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Date: Tue, 17 Nov 2009 15:02:36 +0200
From: Rémi Denis-Courmont <remi@...lab.net>
To: netdev@...r.kernel.org
Cc: Rémi Denis-Courmont
<remi.denis-courmont@...ia.com>
Subject: [RFC] [PATCH net-next] Phonet: convert devices list to RCU
From: Rémi Denis-Courmont <remi.denis-courmont@...ia.com>
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@...ia.com>
---
include/net/phonet/pn_dev.h | 2 +-
net/phonet/pn_dev.c | 63 ++++++++++++++++++++++++++++---------------
net/phonet/pn_netlink.c | 6 ++--
3 files changed, 45 insertions(+), 26 deletions(-)
diff --git a/include/net/phonet/pn_dev.h b/include/net/phonet/pn_dev.h
index afa7def..d7b989c 100644
--- a/include/net/phonet/pn_dev.h
+++ b/include/net/phonet/pn_dev.h
@@ -25,7 +25,7 @@
struct phonet_device_list {
struct list_head list;
- spinlock_t lock;
+ struct mutex lock;
};
struct phonet_device_list *phonet_device_list(struct net *net);
diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c
index 3287f8f..3d9608f 100644
--- a/net/phonet/pn_dev.c
+++ b/net/phonet/pn_dev.c
@@ -61,7 +61,8 @@ static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
pnd->netdev = dev;
bitmap_zero(pnd->addrs, 64);
- list_add(&pnd->list, &pndevs->list);
+ BUG_ON(!mutex_is_locked(&pndevs->lock));
+ list_add_rcu(&pnd->list, &pndevs->list);
return pnd;
}
@@ -70,6 +71,7 @@ static struct phonet_device *__phonet_get(struct net_device *dev)
struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
struct phonet_device *pnd;
+ BUG_ON(!mutex_is_locked(&pndevs->lock));
list_for_each_entry(pnd, &pndevs->list, list) {
if (pnd->netdev == dev)
return pnd;
@@ -77,6 +79,18 @@ static struct phonet_device *__phonet_get(struct net_device *dev)
return NULL;
}
+static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
+{
+ struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
+ struct phonet_device *pnd;
+
+ list_for_each_entry_rcu(pnd, &pndevs->list, list) {
+ if (pnd->netdev == dev)
+ return pnd;
+ }
+ return NULL;
+}
+
static void phonet_device_destroy(struct net_device *dev)
{
struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
@@ -84,11 +98,11 @@ static void phonet_device_destroy(struct net_device *dev)
ASSERT_RTNL();
- spin_lock_bh(&pndevs->lock);
+ mutex_lock(&pndevs->lock);
pnd = __phonet_get(dev);
if (pnd)
- list_del(&pnd->list);
- spin_unlock_bh(&pndevs->lock);
+ list_del_rcu(&pnd->list);
+ mutex_unlock(&pndevs->lock);
if (pnd) {
u8 addr;
@@ -106,8 +120,8 @@ struct net_device *phonet_device_get(struct net *net)
struct phonet_device *pnd;
struct net_device *dev = NULL;
- spin_lock_bh(&pndevs->lock);
- list_for_each_entry(pnd, &pndevs->list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pnd, &pndevs->list, list) {
dev = pnd->netdev;
BUG_ON(!dev);
@@ -118,7 +132,7 @@ struct net_device *phonet_device_get(struct net *net)
}
if (dev)
dev_hold(dev);
- spin_unlock_bh(&pndevs->lock);
+ rcu_read_unlock();
return dev;
}
@@ -128,7 +142,7 @@ int phonet_address_add(struct net_device *dev, u8 addr)
struct phonet_device *pnd;
int err = 0;
- spin_lock_bh(&pndevs->lock);
+ mutex_lock(&pndevs->lock);
/* Find or create Phonet-specific device data */
