ipvlan: Make the addrs_lock be per port

Make the addrs_lock be per port, not per ipvlan dev.

Initial code seems to be written in the assumption,
that any address change must occur under RTNL.
But it is not so for the case of IPv6. So

1) Introduce per-port addrs_lock.

2) It was needed to fix places where it was forgotten
to take lock (ipvlan_open/ipvlan_close)

This appears to be a very minor problem though.
Since it's highly unlikely that ipvlan_add_addr() will
be called on 2 CPU simultaneously. But nevertheless,
this could cause:

1) False-negative of ipvlan_addr_busy(): one interface
iterated through all port->ipvlans + ipvlan->addrs
under some ipvlan spinlock, and another added IP
under its own lock. Though this is only possible
for IPv6, since looks like only ipvlan_addr6_event() can be
called without rtnl_lock.

2) Race since ipvlan_ht_addr_add(port) is called under
different ipvlan->addrs_lock locks

This should not affect performance, since add/remove IP
is a rare situation and spinlock is not taken on fast
paths.

Fixes: 8230819494b3 ("ipvlan: use per device spinlock to protect addrs list updates")
Signed-off-by: Dmitry Skorodumov <skorodumov.dmitry@huawei.com>
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/20260112142417.4039566-2-skorodumov.dmitry@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index 50de3ee204dbc9bf63076b48e0f80222f8c10333..80f84fc87008b39e5c37184cfaa58fc4dda66cc6 100644 (file)
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -69,7 +69,6 @@ struct ipvl_dev {
        DECLARE_BITMAP(mac_filters, IPVLAN_MAC_FILTER_SIZE);
        netdev_features_t       sfeatures;
        u32                     msg_enable;
-       spinlock_t              addrs_lock;
 };
 
 struct ipvl_addr {
@@ -90,6 +89,7 @@ struct ipvl_port {
        struct net_device       *dev;
        possible_net_t          pnet;
        struct hlist_head       hlhead[IPVLAN_HASH_SIZE];
+       spinlock_t              addrs_lock; /* guards hash-table and addrs */
        struct list_head        ipvlans;
        u16                     mode;
        u16                     flags;

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 2efa3ba148aa7efed999dc3c06ccbb787eca92e5..bdb3a46b327c4201938efaf5365e7886a86cee16 100644 (file)
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -107,17 +107,15 @@ void ipvlan_ht_addr_del(struct ipvl_addr *addr)
 struct ipvl_addr *ipvlan_find_addr(const struct ipvl_dev *ipvlan,
                                   const void *iaddr, bool is_v6)
 {
-       struct ipvl_addr *addr, *ret = NULL;
+       struct ipvl_addr *addr;
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(addr, &ipvlan->addrs, anode) {
-               if (addr_equal(is_v6, addr, iaddr)) {
-                       ret = addr;
-                       break;
-               }
+       assert_spin_locked(&ipvlan->port->addrs_lock);
+
+       list_for_each_entry(addr, &ipvlan->addrs, anode) {
+               if (addr_equal(is_v6, addr, iaddr))
+                       return addr;
        }
-       rcu_read_unlock();
-       return ret;
+       return NULL;
 }
 
 bool ipvlan_addr_busy(struct ipvl_port *port, void *iaddr, bool is_v6)

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 660f3db117664e2f3c5f8042739ccb19d781ef9e..baccdad695fdad5bf03bd3f092c0dd16d8ecb406 100644 (file)
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -75,6 +75,7 @@ static int ipvlan_port_create(struct net_device *dev)
        for (idx = 0; idx < IPVLAN_HASH_SIZE; idx++)
                INIT_HLIST_HEAD(&port->hlhead[idx]);
 
