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From: Joe Damato <jdamato@fastly.com>
To: linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org,
	intel-wired-lan@lists.osuosl.org
Cc: sridhar.samudrala@intel.com,
	amritha.nambiar@intel.com,
	nalramli@fastly.com,
	Joe Damato <jdamato@fastly.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Subject: [intel-next 1/2] net/i40e: link NAPI instances to queues and IRQs
Date: Wed, 10 Apr 2024 04:39:34 +0000
Message-Id: <20240410043936.206169-2-jdamato@fastly.com>
In-Reply-To: <20240410043936.206169-1-jdamato@fastly.com>
References: <20240410043936.206169-1-jdamato@fastly.com>
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Make i40e compatible with the newly added netlink queue GET APIs.

$ ./cli.py --spec ../../../Documentation/netlink/specs/netdev.yaml \
  --do queue-get --json '{"ifindex": 3, "id": 1, "type": "rx"}'

{'id': 1, 'ifindex': 3, 'napi-id': 162, 'type': 'rx'}

$ ./cli.py --spec ../../../Documentation/netlink/specs/netdev.yaml \
  --do napi-get --json '{"id": 162}'

{'id': 162, 'ifindex': 3, 'irq': 136}

The above output suggests that irq 136 was allocated for queue 1, which has
a NAPI ID of 162.

To double check this is correct, the IRQ to queue mapping can be verified
by checking /proc/interrupts:

$ cat /proc/interrupts  | grep 136\: | \
  awk '{print "irq: " $1 " name " $76}'

irq: 136: name i40e-vlan300-TxRx-1

Suggests that queue 1 has IRQ 136, as expected.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 drivers/net/ethernet/intel/i40e/i40e.h      |  2 +
 drivers/net/ethernet/intel/i40e/i40e_main.c | 58 +++++++++++++++++++++
 drivers/net/ethernet/intel/i40e/i40e_txrx.c |  4 ++
 3 files changed, 64 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index 2fbabcdb5bb5..5900ed5c7170 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -1267,6 +1267,8 @@ int i40e_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd);
 int i40e_open(struct net_device *netdev);
 int i40e_close(struct net_device *netdev);
 int i40e_vsi_open(struct i40e_vsi *vsi);
+void i40e_queue_set_napi(struct i40e_vsi *vsi, unsigned int queue_index,
+			 enum netdev_queue_type type, struct napi_struct *napi);
 void i40e_vlan_stripping_disable(struct i40e_vsi *vsi);
 int i40e_add_vlan_all_mac(struct i40e_vsi *vsi, s16 vid);
 int i40e_vsi_add_vlan(struct i40e_vsi *vsi, u16 vid);
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 0bdcdea0be3e..6384a0c73a05 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3448,6 +3448,58 @@ static struct xsk_buff_pool *i40e_xsk_pool(struct i40e_ring *ring)
 	return xsk_get_pool_from_qid(ring->vsi->netdev, qid);
 }
 
+/**
+ * __i40e_queue_set_napi - Set the napi instance for the queue
+ * @dev: device to which NAPI and queue belong
+ * @queue_index: Index of queue
+ * @type: queue type as RX or TX
+ * @napi: NAPI context
+ * @locked: is the rtnl_lock already held
+ *
+ * Set the napi instance for the queue. Caller indicates the lock status.
+ */
+static void
+__i40e_queue_set_napi(struct net_device *dev, unsigned int queue_index,
+		      enum netdev_queue_type type, struct napi_struct *napi,
+		      bool locked)
+{
+	if (!locked)
+		rtnl_lock();
+	netif_queue_set_napi(dev, queue_index, type, napi);
+	if (!locked)
+		rtnl_unlock();
+}
+
+/**
+ * i40e_queue_set_napi - Set the napi instance for the queue
+ * @vsi: VSI being configured
+ * @queue_index: Index of queue
+ * @type: queue type as RX or TX
+ * @napi: NAPI context
+ *
+ * Set the napi instance for the queue. The rtnl lock state is derived from the
+ * execution path.
+ */
+void
+i40e_queue_set_napi(struct i40e_vsi *vsi, unsigned int queue_index,
+		    enum netdev_queue_type type, struct napi_struct *napi)
+{
+	struct i40e_pf *pf = vsi->back;
+
+	if (!vsi->netdev)
+		return;
+
+	if (current_work() == &pf->service_task ||
+	    test_bit(__I40E_PF_RESET_REQUESTED, pf->state) ||
+	    test_bit(__I40E_DOWN, pf->state) ||
+	    test_bit(__I40E_SUSPENDED, pf->state))
+		__i40e_queue_set_napi(vsi->netdev, queue_index, type, napi,
+				      false);
+	else
+		__i40e_queue_set_napi(vsi->netdev, queue_index, type, napi,
+				      true);
+}
+
 /**
  * i40e_configure_tx_ring - Configure a transmit ring context and rest
  * @ring: The Tx ring to configure
@@ -3558,6 +3610,8 @@ static int i40e_configure_tx_ring(struct i40e_ring *ring)
 	/* cache tail off for easier writes later */
 	ring->tail = hw->hw_addr + I40E_QTX_TAIL(pf_q);
 
+	i40e_queue_set_napi(vsi, ring->queue_index, NETDEV_QUEUE_TYPE_TX,
+			    &ring->q_vector->napi);
 	return 0;
 }
 
@@ -3716,6 +3770,8 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 			 ring->queue_index, pf_q);
 	}
 
+	i40e_queue_set_napi(vsi, ring->queue_index, NETDEV_QUEUE_TYPE_RX,
+			    &ring->q_vector->napi);
 	return 0;
 }
 
@@ -4178,6 +4234,8 @@ static int i40e_vsi_request_irq_msix(struct i40e_vsi *vsi, char *basename)
 		q_vector->affinity_notify.notify = i40e_irq_affinity_notify;
 		q_vector->affinity_notify.release = i40e_irq_affinity_release;
 		irq_set_affinity_notifier(irq_num, &q_vector->affinity_notify);
+		netif_napi_set_irq(&q_vector->napi, q_vector->irq_num);
+
 		/* Spread affinity hints out across online CPUs.
 		 *
 		 * get_cpu_mask returns a static constant mask with
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 64d198ed166b..d380885ff26d 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -821,6 +821,8 @@ void i40e_clean_tx_ring(struct i40e_ring *tx_ring)
 void i40e_free_tx_resources(struct i40e_ring *tx_ring)
 {
 	i40e_clean_tx_ring(tx_ring);
+	i40e_queue_set_napi(tx_ring->vsi, tx_ring->queue_index,
+			    NETDEV_QUEUE_TYPE_TX, NULL);
 	kfree(tx_ring->tx_bi);
 	tx_ring->tx_bi = NULL;
 
@@ -1526,6 +1528,8 @@ void i40e_clean_rx_ring(struct i40e_ring *rx_ring)
 void i40e_free_rx_resources(struct i40e_ring *rx_ring)
 {
 	i40e_clean_rx_ring(rx_ring);
+	i40e_queue_set_napi(rx_ring->vsi, rx_ring->queue_index,
+			    NETDEV_QUEUE_TYPE_RX, NULL);
 	if (rx_ring->vsi->type == I40E_VSI_MAIN)
 		xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
 	rx_ring->xdp_prog = NULL;
-- 
2.25.1