igb: Introduce igb_xdp_is_enabled()

Introduce igb_xdp_is_enabled() to check if an XDP program is assigned to
the device. Use that wherever xdp_prog is read and evaluated.

Signed-off-by: Sriram Yagnaraman <[email protected]>
[Kurt: Split patches and use READ_ONCE()]
Signed-off-by: Kurt Kanzenbach <[email protected]>
Acked-by: Maciej Fijalkowski <[email protected]>
Tested-by: George Kuruvinakunnel <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: sriramy

drivers/net/ethernet/intel/igb/igb.h

@@ -826,6 +826,11 @@ static inline struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adap
 	return adapter->tx_ring[r_idx];
 }
 
+static inline bool igb_xdp_is_enabled(struct igb_adapter *adapter)
+{
+	return !!READ_ONCE(adapter->xdp_prog);
+}
+
 int igb_add_filter(struct igb_adapter *adapter,
 		   struct igb_nfc_filter *input);
 int igb_erase_filter(struct igb_adapter *adapter,

drivers/net/ethernet/intel/igb/igb_main.c

@@ -2930,7 +2930,8 @@ int igb_xdp_xmit_back(struct igb_adapter *adapter, struct xdp_buff *xdp)
 	/* During program transitions its possible adapter->xdp_prog is assigned
 	 * but ring has not been configured yet. In this case simply abort xmit.
 	 */
-	tx_ring = adapter->xdp_prog ? igb_xdp_tx_queue_mapping(adapter) : NULL;
+	tx_ring = igb_xdp_is_enabled(adapter) ?
+		igb_xdp_tx_queue_mapping(adapter) : NULL;
 	if (unlikely(!tx_ring))
 		return IGB_XDP_CONSUMED;
 
@@ -2963,7 +2964,8 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 	/* During program transitions its possible adapter->xdp_prog is assigned
 	 * but ring has not been configured yet. In this case simply abort xmit.
 	 */
-	tx_ring = adapter->xdp_prog ? igb_xdp_tx_queue_mapping(adapter) : NULL;
+	tx_ring = igb_xdp_is_enabled(adapter) ?
+		igb_xdp_tx_queue_mapping(adapter) : NULL;
 	if (unlikely(!tx_ring))
 		return -ENXIO;
 
@@ -6597,7 +6599,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	int max_frame = new_mtu + IGB_ETH_PKT_HDR_PAD;
 
-	if (adapter->xdp_prog) {
+	if (igb_xdp_is_enabled(adapter)) {
 		int i;
 
 		for (i = 0; i < adapter->num_rx_queues; i++) {