+       spin_lock_init(&port->addrs_lock);
        skb_queue_head_init(&port->backlog);
        INIT_WORK(&port->wq, ipvlan_process_multicast);
        ida_init(&port->ida);
@@ -181,6 +182,7 @@ static void ipvlan_uninit(struct net_device *dev)
 static int ipvlan_open(struct net_device *dev)
 {
        struct ipvl_dev *ipvlan = netdev_priv(dev);
+       struct ipvl_port *port = ipvlan->port;
        struct ipvl_addr *addr;
 
        if (ipvlan->port->mode == IPVLAN_MODE_L3 ||
@@ -189,10 +191,10 @@ static int ipvlan_open(struct net_device *dev)
        else
                dev->flags &= ~IFF_NOARP;
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(addr, &ipvlan->addrs, anode)
+       spin_lock_bh(&port->addrs_lock);
+       list_for_each_entry(addr, &ipvlan->addrs, anode)
                ipvlan_ht_addr_add(ipvlan, addr);
-       rcu_read_unlock();
+       spin_unlock_bh(&port->addrs_lock);
 
        return 0;
 }
@@ -206,10 +208,10 @@ static int ipvlan_stop(struct net_device *dev)
        dev_uc_unsync(phy_dev, dev);
        dev_mc_unsync(phy_dev, dev);
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(addr, &ipvlan->addrs, anode)
+       spin_lock_bh(&ipvlan->port->addrs_lock);
+       list_for_each_entry(addr, &ipvlan->addrs, anode)
                ipvlan_ht_addr_del(addr);
-       rcu_read_unlock();
+       spin_unlock_bh(&ipvlan->port->addrs_lock);
 
        return 0;
 }
@@ -579,7 +581,6 @@ int ipvlan_link_new(struct net_device *dev, struct rtnl_newlink_params *params,
        if (!tb[IFLA_MTU])
                ipvlan_adjust_mtu(ipvlan, phy_dev);
        INIT_LIST_HEAD(&ipvlan->addrs);
-       spin_lock_init(&ipvlan->addrs_lock);
 
        /* TODO Probably put random address here to be presented to the
         * world but keep using the physical-dev address for the outgoing
@@ -657,13 +658,13 @@ void ipvlan_link_delete(struct net_device *dev, struct list_head *head)
        struct ipvl_dev *ipvlan = netdev_priv(dev);
        struct ipvl_addr *addr, *next;
 
-       spin_lock_bh(&ipvlan->addrs_lock);
+       spin_lock_bh(&ipvlan->port->addrs_lock);
        list_for_each_entry_safe(addr, next, &ipvlan->addrs, anode) {
                ipvlan_ht_addr_del(addr);
                list_del_rcu(&addr->anode);
                kfree_rcu(addr, rcu);
        }
-       spin_unlock_bh(&ipvlan->addrs_lock);
+       spin_unlock_bh(&ipvlan->port->addrs_lock);
 
        ida_free(&ipvlan->port->ida, dev->dev_id);
        list_del_rcu(&ipvlan->pnode);
@@ -817,6 +818,8 @@ static int ipvlan_add_addr(struct ipvl_dev *ipvlan, void *iaddr, bool is_v6)
 {
        struct ipvl_addr *addr;
 
+       assert_spin_locked(&ipvlan->port->addrs_lock);
+
        addr = kzalloc(sizeof(struct ipvl_addr), GFP_ATOMIC);
        if (!addr)
                return -ENOMEM;
@@ -847,16 +850,16 @@ static void ipvlan_del_addr(struct ipvl_dev *ipvlan, void *iaddr, bool is_v6)
 {
        struct ipvl_addr *addr;
 
-       spin_lock_bh(&ipvlan->addrs_lock);
+       spin_lock_bh(&ipvlan->port->addrs_lock);
        addr = ipvlan_find_addr(ipvlan, iaddr, is_v6);
        if (!addr) {
-               spin_unlock_bh(&ipvlan->addrs_lock);
+               spin_unlock_bh(&ipvlan->port->addrs_lock);
                return;
        }
 
        ipvlan_ht_addr_del(addr);
        list_del_rcu(&addr->anode);
-       spin_unlock_bh(&ipvlan->addrs_lock);
+       spin_unlock_bh(&ipvlan->port->addrs_lock);
        kfree_rcu(addr, rcu);
 }
 
