Linux Ethernet Bridging - Oct 2017 - [Bridge] [PATCH net-next 6/7] net: bridge: Pass extack to down to netdev_master_upper_dev_link

Pass extack arg to br_add_if. Add messages for a couple of failures
and pass arg to netdev_master_upper_dev_link.

Signed-off-by: David Ahern <dsahern at gmail.com>
---
 net/bridge/br_device.c  |  2 +-
 net/bridge/br_if.c      | 15 +++++++++++----
 net/bridge/br_ioctl.c   |  2 +-
 net/bridge/br_private.h |  3 ++-
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index cb0131d70ab1..7acb77c9bd65 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -326,7 +326,7 @@ static int br_add_slave(struct net_device *dev, struct
net_device *slave_dev,
 {
 	struct net_bridge *br = netdev_priv(dev);
 
-	return br_add_if(br, slave_dev);
+	return br_add_if(br, slave_dev, extack);
 }
 
 static int br_del_slave(struct net_device *dev, struct net_device *slave_dev)
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 0a3fd727048d..59a74a414e20 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -480,7 +480,8 @@ netdev_features_t br_features_recompute(struct net_bridge
*br,
 }
 
 /* called with RTNL */
-int br_add_if(struct net_bridge *br, struct net_device *dev)
+int br_add_if(struct net_bridge *br, struct net_device *dev,
+	      struct netlink_ext_ack *extack)
 {
 	struct net_bridge_port *p;
 	int err = 0;
@@ -500,16 +501,22 @@ int br_add_if(struct net_bridge *br, struct net_device
*dev)
 		return -EINVAL;
 
 	/* No bridging of bridges */
-	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
+	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
+		NL_SET_ERR_MSG(extack,
+			       "Can not enslave a bridge to a bridge");
 		return -ELOOP;
+	}
 
 	/* Device is already being bridged */
 	if (br_port_exists(dev))
 		return -EBUSY;
 
 	/* No bridging devices that dislike that (e.g. wireless) */
-	if (dev->priv_flags & IFF_DONT_BRIDGE)
+	if (dev->priv_flags & IFF_DONT_BRIDGE) {
+		NL_SET_ERR_MSG(extack,
+			       "Device does not allow enslaving to a bridge");
 		return -EOPNOTSUPP;
+	}
 
 	p = new_nbp(br, dev);
 	if (IS_ERR(p))
@@ -540,7 +547,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 
 	dev->priv_flags |= IFF_BRIDGE_PORT;
 
-	err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, NULL);
+	err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, extack);
 	if (err)
 		goto err5;
 
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 66cd98772051..8f29103935a3 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -98,7 +98,7 @@ static int add_del_if(struct net_bridge *br, int ifindex, int
isadd)
 		return -EINVAL;
 
 	if (isadd)
-		ret = br_add_if(br, dev);
+		ret = br_add_if(br, dev, NULL);
 	else
 		ret = br_del_if(br, dev);
 
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 020c709a017f..ab4df24f7bba 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -566,7 +566,8 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 void br_port_carrier_check(struct net_bridge_port *p);
 int br_add_bridge(struct net *net, const char *name);
 int br_del_bridge(struct net *net, const char *name);
-int br_add_if(struct net_bridge *br, struct net_device *dev);
+int br_add_if(struct net_bridge *br, struct net_device *dev,
+	      struct netlink_ext_ack *extack);
 int br_del_if(struct net_bridge *br, struct net_device *dev);
 int br_min_mtu(const struct net_bridge *br);
 netdev_features_t br_features_recompute(struct net_bridge *br,
-- 
2.1.4

On Tue,  3 Oct 2017 21:58:53 -0700
David Ahern <dsahern at gmail.com> wrote:
> Pass extack arg to br_add_if. Add messages for a couple of failures
> and pass arg to netdev_master_upper_dev_link.
> 
> Signed-off-by: David Ahern <dsahern at gmail.com>
This looks good. You might want to pass the netlink_ext_ack down as
an immutable pointer (const).

Acked-by: Stephen Hemminger <stephen at networkplumber.org>