igc: Fix XSK queue NAPI ID mapping

In commit b659698 ("igc: Link queues to NAPI instances"), the XSK
queues were incorrectly unmapped from their NAPI instances. After
discussion on the mailing list and the introduction of a test to codify
the expected behavior, we can see that the unmapping causes the
check_xsk test to fail:

NETIF=enp86s0 ./tools/testing/selftests/drivers/net/queues.py

[...]
  # Check|     ksft_eq(q.get('xsk', None), {},
  # Check failed None != {} xsk attr on queue we configured
  not ok 4 queues.check_xsk

After this commit, the test passes:

  ok 4 queues.check_xsk

Note that the test itself is only in net-next, so I tested this change
by applying it to my local net-next tree, booting, and running the test.

Cc: stable@vger.kernel.org
Fixes: b659698 ("igc: Link queues to NAPI instances")
Signed-off-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Author: jdamato-fsly

drivers/net/ethernet/intel/igc/igc.h

@@ -337,8 +337,6 @@ struct igc_adapter {
 	struct igc_led_classdev *leds;
 };
 
-void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx,
-			struct napi_struct *napi);
 void igc_up(struct igc_adapter *adapter);
 void igc_down(struct igc_adapter *adapter);
 int igc_open(struct net_device *netdev);

drivers/net/ethernet/intel/igc/igc_main.c

@@ -5022,8 +5022,8 @@ static int igc_sw_init(struct igc_adapter *adapter)
 	return 0;
 }
 
-void igc_set_queue_napi(struct igc_adapter *adapter, int vector,
-			struct napi_struct *napi)
+static void igc_set_queue_napi(struct igc_adapter *adapter, int vector,
+			       struct napi_struct *napi)
 {
 	struct igc_q_vector *q_vector = adapter->q_vector[vector];
 

drivers/net/ethernet/intel/igc/igc_xdp.c

@@ -97,7 +97,6 @@ static int igc_xdp_enable_pool(struct igc_adapter *adapter,
 		napi_disable(napi);
 	}
 
-	igc_set_queue_napi(adapter, queue_id, NULL);
 	set_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
 	set_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags);
 
@@ -147,7 +146,6 @@ static int igc_xdp_disable_pool(struct igc_adapter *adapter, u16 queue_id)
 	xsk_pool_dma_unmap(pool, IGC_RX_DMA_ATTR);
 	clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
 	clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags);
-	igc_set_queue_napi(adapter, queue_id, napi);
 
 	if (needs_reset) {
 		napi_enable(napi);