netns: make nsid_lock per net

The spinlock is used to protect netns_ids which is per net,
so there is no need to use a global spinlock.

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 3f850ac..72eb237 100644 (file)
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -58,6 +58,7 @@ struct net {
        struct list_head        exit_list;      /* Use only net_mutex */
 
        struct user_namespace   *user_ns;       /* Owning user namespace */
+       spinlock_t              nsid_lock;
        struct idr              netns_ids;
 
        struct ns_common        ns;

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index d2f42da..2c2eb1b 100644 (file)
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -28,7 +28,6 @@
 static LIST_HEAD(pernet_list);
 static struct list_head *first_device = &pernet_list;
 DEFINE_MUTEX(net_mutex);
-static DEFINE_SPINLOCK(nsid_lock);
 
 LIST_HEAD(net_namespace_list);
 EXPORT_SYMBOL_GPL(net_namespace_list);
@@ -218,10 +217,10 @@ int peernet2id_alloc(struct net *net, struct net *peer)
        bool alloc;
        int id;
 
-       spin_lock_irqsave(&nsid_lock, flags);
+       spin_lock_irqsave(&net->nsid_lock, flags);
        alloc = atomic_read(&peer->count) == 0 ? false : true;
        id = __peernet2id_alloc(net, peer, &alloc);
-       spin_unlock_irqrestore(&nsid_lock, flags);
+       spin_unlock_irqrestore(&net->nsid_lock, flags);
        if (alloc && id >= 0)
                rtnl_net_notifyid(net, RTM_NEWNSID, id);
        return id;
@@ -234,9 +233,9 @@ int peernet2id(struct net *net, struct net *peer)
        unsigned long flags;
        int id;
 
-       spin_lock_irqsave(&nsid_lock, flags);
+       spin_lock_irqsave(&net->nsid_lock, flags);
        id = __peernet2id(net, peer);
-       spin_unlock_irqrestore(&nsid_lock, flags);
+       spin_unlock_irqrestore(&net->nsid_lock, flags);
        return id;
 }
 
@@ -257,11 +256,11 @@ struct net *get_net_ns_by_id(struct net *net, int id)
                return NULL;
 
        rcu_read_lock();
-       spin_lock_irqsave(&nsid_lock, flags);
+       spin_lock_irqsave(&net->nsid_lock, flags);
        peer = idr_find(&net->netns_ids, id);
        if (peer)
                get_net(peer);
-       spin_unlock_irqrestore(&nsid_lock, flags);
+       spin_unlock_irqrestore(&net->nsid_lock, flags);
        rcu_read_unlock();
 
        return peer;
@@ -282,6 +281,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
        net->dev_base_seq = 1;
        net->user_ns = user_ns;
        idr_init(&net->netns_ids);
+       spin_lock_init(&net->nsid_lock);
 
        list_for_each_entry(ops, &pernet_list, list) {
                error = ops_init(ops, net);
@@ -404,17 +404,17 @@ static void cleanup_net(struct work_struct *work)
                for_each_net(tmp) {
                        int id;
 
-                       spin_lock_irq(&nsid_lock);
+                       spin_lock_irq(&tmp->nsid_lock);
                        id = __peernet2id(tmp, net);
                        if (id >= 0)
                                idr_remove(&tmp->netns_ids, id);
-                       spin_unlock_irq(&nsid_lock);
+                       spin_unlock_irq(&tmp->nsid_lock);
                        if (id >= 0)
                                rtnl_net_notifyid(tmp, RTM_DELNSID, id);
                }
-               spin_lock_irq(&nsid_lock);
+               spin_lock_irq(&net->nsid_lock);
                idr_destroy(&net->netns_ids);
-               spin_unlock_irq(&nsid_lock);
+               spin_unlock_irq(&net->nsid_lock);
 
        }
        rtnl_unlock();
@@ -563,15 +563,15 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh)
        if (IS_ERR(peer))
                return PTR_ERR(peer);
 
-       spin_lock_irqsave(&nsid_lock, flags);
+       spin_lock_irqsave(&net->nsid_lock, flags);
        if (__peernet2id(net, peer) >= 0) {
-               spin_unlock_irqrestore(&nsid_lock, flags);
+               spin_unlock_irqrestore(&net->nsid_lock, flags);
                err = -EEXIST;
                goto out;
        }
 
        err = alloc_netid(net, peer, nsid);
-       spin_unlock_irqrestore(&nsid_lock, flags);
+       spin_unlock_irqrestore(&net->nsid_lock, flags);
        if (err >= 0) {
                rtnl_net_notifyid(net, RTM_NEWNSID, err);
                err = 0;
@@ -695,9 +695,9 @@ static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
        };
        unsigned long flags;
 
-       spin_lock_irqsave(&nsid_lock, flags);
+       spin_lock_irqsave(&net->nsid_lock, flags);
        idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
-       spin_unlock_irqrestore(&nsid_lock, flags);
+       spin_unlock_irqrestore(&net->nsid_lock, flags);
 
        cb->args[0] = net_cb.idx;
        return skb->len;