xdp: propagate extended ack to XDP setup

Drivers usually have a number of restrictions for running XDP
- most common being buffer sizes, LRO and number of rings.
Even though some drivers try to be helpful and print error
messages experience shows that users don't often consult
kernel logs on netlink errors.  Try to use the new extended
ack mechanism to carry the message back to user space.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6847714a5ae3..9c23bd2efb56 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -813,11 +813,16 @@ enum xdp_netdev_command {
 	XDP_QUERY_PROG,
 };
 
+struct netlink_ext_ack;
+
 struct netdev_xdp {
 	enum xdp_netdev_command command;
 	union {
 		/* XDP_SETUP_PROG */
-		struct bpf_prog *prog;
+		struct {
+			struct bpf_prog *prog;
+			struct netlink_ext_ack *extack;
+		};
 		/* XDP_QUERY_PROG */
 		bool prog_attached;
 	};
@@ -3291,7 +3296,8 @@ int dev_get_phys_port_id(struct net_device *dev,
 int dev_get_phys_port_name(struct net_device *dev,
 			   char *name, size_t len);
 int dev_change_proto_down(struct net_device *dev, bool proto_down);
-int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags);
+int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
+		      int fd, u32 flags);
 struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev);
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 				    struct netdev_queue *txq, int *ret);