Similarly what we do for net_mp_{open,close}_rxq for mapped queues, proxy
also the xsk_{reg,clear}_pool_at_qid via netif_get_rx_queue_peer_locked
such that when a virtual netdev picked a mapped rxq, the request gets
through to the real rxq in the physical netdev. The proxying is only
relevant for queue_id < dev->real_num_rx_queues since right now its only
supported for rxqs.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
---
 net/xdp/xsk.c | 48 +++++++++++++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 13 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 6ae9ad5f27ad..872b243b7fcc 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -23,6 +23,8 @@
 #include <linux/netdevice.h>
 #include <linux/rculist.h>
 #include <linux/vmalloc.h>
+
+#include <net/netdev_queues.h>
 #include <net/xdp_sock_drv.h>
 #include <net/busy_poll.h>
 #include <net/netdev_lock.h>
@@ -124,10 +126,18 @@ EXPORT_SYMBOL(xsk_get_pool_from_qid);
 
 void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
 {
-	if (queue_id < dev->num_rx_queues)
-		dev->_rx[queue_id].pool = NULL;
-	if (queue_id < dev->num_tx_queues)
-		dev->_tx[queue_id].pool = NULL;
+	struct net_device *orig_dev = dev;
+	unsigned int id = queue_id;
+
+	if (id < dev->real_num_rx_queues)
+		WARN_ON_ONCE(!netif_get_rx_queue_peer_locked(&dev, &id));
+
+	if (id < dev->real_num_rx_queues)
+		dev->_rx[id].pool = NULL;
+	if (id < dev->real_num_tx_queues)
+		dev->_tx[id].pool = NULL;
+
+	netif_put_rx_queue_peer_locked(orig_dev, dev);
 }
 
 /* The buffer pool is stored both in the _rx struct and the _tx struct as we do
@@ -137,17 +147,29 @@ void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
 			u16 queue_id)
 {
-	if (queue_id >= max_t(unsigned int,
-			      dev->real_num_rx_queues,
-			      dev->real_num_tx_queues))
-		return -EINVAL;
+	struct net_device *orig_dev = dev;
+	unsigned int id = queue_id;
+	int ret = 0;
 
-	if (queue_id < dev->real_num_rx_queues)
-		dev->_rx[queue_id].pool = pool;
-	if (queue_id < dev->real_num_tx_queues)
-		dev->_tx[queue_id].pool = pool;
+	if (id >= max(dev->real_num_rx_queues,
+		      dev->real_num_tx_queues))
+		return -EINVAL;
+	if (id < dev->real_num_rx_queues) {
+		if (!netif_get_rx_queue_peer_locked(&dev, &id))
+			return -EBUSY;
+		if (xsk_get_pool_from_qid(dev, id)) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
 
-	return 0;
+	if (id < dev->real_num_rx_queues)
+		dev->_rx[id].pool = pool;
+	if (id < dev->real_num_tx_queues)
+		dev->_tx[id].pool = pool;
+out:
+	netif_put_rx_queue_peer_locked(orig_dev, dev);
+	return ret;
 }
 
 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len,
-- 
2.43.0