instances

Kurt Kanzenbach
2025-02-17T11:31:32Z

Link queues to NAPI instances via netdev-genl API. This is required to use
XDP/ZC busy polling. See commit 5ef44b3cb43b ("xsk: Bring back busy polling
support") for details.

This also allows users to query the info with netlink:

|$ ./tools/net/ynl/pyynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
| --dump queue-get --json='{"ifindex": 2}'
|[{'id': 0, 'ifindex': 2, 'napi-id': 8201, 'type': 'rx'},
| {'id': 1, 'ifindex': 2, 'napi-id': 8202, 'type': 'rx'},
| {'id': 2, 'ifindex': 2, 'napi-id': 8203, 'type': 'rx'},
| {'id': 3, 'ifindex': 2, 'napi-id': 8204, 'type': 'rx'},
| {'id': 0, 'ifindex': 2, 'napi-id': 8201, 'type': 'tx'},
| {'id': 1, 'ifindex': 2, 'napi-id': 8202, 'type': 'tx'},
| {'id': 2, 'ifindex': 2, 'napi-id': 8203, 'type': 'tx'},
| {'id': 3, 'ifindex': 2, 'napi-id': 8204, 'type': 'tx'}]

Add rtnl locking to PCI error handlers, because netif_queue_set_napi()
requires the lock held.

While at __igb_open() use RCT coding style.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
drivers/net/ethernet/intel/igb/igb.h | 2 ++
drivers/net/ethernet/intel/igb/igb_main.c | 43 +++++++++++++++++++++++++++----
drivers/net/ethernet/intel/igb/igb_xsk.c | 2 ++
3 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 02f340280d20a6f7e32bbd3dfcbb9c1c7b4c6662..79eca385a751bfdafdf384928b6cc1b350b22560 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -722,6 +722,8 @@ enum igb_boards {

extern char igb_driver_name[];

+void igb_set_queue_napi(struct igb_adapter *adapter, int q_idx,
+ struct napi_struct *napi);
int igb_xmit_xdp_ring(struct igb_adapter *adapter,
struct igb_ring *ring,
struct xdp_frame *xdpf);
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index d4128d19cc08f62f95682069bb5ed9b8bbbf10cb..6870803a42455aa1d31f39beb027cf282064388f 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2099,6 +2099,22 @@ static void igb_check_swap_media(struct igb_adapter *adapter)
wr32(E1000_CTRL_EXT, ctrl_ext);
}

+void igb_set_queue_napi(struct igb_adapter *adapter, int vector,
+ struct napi_struct *napi)
+{
+ struct igb_q_vector *q_vector = adapter->q_vector[vector];
+
+ if (q_vector->rx.ring)
+ netif_queue_set_napi(adapter->netdev,
+ q_vector->rx.ring->queue_index,
+ NETDEV_QUEUE_TYPE_RX, napi);
+
+ if (q_vector->tx.ring)
+ netif_queue_set_napi(adapter->netdev,
+ q_vector->tx.ring->queue_index,
+ NETDEV_QUEUE_TYPE_TX, napi);
+}
+
/**
* igb_up - Open the interface and prepare it to handle traffic
* @adapter: board private structure
@@ -2106,6 +2122,7 @@ static void igb_check_swap_media(struct igb_adapter *adapter)
int igb_up(struct igb_adapter *adapter)
{
struct e1000_hw *hw = &adapter->hw;
+ struct napi_struct *napi;
int i;

/* hardware has been reset, we need to reload some things */
@@ -2113,8 +2130,11 @@ int igb_up(struct igb_adapter *adapter)

clear_bit(__IGB_DOWN, &adapter->state);

