[PATCH net-next v2 3/6] rtnetlink: add helper to dump qdisc name
From: Florian Westphal <fw@strlen.de>
Date: 2017-09-22 06:10:01
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
We can use rcu here to make this safe even if we would not hold rtnl: qdisc_destroy uses call_rcu to free the Qdisc struct. Signed-off-by: Florian Westphal <fw@strlen.de> --- net/core/rtnetlink.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index c801212ee40e..ad3f27da37a8 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -1332,6 +1332,19 @@ static int nla_put_iflink(struct sk_buff *skb, const struct net_device *dev) return nla_put_u32(skb, IFLA_LINK, ifindex); } +static int nla_put_qdisc(struct sk_buff *skb, struct net_device *dev) +{ + struct Qdisc *q; + int ret = 0; + + rcu_read_lock(); + q = READ_ONCE(dev->qdisc); + if (q) + ret = nla_put_string(skb, IFLA_QDISC, q->ops->id); + rcu_read_unlock(); + return ret; +} + 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,
@@ -1372,8 +1385,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 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)) || + nla_put_qdisc(skb, dev) || (dev->ifalias && nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)) || nla_put_u32(skb, IFLA_CARRIER_CHANGES,
--
2.13.5