netdev - [net-next 1/2] ena: Link IRQs to NAPI instances

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Message-Id: <20240930195617.37369-2-jdamato@fastly.com>
Date: Mon, 30 Sep 2024 19:56:12 +0000
From: Joe Damato <jdamato@...tly.com>
To: netdev@...r.kernel.org
Cc: Joe Damato <jdamato@...tly.com>,
	Shay Agroskin <shayagr@...zon.com>,
	Arthur Kiyanovski <akiyano@...zon.com>,
	David Arinzon <darinzon@...zon.com>,
	Noam Dagan <ndagan@...zon.com>,
	Saeed Bishara <saeedb@...zon.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Kamal Heib <kheib@...hat.com>,
	linux-kernel@...r.kernel.org (open list)
Subject: [net-next 1/2] ena: Link IRQs to NAPI instances

Link IRQs to NAPI instances with netif_napi_set_irq. This information
can be queried with the netdev-genl API. Note that the ENA device
appears to allocate an IRQ for management purposes which does not have a
NAPI associated with it; this commit takes this into consideration to
accurately construct a map between IRQs and NAPI instances.

Compare the output of /proc/interrupts for my ena device with the output of
netdev-genl after applying this patch:

$ cat /proc/interrupts | grep enp55s0 | cut -f1 --delimiter=':'
 94
 95
 96
 97
 98
 99
100
101

$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
			 --dump napi-get --json='{"ifindex": 2}'

[{'id': 8208, 'ifindex': 2, 'irq': 101},
 {'id': 8207, 'ifindex': 2, 'irq': 100},
 {'id': 8206, 'ifindex': 2, 'irq': 99},
 {'id': 8205, 'ifindex': 2, 'irq': 98},
 {'id': 8204, 'ifindex': 2, 'irq': 97},
 {'id': 8203, 'ifindex': 2, 'irq': 96},
 {'id': 8202, 'ifindex': 2, 'irq': 95},
 {'id': 8201, 'ifindex': 2, 'irq': 94}]

Signed-off-by: Joe Damato <jdamato@...tly.com>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index c5b50cfa935a..e88de5e426ef 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1679,7 +1679,7 @@ static int ena_request_io_irq(struct ena_adapter *adapter)
 	u32 io_queue_count = adapter->num_io_queues + adapter->xdp_num_queues;
 	unsigned long flags = 0;
 	struct ena_irq *irq;
-	int rc = 0, i, k;
+	int rc = 0, i, k, irq_idx;
 
 	if (!test_bit(ENA_FLAG_MSIX_ENABLED, &adapter->flags)) {
 		netif_err(adapter, ifup, adapter->netdev,
@@ -1705,6 +1705,16 @@ static int ena_request_io_irq(struct ena_adapter *adapter)
 		irq_set_affinity_hint(irq->vector, &irq->affinity_hint_mask);
 	}
 
+	/* Now that IO IRQs have been successfully allocated map them to the
+	 * corresponding IO NAPI instance. Note that the mgmnt IRQ does not
+	 * have a NAPI, so care must be taken to correctly map IRQs to NAPIs.
+	 */
+	for (i = 0; i < io_queue_count; i++) {
+		irq_idx = ENA_IO_IRQ_IDX(i);
+		irq = &adapter->irq_tbl[irq_idx];
+		netif_napi_set_irq(&adapter->ena_napi[i].napi, irq->vector);
+	}
+
 	return rc;
 
 err:
-- 
2.43.0