af_key: locking change
Get rid of custom locking that was using wait queue, lock, and atomic
to basically build a queued mutex. Use RCU for read side.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/key/af_key.c b/net/key/af_key.c
index a20d2fa..da2fe5f 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -41,9 +41,7 @@
struct hlist_head table;
atomic_t socks_nr;
};
-static DECLARE_WAIT_QUEUE_HEAD(pfkey_table_wait);
-static DEFINE_RWLOCK(pfkey_table_lock);
-static atomic_t pfkey_table_users = ATOMIC_INIT(0);
+static DEFINE_MUTEX(pfkey_mutex);
struct pfkey_sock {
/* struct sock must be the first member of struct pfkey_sock */
@@ -108,50 +106,6 @@
atomic_dec(&net_pfkey->socks_nr);
}
-static void pfkey_table_grab(void)
-{
- write_lock_bh(&pfkey_table_lock);
-
- if (atomic_read(&pfkey_table_users)) {
- DECLARE_WAITQUEUE(wait, current);
-
- add_wait_queue_exclusive(&pfkey_table_wait, &wait);
- for(;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (atomic_read(&pfkey_table_users) == 0)
- break;
- write_unlock_bh(&pfkey_table_lock);
- schedule();
- write_lock_bh(&pfkey_table_lock);
- }
-
- __set_current_state(TASK_RUNNING);
- remove_wait_queue(&pfkey_table_wait, &wait);
- }
-}
-
-static __inline__ void pfkey_table_ungrab(void)
-{
- write_unlock_bh(&pfkey_table_lock);
- wake_up(&pfkey_table_wait);
-}
-
-static __inline__ void pfkey_lock_table(void)
-{
- /* read_lock() synchronizes us to pfkey_table_grab */
-
- read_lock(&pfkey_table_lock);
- atomic_inc(&pfkey_table_users);
- read_unlock(&pfkey_table_lock);
-}
-
-static __inline__ void pfkey_unlock_table(void)
-{
- if (atomic_dec_and_test(&pfkey_table_users))
- wake_up(&pfkey_table_wait);
-}
-
-
static const struct proto_ops pfkey_ops;
static void pfkey_insert(struct sock *sk)
@@ -159,16 +113,16 @@
struct net *net = sock_net(sk);
struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);
- pfkey_table_grab();
- sk_add_node(sk, &net_pfkey->table);
- pfkey_table_ungrab();
+ mutex_lock(&pfkey_mutex);
+ sk_add_node_rcu(sk, &net_pfkey->table);
+ mutex_unlock(&pfkey_mutex);
}
static void pfkey_remove(struct sock *sk)
{
- pfkey_table_grab();
- sk_del_node_init(sk);
- pfkey_table_ungrab();
+ mutex_lock(&pfkey_mutex);
+ sk_del_node_init_rcu(sk);
+ mutex_unlock(&pfkey_mutex);
}
static struct proto key_proto = {
@@ -223,6 +177,8 @@
sock_orphan(sk);
sock->sk = NULL;
skb_queue_purge(&sk->sk_write_queue);
+
+ synchronize_rcu();
sock_put(sk);
return 0;
@@ -277,8 +233,8 @@
if (!skb)
return -ENOMEM;
- pfkey_lock_table();
- sk_for_each(sk, node, &net_pfkey->table) {
+ rcu_read_lock();
+ sk_for_each_rcu(sk, node, &net_pfkey->table) {
struct pfkey_sock *pfk = pfkey_sk(sk);
int err2;
@@ -309,7 +265,7 @@
if ((broadcast_flags & BROADCAST_REGISTERED) && err)
err = err2;
}
- pfkey_unlock_table();
+ rcu_read_unlock();
if (one_sk != NULL)
err = pfkey_broadcast_one(skb, &skb2, allocation, one_sk);
@@ -3702,8 +3658,8 @@
struct net *net = seq_file_net(f);
struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);
- read_lock(&pfkey_table_lock);
- return seq_hlist_start_head(&net_pfkey->table, *ppos);
+ rcu_read_lock();
+ return seq_hlist_start_head_rcu(&net_pfkey->table, *ppos);
}
static void *pfkey_seq_next(struct seq_file *f, void *v, loff_t *ppos)
@@ -3711,12 +3667,12 @@
struct net *net = seq_file_net(f);
struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);
- return seq_hlist_next(v, &net_pfkey->table, ppos);
+ return seq_hlist_next_rcu(v, &net_pfkey->table, ppos);
}
static void pfkey_seq_stop(struct seq_file *f, void *v)
{
- read_unlock(&pfkey_table_lock);
+ rcu_read_unlock();
}
static const struct seq_operations pfkey_seq_ops = {