On 9/17/21 11:36 PM, Yajun Deng wrote:
quoted hunk ↗ jump to hunk
It no need barrier when assigning a NULL value to an RCU protected
pointer. So use RCU_INIT_POINTER() instead for more fast.
Signed-off-by: Yajun Deng <redacted>
---
net/core/rtnetlink.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 972c8cb303a5..327ca6bc6e6d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -301,7 +301,7 @@ int rtnl_unregister(int protocol, int msgtype)
}
link = rtnl_dereference(tab[msgindex]);
- rcu_assign_pointer(tab[msgindex], NULL);
+ RCU_INIT_POINTER(tab[msgindex], NULL);
rtnl_unlock();
kfree_rcu(link, rcu);
@@ -337,7 +337,7 @@ void rtnl_unregister_all(int protocol)
if (!link)
continue;
- rcu_assign_pointer(tab[msgindex], NULL);
+ RCU_INIT_POINTER(tab[msgindex], NULL);
kfree_rcu(link, rcu);
}
rtnl_unlock();
FYI, there is no memory barrier involved in
rcu_assign_pointer(tab[msgindex], NULL);
This has been the case for the last 5 years.
Your patch was not needed really.