diff mbox series

[net-next,v3,2/6] rtnetlink: add helper to put master and link ifindexes

Message ID 20170923192636.3932-3-fw@strlen.de
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series rtnetlink: preparation patches for further rtnl lock pushdown/removal | expand

Commit Message

Florian Westphal Sept. 23, 2017, 7:26 p.m. UTC 
rtnl_fill_ifinfo currently requires caller to hold the rtnl mutex.
Unfortunately the function is quite large which makes it harder to see
which spots require the lock, which spots assume it and which ones could
do without.

Add helpers to factor out the ifindex dumping, one can use rcu to avoid
rtnl dependency.

Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 no changes since v2.
 net/core/rtnetlink.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a78fd61da0ec..c801212ee40e 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1307,6 +1307,31 @@  static u32 rtnl_get_event(unsigned long event)
 	return rtnl_event_type;
 }
 
+static int put_master_ifindex(struct sk_buff *skb, struct net_device *dev)
+{
+	const struct net_device *upper_dev;
+	int ret = 0;
+
+	rcu_read_lock();
+
+	upper_dev = netdev_master_upper_dev_get_rcu(dev);
+	if (upper_dev)
+		ret = nla_put_u32(skb, IFLA_MASTER, upper_dev->ifindex);
+
+	rcu_read_unlock();
+	return ret;
+}
+
+static int nla_put_iflink(struct sk_buff *skb, const struct net_device *dev)
+{
+	int ifindex = dev_get_iflink(dev);
+
+	if (dev->ifindex == ifindex)
+		return 0;
+
+	return nla_put_u32(skb, IFLA_LINK, ifindex);
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 			    int type, u32 pid, u32 seq, u32 change,
 			    unsigned int flags, u32 ext_filter_mask,
@@ -1316,7 +1341,6 @@  static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	struct nlmsghdr *nlh;
 	struct nlattr *af_spec;
 	struct rtnl_af_ops *af_ops;
-	struct net_device *upper_dev = netdev_master_upper_dev_get(dev);
 
 	ASSERT_RTNL();
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);
@@ -1345,10 +1369,8 @@  static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
-	    (dev->ifindex != dev_get_iflink(dev) &&
-	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))) ||
-	    (upper_dev &&
-	     nla_put_u32(skb, IFLA_MASTER, upper_dev->ifindex)) ||
+	    nla_put_iflink(skb, dev) ||
+	    put_master_ifindex(skb, dev) ||
 	    nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) ||
 	    (dev->qdisc &&
 	     nla_put_string(skb, IFLA_QDISC, dev->qdisc->ops->id)) ||