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From:   Chuang Wang <nashuiliang@gmail.com>
Cc:     Chuang Wang <nashuiliang@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v1] net: macvlan: Use built-in RCU list checking
Date:   Tue,  8 Nov 2022 20:52:54 +0800
Message-Id: <20221108125254.688234-1-nashuiliang@gmail.com>
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Precedence: bulk

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

Pass cond argument to hlist_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 <nashuiliang@gmail.com>
---
v0 -> v1:
- fix typo

 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