2022-11-11 02:07:16

by Chuang Wang

Subject: [PATCH net v2] net: macvlan: Use built-in RCU list checking

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.

Fixes: 79cf79abce71 ("macvlan: add source mode")
Signed-off-by: Chuang Wang <[email protected]>
---
v1 -> v2:
- fix the patch Subject, add a Fixed tag

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 578897aaada0..b8cc55b2d721 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;
@@ -1647,7 +1647,7 @@ 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

2022-11-14 11:19:00

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net v2] net: macvlan: Use built-in RCU list checking

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

On Fri, 11 Nov 2022 09:41:30 +0800 you wrote:
> 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:
>
> [...]

Here is the summary with links:
- [net,v2] net: macvlan: Use built-in RCU list checking
https://git.kernel.org/netdev/net/c/5df1341ea822

You are awesome, thank you!
--
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