[Intel-wired-lan] [RFC net-next 1/2] igc: Link IRQs to NAPI instances

[Joe Damato <jdamato@fastly.com>]

Link IRQs to NAPI instances via netdev-genl API so that users can query
this information with netlink.

Compare the output of /proc/interrupts (noting that IRQ 144 is the
"other" IRQ which does not appear to have a NAPI instance):

$ cat /proc/interrupts | grep enp86s0 | cut --delimiter=":" -f1
 144
 145
 146
 147
 148

The output from netlink shows the mapping of NAPI IDs to IRQs (again
noting that 144 is absent as it is the "other" IRQ):

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

[{'id': 8196, 'ifindex': 2, 'irq': 148},
 {'id': 8195, 'ifindex': 2, 'irq': 147},
 {'id': 8194, 'ifindex': 2, 'irq': 146},
 {'id': 8193, 'ifindex': 2, 'irq': 145}]

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 drivers/net/ethernet/intel/igc/igc.h      | 1 +
 drivers/net/ethernet/intel/igc/igc_main.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index eac0f966e0e4..e757ba53f165 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -593,6 +593,7 @@ struct igc_q_vector {
 
 	struct rcu_head rcu;    /* to avoid race with update stats on free */
 	char name[IFNAMSIZ + 9];
+	int irq;
 
 	/* for dynamic allocation of rings associated with this q_vector */
 	struct igc_ring ring[] ____cacheline_internodealigned_in_smp;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 6e70bca15db1..7964bbedb16c 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -5576,6 +5576,9 @@ static int igc_request_msix(struct igc_adapter *adapter)
 				  q_vector);
 		if (err)
 			goto err_free;
+
+		netif_napi_set_irq(&q_vector->napi,
+				   adapter->msix_entries[vector].vector);
 	}
 
 	igc_configure_msix(adapter);
-- 
2.25.1