[PATCH net-next v3 10/15] xsk: Proxy pool management for mapped queues

[Daniel Borkmann <daniel@iogearbox.net>]

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
such that when a virtual netdev picked a mapped rxq, the request gets
through to the real rxq in the physical netdev.

Change the function signatures for queue_id to unsigned int in order
to pass the queue_id parameter into __netif_get_rx_queue_peer. 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>
---
 include/net/xdp_sock_drv.h |  4 ++--
 net/xdp/xsk.c              | 33 ++++++++++++++++++++++++++++-----
 net/xdp/xsk.h              |  5 ++---
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index 242e34f771cc..25c37fab00bc 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -29,7 +29,7 @@ bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc);
 u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 max);
 void xsk_tx_release(struct xsk_buff_pool *pool);
 struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
-					    u16 queue_id);
+					    unsigned int queue_id);
 void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool);
 void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool);
 void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool);
@@ -296,7 +296,7 @@ static inline void xsk_tx_release(struct xsk_buff_pool *pool)
 }
 
 static inline struct xsk_buff_pool *
-xsk_get_pool_from_qid(struct net_device *dev, u16 queue_id)
+xsk_get_pool_from_qid(struct net_device *dev, unsigned int queue_id)
 {
 	return NULL;
 }
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 985e0cac965d..9e55ea0f5fde 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>
@@ -111,7 +113,7 @@ bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool)
 EXPORT_SYMBOL(xsk_uses_need_wakeup);
 
 struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
-					    u16 queue_id)
+					    unsigned int queue_id)
 {
 	if (queue_id < dev->real_num_rx_queues)
 		return dev->_rx[queue_id].pool;
@@ -122,12 +124,19 @@ struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
 }
 EXPORT_SYMBOL(xsk_get_pool_from_qid);
 
-void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
+void xsk_clear_pool_at_qid(struct net_device *dev, unsigned int queue_id)
 {
+	bool needs_unlock = false;
+
+	if (queue_id < dev->real_num_rx_queues)
+		WARN_ON_ONCE(!netif_get_rx_queue_peer_locked(&dev, &queue_id,
+							     &needs_unlock));
 	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;
+	if (needs_unlock)
+		netdev_unlock(dev);
 }
 
 /* The buffer pool is stored both in the _rx struct and the _tx struct as we do
@@ -135,14 +144,26 @@ void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
  * This might also change during run time.
  */
 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
-			u16 queue_id)
+			unsigned int queue_id)
 {
+	bool needs_unlock = false;
+	int ret = 0;
+
 	if (queue_id >= max_t(unsigned int,
 			      dev->real_num_rx_queues,
 			      dev->real_num_tx_queues))
 		return -EINVAL;
 	if (xsk_get_pool_from_qid(dev, queue_id))
 		return -EBUSY;
+	if (queue_id < dev->real_num_rx_queues) {
+		if (!netif_get_rx_queue_peer_locked(&dev, &queue_id,
+						    &needs_unlock))
+			return -EBUSY;
+	}
+	if (xsk_get_pool_from_qid(dev, queue_id)) {
+		ret = -EBUSY;
+		goto out;
+	}
 
 	pool->netdev = dev;
 	pool->queue_id = queue_id;
@@ -151,8 +172,10 @@ int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
 		dev->_rx[queue_id].pool = pool;
 	if (queue_id < dev->real_num_tx_queues)
 		dev->_tx[queue_id].pool = pool;
-
-	return 0;
+out:
+	if (needs_unlock)
+		netdev_unlock(dev);
+	return ret;
 }
 
 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len,
diff --git a/net/xdp/xsk.h b/net/xdp/xsk.h
index a4bc4749faac..54d9a7736fd2 100644
--- a/net/xdp/xsk.h
+++ b/net/xdp/xsk.h
@@ -41,8 +41,7 @@ static inline struct xdp_sock *xdp_sk(struct sock *sk)
 
 void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
 			     struct xdp_sock __rcu **map_entry);
-void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id);
+void xsk_clear_pool_at_qid(struct net_device *dev, unsigned int queue_id);
 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
-			u16 queue_id);
-
+			unsigned int queue_id);
 #endif /* XSK_H_ */
-- 
2.43.0