[Intel-wired-lan] [PATCH net-queue v1] igc: Fix trying to register an already registered xdp_rxq

[Vinicius Costa Gomes <vinicius.gomes@intel.com>]

When changing the number of RX descriptors, for example, by doing

 $ ethtool -G enp3s0 rx 1024

the XDP RX queue information (xdp_rxq) may be already registered, if
it's registered there's no need to do any thing in relation to
xdp_rxq, none of it's parameters will change if we change the number
of descriptors, for example.

Fixes: 4609ffb9f615 ("igc: Refactor XDP rxq info registration")
Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
Lennert, I added your name and email to the Reported-by tag, please
see if you are ok with it.

 drivers/net/ethernet/intel/igc/igc_main.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index e29aadbc6744..d163139161fc 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c)  2018 Intel Corporation */
 
+#include "net/xdp.h"
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/if_vlan.h>
@@ -499,12 +500,14 @@ int igc_setup_rx_resources(struct igc_ring *rx_ring)
 	u8 index = rx_ring->queue_index;
 	int size, desc_len, res;
 
-	res = xdp_rxq_info_reg(&rx_ring->xdp_rxq, ndev, index,
-			       rx_ring->q_vector->napi.napi_id);
-	if (res < 0) {
-		netdev_err(ndev, "Failed to register xdp_rxq index %u\n",
-			   index);
-		return res;
+	if (!xdp_rxq_info_is_reg(&rx_ring->xdp_rxq)) {
+		res = xdp_rxq_info_reg(&rx_ring->xdp_rxq, ndev, index,
+				       rx_ring->q_vector->napi.napi_id);
+		if (res < 0) {
+			netdev_err(ndev, "Failed to register xdp_rxq index %u\n",
+				   index);
+			return res;
+		}
 	}
 
 	size = sizeof(struct igc_rx_buffer) * rx_ring->count;
-- 
2.34.1