Commit 808f5114 authored by stephen hemminger's avatar stephen hemminger Committed by David S. Miller
Browse files

packet: convert socket list to RCU (v3)



Convert AF_PACKET to use RCU, eliminating one more reader/writer lock.

There is no need for a real sk_del_node_init_rcu(), because sk_del_node_init
is doing the equivalent thing to hlst_del_init_rcu already; but added
some comments to try and make that obvious.
Signed-off-by: default avatarStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1cc52327
......@@ -4,11 +4,11 @@
#ifndef __NETNS_PACKET_H__
#define __NETNS_PACKET_H__
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
struct netns_packet {
rwlock_t sklist_lock;
spinlock_t sklist_lock;
struct hlist_head sklist;
};
......
......@@ -381,6 +381,7 @@ static __inline__ void __sk_del_node(struct sock *sk)
__hlist_del(&sk->sk_node);
}
/* NB: equivalent to hlist_del_init_rcu */
static __inline__ int __sk_del_node_init(struct sock *sk)
{
if (sk_hashed(sk)) {
......@@ -421,6 +422,7 @@ static __inline__ int sk_del_node_init(struct sock *sk)
}
return rc;
}
#define sk_del_node_init_rcu(sk) sk_del_node_init(sk)
static __inline__ int __sk_nulls_del_node_init_rcu(struct sock *sk)
{
......@@ -454,6 +456,12 @@ static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
__sk_add_node(sk, list);
}
static __inline__ void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
{
sock_hold(sk);
hlist_add_head_rcu(&sk->sk_node, list);
}
static __inline__ void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
{
hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
......@@ -478,6 +486,8 @@ static __inline__ void sk_add_bind_node(struct sock *sk,
#define sk_for_each(__sk, node, list) \
hlist_for_each_entry(__sk, node, list, sk_node)
#define sk_for_each_rcu(__sk, node, list) \
hlist_for_each_entry_rcu(__sk, node, list, sk_node)
#define sk_nulls_for_each(__sk, node, list) \
hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
#define sk_nulls_for_each_rcu(__sk, node, list) \
......
......@@ -1262,24 +1262,22 @@ static int packet_release(struct socket *sock)
net = sock_net(sk);
po = pkt_sk(sk);
write_lock_bh(&net->packet.sklist_lock);
sk_del_node_init(sk);
spin_lock_bh(&net->packet.sklist_lock);
sk_del_node_init_rcu(sk);
sock_prot_inuse_add(net, sk->sk_prot, -1);
write_unlock_bh(&net->packet.sklist_lock);
/*
* Unhook packet receive handler.
*/
spin_unlock_bh(&net->packet.sklist_lock);
spin_lock(&po->bind_lock);
if (po->running) {
/*
* Remove the protocol hook
* Remove from protocol table
*/
dev_remove_pack(&po->prot_hook);
po->running = 0;
po->num = 0;
__dev_remove_pack(&po->prot_hook);
__sock_put(sk);
}
spin_unlock(&po->bind_lock);
packet_flush_mclist(sk);
......@@ -1291,10 +1289,10 @@ static int packet_release(struct socket *sock)
if (po->tx_ring.pg_vec)
packet_set_ring(sk, &req, 1, 1);
synchronize_net();
/*
* Now the socket is dead. No more input will appear.
*/
sock_orphan(sk);
sock->sk = NULL;
......@@ -1478,10 +1476,11 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
po->running = 1;
}
write_lock_bh(&net->packet.sklist_lock);
sk_add_node(sk, &net->packet.sklist);
spin_lock_bh(&net->packet.sklist_lock);
sk_add_node_rcu(sk, &net->packet.sklist);
sock_prot_inuse_add(net, &packet_proto, 1);
write_unlock_bh(&net->packet.sklist_lock);
spin_unlock_bh(&net->packet.sklist_lock);
return 0;
out:
return err;
......@@ -2075,8 +2074,8 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
struct net_device *dev = data;
struct net *net = dev_net(dev);
read_lock(&net->packet.sklist_lock);
sk_for_each(sk, node, &net->packet.sklist) {
rcu_read_lock();
sk_for_each_rcu(sk, node, &net->packet.sklist) {
struct packet_sock *po = pkt_sk(sk);
switch (msg) {
......@@ -2104,18 +2103,19 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
}
break;
case NETDEV_UP:
spin_lock(&po->bind_lock);
if (dev->ifindex == po->ifindex && po->num &&
!po->running) {
dev_add_pack(&po->prot_hook);
sock_hold(sk);
po->running = 1;
if (dev->ifindex == po->ifindex) {
spin_lock(&po->bind_lock);
if (po->num && !po->running) {
dev_add_pack(&po->prot_hook);
sock_hold(sk);
po->running = 1;
}
spin_unlock(&po->bind_lock);
}
spin_unlock(&po->bind_lock);
break;
}
}
read_unlock(&net->packet.sklist_lock);
rcu_read_unlock();
return NOTIFY_DONE;
}
......@@ -2512,24 +2512,24 @@ static struct notifier_block packet_netdev_notifier = {
#ifdef CONFIG_PROC_FS
static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(seq_file_net(seq)->packet.sklist_lock)
__acquires(RCU)
{
struct net *net = seq_file_net(seq);
read_lock(&net->packet.sklist_lock);
return seq_hlist_start_head(&net->packet.sklist, *pos);
rcu_read_lock();
return seq_hlist_start_head_rcu(&net->packet.sklist, *pos);
}
static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct net *net = seq_file_net(seq);
return seq_hlist_next(v, &net->packet.sklist, pos);
return seq_hlist_next_rcu(v, &net->packet.sklist, pos);
}
static void packet_seq_stop(struct seq_file *seq, void *v)
__releases(seq_file_net(seq)->packet.sklist_lock)
__releases(RCU)
{
struct net *net = seq_file_net(seq);
read_unlock(&net->packet.sklist_lock);
rcu_read_unlock();
}
static int packet_seq_show(struct seq_file *seq, void *v)
......@@ -2581,7 +2581,7 @@ static const struct file_operations packet_seq_fops = {
static int __net_init packet_net_init(struct net *net)
{
rwlock_init(&net->packet.sklist_lock);
spin_lock_init(&net->packet.sklist_lock);
INIT_HLIST_HEAD(&net->packet.sklist);
if (!proc_net_fops_create(net, "packet", 0, &packet_seq_fops))
......
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