Merge branch 'netkit-support-for-io_uring-zero-copy-and-af_xdp'

Daniel Borkmann says:

====================
netkit: Support for io_uring zero-copy and AF_XDP

Containers use virtual netdevs to route traffic from a physical netdev
in the host namespace. They do not have access to the physical netdev
in the host and thus can't use memory providers or AF_XDP that require
reconfiguring/restarting queues in the physical netdev.

This patchset adds the concept of queue leasing to virtual netdevs that
allow containers to use memory providers and AF_XDP at native speed.
Leased queues are bound to a real queue in a physical netdev and act
as a proxy.

Memory providers and AF_XDP operations take an ifindex and queue id,
so containers would pass in an ifindex for a virtual netdev and a queue
id of a leased queue, which then gets proxied to the underlying real
queue.

We have implemented support for this concept in netkit and tested the
latter against Nvidia ConnectX-6 (mlx5) as well as Broadcom BCM957504
(bnxt_en) 100G NICs. For more details see the individual patches.
====================

Link: https://patch.msgid.link/20260402231031.447597-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e15367373f7c0..47417b2d48a4d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2561,7 +2561,14 @@ struct net_device {
 	 * Also protects some fields in:
 	 *	struct napi_struct, struct netdev_queue, struct netdev_rx_queue
 	 *
-	 * Ordering: take after rtnl_lock.
+	 * Ordering:
+	 *
+	 * - take after rtnl_lock
+	 *
+	 * - for the case of netdev queue leasing, the netdev-scope lock is
+	 *   taken for both the virtual and the physical device; to prevent
+	 *   deadlocks, the virtual device's lock must always be acquired
+	 *   before the physical device's (see netdev_nl_queue_create_doit)
 	 */
 	struct mutex		lock;
 
@@ -3413,6 +3420,8 @@ static inline int dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
 int register_netdevice(struct net_device *dev);
 void unregister_netdevice_queue(struct net_device *dev, struct list_head *head);
 void unregister_netdevice_many(struct list_head *head);
+bool unregister_netdevice_queued(const struct net_device *dev);
+
 static inline void unregister_netdevice(struct net_device *dev)
 {
 	unregister_netdevice_queue(dev, NULL);