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hsr: no longer rely on RTNL in hsr_fill_info()

Browse Source 
hsr_fill_info() used hsr_port_get_hsr(), which walks hsr->ports
with hsr_for_each_port_rtnl(), forcing "ip link show" dumps to
hold RTNL.

hsr->ports is an RCU protected list: ports are added with
list_add_tail_rcu(), removed with list_del_rcu() and freed with
kfree_rcu(), and the data path already iterates over it with
hsr_for_each_port().

Add a local RCU variant of hsr_port_get_hsr() and use it from
hsr_fill_info() under rcu_read_lock().

The remaining fields (sup_multicast_addr, prot_version) are set
once at device creation. hsr->sequence_nr is now read with
READ_ONCE(), since the transmit paths increment it under
hsr->seqnr_lock only.

Also add missing const qualifiers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260916132822.1791040-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-09-16 13:28:22 +00:00 committed by Jakub Kicinski
parent 41c57cf050
commit 9f8b888ced
1 changed files with 27 additions and 10 deletions
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37
net/hsr/hsr_netlink.c
View File

@ -147,44 +147,61 @@ static void hsr_dellink(struct net_device *dev, struct list_head *head)
unregister_netdevice_queue(dev, head);
}
static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
/* RCU variant of hsr_port_get_hsr() */
static struct hsr_port *hsr_port_get_hsr_rcu(const struct hsr_priv *hsr,
enum hsr_port_type pt)
{
struct hsr_priv *hsr = netdev_priv(dev);
u8 proto = HSR_PROTOCOL_HSR;
struct hsr_port *port;
port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
hsr_for_each_port(hsr, port)
if (port->type == pt)
return port;
return NULL;
}
static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
const struct hsr_priv *hsr = netdev_priv(dev);
const struct hsr_port *port;
u8 proto = HSR_PROTOCOL_HSR;
rcu_read_lock();
port = hsr_port_get_hsr_rcu(hsr, HSR_PT_SLAVE_A);
if (port) {
if (nla_put_u32(skb, IFLA_HSR_SLAVE1, port->dev->ifindex))
goto nla_put_failure;
}
port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
port = hsr_port_get_hsr_rcu(hsr, HSR_PT_SLAVE_B);
if (port) {
if (nla_put_u32(skb, IFLA_HSR_SLAVE2, port->dev->ifindex))
goto nla_put_failure;
}
port = hsr_port_get_hsr(hsr, HSR_PT_INTERLINK);
port = hsr_port_get_hsr_rcu(hsr, HSR_PT_INTERLINK);
if (port) {
if (nla_put_u32(skb, IFLA_HSR_INTERLINK, port->dev->ifindex))
goto nla_put_failure;
}
rcu_read_unlock();
if (nla_put(skb, IFLA_HSR_SUPERVISION_ADDR, ETH_ALEN,
hsr->sup_multicast_addr) ||
nla_put_u16(skb, IFLA_HSR_SEQ_NR, hsr->sequence_nr))
goto nla_put_failure;
nla_put_u16(skb, IFLA_HSR_SEQ_NR, READ_ONCE(hsr->sequence_nr)))
return -EMSGSIZE;
if (hsr->prot_version == PRP_V1)
proto = HSR_PROTOCOL_PRP;
else if (nla_put_u8(skb, IFLA_HSR_VERSION, hsr->prot_version))
goto nla_put_failure;
return -EMSGSIZE;
if (nla_put_u8(skb, IFLA_HSR_PROTOCOL, proto))
goto nla_put_failure;
return -EMSGSIZE;
return 0;
nla_put_failure:
rcu_read_unlock();
return -EMSGSIZE;
}