Phonet: convert devices list to RCU

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/phonet/pn_dev.h b/include/net/phonet/pn_dev.h
index afa7def..d7b989c 100644 (file)
--- 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 d5ad794..d87388c 100644 (file)
--- 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 (file)
--- 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;