- for (i = 0; i < adapter->num_q_vectors; i++)
- napi_enable(&(adapter->q_vector[i]->napi));
+ for (i = 0; i < adapter->num_q_vectors; i++) {
+ napi = &adapter->q_vector[i]->napi;
+ napi_enable(napi);
+ igb_set_queue_napi(adapter, i, napi);
+ }

if (adapter->flags & IGB_FLAG_HAS_MSIX)
igb_configure_msix(adapter);
@@ -2184,6 +2204,7 @@ void igb_down(struct igb_adapter *adapter)
for (i = 0; i < adapter->num_q_vectors; i++) {
if (adapter->q_vector[i]) {
napi_synchronize(&adapter->q_vector[i]->napi);
+ igb_set_queue_napi(adapter, i, NULL);
napi_disable(&adapter->q_vector[i]->napi);
}
}
@@ -4116,8 +4137,9 @@ static int igb_sw_init(struct igb_adapter *adapter)
static int __igb_open(struct net_device *netdev, bool resuming)
{
struct igb_adapter *adapter = netdev_priv(netdev);
- struct e1000_hw *hw = &adapter->hw;
struct pci_dev *pdev = adapter->pdev;
+ struct e1000_hw *hw = &adapter->hw;
+ struct napi_struct *napi;
int err;
int i;

@@ -4169,8 +4191,11 @@ static int __igb_open(struct net_device *netdev, bool resuming)
/* From here on the code is the same as igb_up() */
clear_bit(__IGB_DOWN, &adapter->state);

- for (i = 0; i < adapter->num_q_vectors; i++)
- napi_enable(&(adapter->q_vector[i]->napi));
+ for (i = 0; i < adapter->num_q_vectors; i++) {
+ napi = &adapter->q_vector[i]->napi;
+ napi_enable(napi);
+ igb_set_queue_napi(adapter, i, napi);
+ }

/* Clear any pending interrupts. */
rd32(E1000_TSICR);
@@ -9677,8 +9702,11 @@ static pci_ers_result_t igb_io_error_detected(struct pci_dev *pdev,
if (state == pci_channel_io_perm_failure)
return PCI_ERS_RESULT_DISCONNECT;

+ rtnl_lock();
if (netif_running(netdev))
igb_down(adapter);
+ rtnl_unlock();
+
pci_disable_device(pdev);

/* Request a slot reset. */
@@ -9737,16 +9765,21 @@ static void igb_io_resume(struct pci_dev *pdev)
struct net_device *netdev = pci_get_drvdata(pdev);
struct igb_adapter *adapter = netdev_priv(netdev);

+ rtnl_lock();
if (netif_running(netdev)) {
if (!test_bit(__IGB_DOWN, &adapter->state)) {
dev_dbg(&pdev->dev, "Resuming from non-fatal error, do nothing.\n");
+ rtnl_unlock();
return;
}
+
if (igb_up(adapter)) {
dev_err(&pdev->dev, "igb_up failed after reset\n");
+ rtnl_unlock();
return;
}
}
+ rtnl_unlock();

netif_device_attach(netdev);

diff --git a/drivers/net/ethernet/intel/igb/igb_xsk.c b/drivers/net/ethernet/intel/igb/igb_xsk.c
index 157d43787fa0b55a74714f69e9e7903b695fcf0a..a5ad090dfe94b6afc8194fe39d28cdd51c7067b0 100644
--- a/drivers/net/ethernet/intel/igb/igb_xsk.c
+++ b/drivers/net/ethernet/intel/igb/igb_xsk.c
@@ -45,6 +45,7 @@ static void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid)
synchronize_net();

/* Rx/Tx share the same napi context. */
+ igb_set_queue_napi(adapter, qid, NULL);
napi_disable(&rx_ring->q_vector->napi);

igb_clean_tx_ring(tx_ring);
@@ -78,6 +79,7 @@ static void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)

/* Rx/Tx share the same napi context. */
napi_enable(&rx_ring->q_vector->napi);
+ igb_set_queue_napi(adapter, qid, &rx_ring->q_vector->napi);
}

struct xsk_buff_pool *igb_xsk_pool(struct igb_adapter *adapter,

--
2.39.5