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[PATCH] net: macvlan: Use built-in RCU list checking

From: Chuang Wang <hidden>
Date: 2022-11-08 12:46:42
Also in: lkml
Subsystem: networking drivers, the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence false lockdep
warning when CONFIG_PROVE_RCU_LIST is enabled.

Execute as follow:

 ip link add link eth0 type macvlan mode source macaddr add <MAC-ADDR>

The rtnl_lock is held when macvlan_hash_lookup_source() or
macvlan_fill_info_macaddr() are called in the non-RCU read side section.
So, pass lockdep_rtnl_is_held() to silence false lockdep warning.

Signed-off-by: Chuang Wang <redacted>
---
 drivers/net/macvlan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index c58fea63be7d..deb7929004a7 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -141,7 +141,7 @@ static struct macvlan_source_entry *macvlan_hash_lookup_source(
 	u32 idx = macvlan_eth_hash(addr);
 	struct hlist_head *h = &vlan->port->vlan_source_hash[idx];
 
-	hlist_for_each_entry_rcu(entry, h, hlist) {
+	hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) {
 		if (ether_addr_equal_64bits(entry->addr, addr) &&
 		    entry->vlan == vlan)
 			return entry;
@@ -1645,7 +1645,7 @@ static int macvlan_fill_info_macaddr(struct sk_buff *skb,
 	struct hlist_head *h = &vlan->port->vlan_source_hash[i];
 	struct macvlan_source_entry *entry;
 
-	hlist_for_each_entry_rcu(entry, h, hlist) {
+	hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) {
 		if (entry->vlan != vlan)
 			continue;
 		if (nla_put(skb, IFLA_MACVLAN_MACADDR, ETH_ALEN, entry->addr))
-- 
2.37.2
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