ixgbe: add tracking of AF_XDP zero-copy state for each queue pair

Here, we add a bitmap to the ixgbe_adapter that tracks if a
certain queue pair has been "zero-copy enabled" via the ndo_bpf.
The bitmap is used in ixgbe_xsk_umem, and enables zero-copy if
and only if XDP is enabled, the corresponding qid in the bitmap
is set, and the umem is non-NULL;

Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -635,6 +635,7 @@ struct ixgbe_adapter {
 	/* XDP */
 	int num_xdp_queues;
 	struct ixgbe_ring *xdp_ring[MAX_XDP_QUEUES];
+	unsigned long *af_xdp_zc_qps; /* tracks AF_XDP ZC enabled rings */
 
 	/* TX */
 	struct ixgbe_ring *tx_ring[MAX_TX_QUEUES] ____cacheline_aligned_in_smp;

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -6288,6 +6288,10 @@ static int ixgbe_sw_init(struct ixgbe_adapter *adapter,
 	if (ixgbe_init_rss_key(adapter))
 		return -ENOMEM;
 
+	adapter->af_xdp_zc_qps = bitmap_zalloc(MAX_XDP_QUEUES, GFP_KERNEL);
+	if (!adapter->af_xdp_zc_qps)
+		return -ENOMEM;
+
 	/* Set MAC specific capability flags and exceptions */
 	switch (hw->mac.type) {
 	case ixgbe_mac_82598EB:
@@ -11161,6 +11165,7 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	kfree(adapter->jump_tables[0]);
 	kfree(adapter->mac_table);
 	kfree(adapter->rss_key);
+	bitmap_free(adapter->af_xdp_zc_qps);
 err_ioremap:
 	disable_dev = !test_and_set_bit(__IXGBE_DISABLED, &adapter->state);
 	free_netdev(netdev);
@@ -11249,6 +11254,7 @@ static void ixgbe_remove(struct pci_dev *pdev)
 
 	kfree(adapter->mac_table);
 	kfree(adapter->rss_key);
+	bitmap_free(adapter->af_xdp_zc_qps);
 	disable_dev = !test_and_set_bit(__IXGBE_DISABLED, &adapter->state);
 	free_netdev(netdev);
 

drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c

@@ -15,7 +15,8 @@ struct xdp_umem *ixgbe_xsk_umem(struct ixgbe_adapter *adapter,
 	int qid = ring->ring_idx;
 
 	if (!adapter->xsk_umems || !adapter->xsk_umems[qid] ||
-	    qid >= adapter->num_xsk_umems || !xdp_on)
+	    qid >= adapter->num_xsk_umems || !xdp_on ||
+	    !test_bit(qid, adapter->af_xdp_zc_qps))
 		return NULL;
 
 	return adapter->xsk_umems[qid];
@@ -143,6 +144,7 @@ static int ixgbe_xsk_umem_enable(struct ixgbe_adapter *adapter,
 	if (if_running)
 		ixgbe_txrx_ring_disable(adapter, qid);
 
+	set_bit(qid, adapter->af_xdp_zc_qps);
 	err = ixgbe_add_xsk_umem(adapter, umem, qid);
 	if (err)
 		return err;
@@ -173,6 +175,7 @@ static int ixgbe_xsk_umem_disable(struct ixgbe_adapter *adapter, u16 qid)
 	if (if_running)
 		ixgbe_txrx_ring_disable(adapter, qid);
 
+	clear_bit(qid, adapter->af_xdp_zc_qps);
 	ixgbe_xsk_umem_dma_unmap(adapter, adapter->xsk_umems[qid]);
 	ixgbe_remove_xsk_umem(adapter, qid);