Merge branch 'xdp-netlink-ext-ack'

Jakub Kicinski says:

====================
xdp: use netlink extended ACK reporting

This series is an attempt to make XDP more user friendly by
enabling exploiting the recently added netlink extended ACK
reporting to carry messages to user space.

David Ahern's iproute2 ext ack patches for ip link are sufficient
to show the errors like this:

Error: nfp: MTU too large w/ XDP enabled

Where the message is coming directly from the driver.  There could
still be a bit of a leap for a complete novice from the message
above to the right settings, but it's a big improvement over the
standard "Invalid argument" message.

v1/non-rfc:
 - add a separate macro in patch 1;
 - add KBUILD_MODNAME as part of the message (Daniel);
 - don't print the error to logs in patch 1.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 12 insertions, 6 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 8371a01eee87..35a06cebb282 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6854,12 +6854,14 @@ EXPORT_SYMBOL(dev_change_proto_down);
 /**
  *	dev_change_xdp_fd - set or clear a bpf program for a device rx path
  *	@dev: device
+ *	@extact: netlink extended ack
  *	@fd: new program fd or negative value to clear
  *	@flags: xdp-related flags
  *
  *	Set or clear a bpf program for a device
  */
-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)
 {
 	int (*xdp_op)(struct net_device *dev, struct netdev_xdp *xdp);
 	const struct net_device_ops *ops = dev->netdev_ops;
@@ -6892,6 +6894,7 @@ int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags)
 
 	memset(&xdp, 0, sizeof(xdp));
 	xdp.command = XDP_SETUP_PROG;
+	xdp.extack = extack;
 	xdp.prog = prog;
 
 	err = xdp_op(dev, &xdp);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9031a6c8bfa7..6e67315ec368 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1919,6 +1919,7 @@ static int do_set_master(struct net_device *dev, int ifindex)
 #define DO_SETLINK_NOTIFY	0x03
 static int do_setlink(const struct sk_buff *skb,
 		      struct net_device *dev, struct ifinfomsg *ifm,
+		      struct netlink_ext_ack *extack,
 		      struct nlattr **tb, char *ifname, int status)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
@@ -2201,7 +2202,7 @@ static int do_setlink(const struct sk_buff *skb,
 		}
 
 		if (xdp[IFLA_XDP_FD]) {
-			err = dev_change_xdp_fd(dev,
+			err = dev_change_xdp_fd(dev, extack,
 						nla_get_s32(xdp[IFLA_XDP_FD]),
 						xdp_flags);
 			if (err)
@@ -2261,7 +2262,7 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		goto errout;
 
-	err = do_setlink(skb, dev, ifm, tb, ifname, 0);
+	err = do_setlink(skb, dev, ifm, extack, tb, ifname, 0);
 errout:
 	return err;
 }
@@ -2423,6 +2424,7 @@ EXPORT_SYMBOL(rtnl_create_link);
 static int rtnl_group_changelink(const struct sk_buff *skb,
 		struct net *net, int group,
 		struct ifinfomsg *ifm,
+		struct netlink_ext_ack *extack,
 		struct nlattr **tb)
 {
 	struct net_device *dev, *aux;
@@ -2430,7 +2432,7 @@ static int rtnl_group_changelink(const struct sk_buff *skb,
 
 	for_each_netdev_safe(net, dev, aux) {
 		if (dev->group == group) {
-			err = do_setlink(skb, dev, ifm, tb, NULL, 0);
+			err = do_setlink(skb, dev, ifm, extack, tb, NULL, 0);
 			if (err < 0)
 				return err;
 		}
@@ -2576,14 +2578,15 @@ replay:
 				status |= DO_SETLINK_NOTIFY;
 			}
 
-			return do_setlink(skb, dev, ifm, tb, ifname, status);
+			return do_setlink(skb, dev, ifm, extack, tb, ifname,
+					  status);
 		}
 
 		if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
 			if (ifm->ifi_index == 0 && tb[IFLA_GROUP])
 				return rtnl_group_changelink(skb, net,
 						nla_get_u32(tb[IFLA_GROUP]),
-						ifm, tb);
+						ifm, extack, tb);
 			return -ENODEV;
 		}