Phonet: convert bound sockets hash list to RCU
This gets rid of the last spinlock in the Phonet stack proper.
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index b1adafa..8c5bfce 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -52,7 +52,7 @@
static struct {
struct hlist_head hlist[PN_HASHSIZE];
- spinlock_t lock;
+ struct mutex lock;
} pnsocks;
void __init pn_sock_init(void)
@@ -61,7 +61,7 @@
for (i = 0; i < PN_HASHSIZE; i++)
INIT_HLIST_HEAD(pnsocks.hlist + i);
- spin_lock_init(&pnsocks.lock);
+ mutex_init(&pnsocks.lock);
}
static struct hlist_head *pn_hash_list(u16 obj)
@@ -82,9 +82,8 @@
u8 res = spn->spn_resource;
struct hlist_head *hlist = pn_hash_list(obj);
- spin_lock_bh(&pnsocks.lock);
-
- sk_for_each(sknode, node, hlist) {
+ rcu_read_lock();
+ sk_for_each_rcu(sknode, node, hlist) {
struct pn_sock *pn = pn_sk(sknode);
BUG_ON(!pn->sobject); /* unbound socket */
@@ -107,8 +106,7 @@
sock_hold(sknode);
break;
}
-
- spin_unlock_bh(&pnsocks.lock);
+ rcu_read_unlock();
return rval;
}
@@ -119,7 +117,7 @@
struct hlist_head *hlist = pnsocks.hlist;
unsigned h;
- spin_lock(&pnsocks.lock);
+ rcu_read_lock();
for (h = 0; h < PN_HASHSIZE; h++) {
struct hlist_node *node;
struct sock *sknode;
@@ -140,25 +138,26 @@
}
hlist++;
}
- spin_unlock(&pnsocks.lock);
+ rcu_read_unlock();
}
void pn_sock_hash(struct sock *sk)
{
struct hlist_head *hlist = pn_hash_list(pn_sk(sk)->sobject);
- spin_lock_bh(&pnsocks.lock);
- sk_add_node(sk, hlist);
- spin_unlock_bh(&pnsocks.lock);
+ mutex_lock(&pnsocks.lock);
+ sk_add_node_rcu(sk, hlist);
+ mutex_unlock(&pnsocks.lock);
}
EXPORT_SYMBOL(pn_sock_hash);
void pn_sock_unhash(struct sock *sk)
{
- spin_lock_bh(&pnsocks.lock);
- sk_del_node_init(sk);
- spin_unlock_bh(&pnsocks.lock);
+ mutex_lock(&pnsocks.lock);
+ sk_del_node_init_rcu(sk);
+ mutex_unlock(&pnsocks.lock);
pn_sock_unbind_all_res(sk);
+ synchronize_rcu();
}
EXPORT_SYMBOL(pn_sock_unhash);
@@ -548,7 +547,7 @@
unsigned h;
for (h = 0; h < PN_HASHSIZE; h++) {
- sk_for_each(sknode, node, hlist) {
+ sk_for_each_rcu(sknode, node, hlist) {
if (!net_eq(net, sock_net(sknode)))
continue;
if (!pos)
@@ -572,9 +571,9 @@
}
static void *pn_sock_seq_start(struct seq_file *seq, loff_t *pos)
- __acquires(pnsocks.lock)
+ __acquires(rcu)
{
- spin_lock_bh(&pnsocks.lock);
+ rcu_read_lock();
return *pos ? pn_sock_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}
@@ -591,9 +590,9 @@
}
static void pn_sock_seq_stop(struct seq_file *seq, void *v)
- __releases(pnsocks.lock)
+ __releases(rcu)
{
- spin_unlock_bh(&pnsocks.lock);
+ rcu_read_unlock();
}
static int pn_sock_seq_show(struct seq_file *seq, void *v)
@@ -721,13 +720,11 @@
}
mutex_unlock(&resource_mutex);
- if (match == 0)
- return;
- synchronize_rcu();
while (match > 0) {
- sock_put(sk);
+ __sock_put(sk);
match--;
}
+ /* Caller is responsible for RCU sync before final sock_put() */
}
#ifdef CONFIG_PROC_FS