pnd = __phonet_get(dev);
if (pnd == NULL)
@@ -137,7 +151,7 @@ int phonet_address_add(struct net_device *dev, u8 addr)
err = -ENOMEM;
else if (test_and_set_bit(addr >> 2, pnd->addrs))
err = -EEXIST;
- spin_unlock_bh(&pndevs->lock);
+ mutex_unlock(&pndevs->lock);
return err;
}
@@ -147,27 +161,32 @@ int phonet_address_del(struct net_device *dev, u8 addr)
struct phonet_device *pnd;
int err = 0;
- spin_lock_bh(&pndevs->lock);
+ mutex_lock(&pndevs->lock);
pnd = __phonet_get(dev);
- if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs))
+ if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
err = -EADDRNOTAVAIL;
- else if (bitmap_empty(pnd->addrs, 64)) {
- list_del(&pnd->list);
+ pnd = NULL;
+ } else if (bitmap_empty(pnd->addrs, 64))
+ list_del_rcu(&pnd->list);
+ else
+ pnd = NULL;
+ mutex_unlock(&pndevs->lock);
+
+ if (pnd) {
+ synchronize_rcu();
kfree(pnd);
}
- spin_unlock_bh(&pndevs->lock);
return err;
}
/* Gets a source address toward a destination, through a interface. */
u8 phonet_address_get(struct net_device *dev, u8 daddr)
{
- struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
struct phonet_device *pnd;
u8 saddr;
- spin_lock_bh(&pndevs->lock);
- pnd = __phonet_get(dev);
+ rcu_read_lock();
+ pnd = __phonet_get_rcu(dev);
if (pnd) {
BUG_ON(bitmap_empty(pnd->addrs, 64));
@@ -178,7 +197,7 @@ u8 phonet_address_get(struct net_device *dev, u8 daddr)
saddr = find_first_bit(pnd->addrs, 64) << 2;
} else
saddr = PN_NO_ADDR;
- spin_unlock_bh(&pndevs->lock);
+ rcu_read_unlock();
if (saddr == PN_NO_ADDR) {
/* Fallback to another device */
@@ -200,8 +219,8 @@ int phonet_address_lookup(struct net *net, u8 addr)
struct phonet_device *pnd;
int err = -EADDRNOTAVAIL;
- spin_lock_bh(&pndevs->lock);
- list_for_each_entry(pnd, &pndevs->list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pnd, &pndevs->list, list) {
/* Don't allow unregistering devices! */
if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
((pnd->netdev->flags & IFF_UP)) != IFF_UP)
@@ -213,7 +232,7 @@ int phonet_address_lookup(struct net *net, u8 addr)
}
}
found:
- spin_unlock_bh(&pndevs->lock);
+ rcu_read_unlock();
return err;
}
@@ -304,7 +323,7 @@ static int phonet_init_net(struct net *net)
}
INIT_LIST_HEAD(&pnn->pndevs.list);
- spin_lock_init(&pnn->pndevs.lock);
+ mutex_init(&pnn->pndevs.lock);
mutex_init(&pnn->routes.lock);
net_assign_generic(net, phonet_net_id, pnn);
return 0;
diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c
index 609e509..2e6c7eb 100644
--- a/net/phonet/pn_netlink.c
+++ b/net/phonet/pn_netlink.c
@@ -131,8 +131,8 @@ static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
int addr_idx = 0, addr_start_idx = cb->args[1];
pndevs = phonet_device_list(sock_net(skb->sk));
- spin_lock_bh(&pndevs->lock);
- list_for_each_entry(pnd, &pndevs->list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pnd, &pndevs->list, list) {
u8 addr;
if (dev_idx > dev_start_idx)
@@ -154,7 +154,7 @@ static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
}
out:
- spin_unlock_bh(&pndevs->lock);
+ rcu_read_unlock();
cb->args[0] = dev_idx;
cb->args[1] = addr_idx;
--
1.6.3.3
--
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