@@ -878,14 +881,14 @@ static int ipvlan_add_addr6(struct ipvl_dev *ipvlan, struct in6_addr *ip6_addr)
 {
        int ret = -EINVAL;
 
-       spin_lock_bh(&ipvlan->addrs_lock);
+       spin_lock_bh(&ipvlan->port->addrs_lock);
        if (ipvlan_addr_busy(ipvlan->port, ip6_addr, true))
                netif_err(ipvlan, ifup, ipvlan->dev,
                          "Failed to add IPv6=%pI6c addr for %s intf\n",
                          ip6_addr, ipvlan->dev->name);
        else
                ret = ipvlan_add_addr(ipvlan, ip6_addr, true);
-       spin_unlock_bh(&ipvlan->addrs_lock);
+       spin_unlock_bh(&ipvlan->port->addrs_lock);
        return ret;
 }
 
@@ -924,21 +927,24 @@ static int ipvlan_addr6_validator_event(struct notifier_block *unused,
        struct in6_validator_info *i6vi = (struct in6_validator_info *)ptr;
        struct net_device *dev = (struct net_device *)i6vi->i6vi_dev->dev;
        struct ipvl_dev *ipvlan = netdev_priv(dev);
+       int ret = NOTIFY_OK;
 
        if (!ipvlan_is_valid_dev(dev))
                return NOTIFY_DONE;
 
        switch (event) {
        case NETDEV_UP:
+               spin_lock_bh(&ipvlan->port->addrs_lock);
                if (ipvlan_addr_busy(ipvlan->port, &i6vi->i6vi_addr, true)) {
                        NL_SET_ERR_MSG(i6vi->extack,
                                       "Address already assigned to an ipvlan device");
-                       return notifier_from_errno(-EADDRINUSE);
+                       ret = notifier_from_errno(-EADDRINUSE);
                }
+               spin_unlock_bh(&ipvlan->port->addrs_lock);
                break;
        }
 
-       return NOTIFY_OK;
+       return ret;
 }
 #endif
 
@@ -946,14 +952,14 @@ static int ipvlan_add_addr4(struct ipvl_dev *ipvlan, struct in_addr *ip4_addr)
 {
        int ret = -EINVAL;
 
-       spin_lock_bh(&ipvlan->addrs_lock);
+       spin_lock_bh(&ipvlan->port->addrs_lock);
        if (ipvlan_addr_busy(ipvlan->port, ip4_addr, false))
                netif_err(ipvlan, ifup, ipvlan->dev,
                          "Failed to add IPv4=%pI4 on %s intf.\n",
                          ip4_addr, ipvlan->dev->name);
        else
                ret = ipvlan_add_addr(ipvlan, ip4_addr, false);
-       spin_unlock_bh(&ipvlan->addrs_lock);
+       spin_unlock_bh(&ipvlan->port->addrs_lock);
        return ret;
 }
 
@@ -995,21 +1001,24 @@ static int ipvlan_addr4_validator_event(struct notifier_block *unused,
        struct in_validator_info *ivi = (struct in_validator_info *)ptr;
        struct net_device *dev = (struct net_device *)ivi->ivi_dev->dev;
        struct ipvl_dev *ipvlan = netdev_priv(dev);
+       int ret = NOTIFY_OK;
 
        if (!ipvlan_is_valid_dev(dev))
                return NOTIFY_DONE;
 
        switch (event) {
        case NETDEV_UP:
+               spin_lock_bh(&ipvlan->port->addrs_lock);
                if (ipvlan_addr_busy(ipvlan->port, &ivi->ivi_addr, false)) {
                        NL_SET_ERR_MSG(ivi->extack,
                                       "Address already assigned to an ipvlan device");
-                       return notifier_from_errno(-EADDRINUSE);
+                       ret = notifier_from_errno(-EADDRINUSE);
                }
+               spin_unlock_bh(&ipvlan->port->addrs_lock);
                break;
        }
 
-       return NOTIFY_OK;
+       return ret;
 }
 
 static struct notifier_block ipvlan_addr4_notifier_block __read_mostly = {