[Patch net-next] ipv4: remove inet_addr_hash_lock in devinet.c

[Patch net-next] ipv4: remove inet_addr_hash_lock in devinet.c

[Cong Wang]

All the callers hold RTNL lock, so there is no need to use inet_addr_hash_lock
to protect the hash list.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

---
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index bdbf68b..e497700 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -106,7 +106,6 @@ static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
 #define IN4_ADDR_HSIZE		(1U << IN4_ADDR_HSIZE_SHIFT)
 
 static struct hlist_head inet_addr_lst[IN4_ADDR_HSIZE];
-static DEFINE_SPINLOCK(inet_addr_hash_lock);
 
 static u32 inet_addr_hash(struct net *net, __be32 addr)
 {
@@ -119,16 +118,12 @@ static void inet_hash_insert(struct net *net, struct in_ifaddr *ifa)
 {
 	u32 hash = inet_addr_hash(net, ifa->ifa_local);
 
-	spin_lock(&inet_addr_hash_lock);
 	hlist_add_head_rcu(&ifa->hash, &inet_addr_lst[hash]);
-	spin_unlock(&inet_addr_hash_lock);
 }
 
 static void inet_hash_remove(struct in_ifaddr *ifa)
 {
-	spin_lock(&inet_addr_hash_lock);
 	hlist_del_init_rcu(&ifa->hash);
-	spin_unlock(&inet_addr_hash_lock);
 }
 
 /**

Re: [Patch net-next] ipv4: remove inet_addr_hash_lock in devinet.c

[David Miller]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Mon,  5 May 2014 11:46:50 -0700

> All the callers hold RTNL lock, so there is no need to use inet_addr_hash_lock
> to protect the hash list.
> 
> Cc: David S. Miller <davem@davemloft.net>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

If you are going to do this, please add ASSERT_RTNL() to these two locations
at the same time.

Thank you.

Re: [Patch net-next] ipv4: remove inet_addr_hash_lock in devinet.c

[Cong Wang]

On Mon, May 5, 2014 at 1:35 PM, David Miller <davem@davemloft.net> wrote:
> From: Cong Wang <xiyou.wangcong@gmail.com>
> Date: Mon,  5 May 2014 11:46:50 -0700
>
>> All the callers hold RTNL lock, so there is no need to use inet_addr_hash_lock
>> to protect the hash list.
>>
>> Cc: David S. Miller <davem@davemloft.net>
>> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
>
> If you are going to do this, please add ASSERT_RTNL() to these two locations
> at the same time.
>

OK, makes sense. I will send v2.