From c2355e1ab910278a94d487b78590ee3c8eecd08a Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Wed, 13 Oct 2010 16:01:49 +0000 Subject: [PATCH] bonding: Fix bonding drivers improper modification of netpoll structure The bonding driver currently modifies the netpoll structure in its xmit path while sending frames from netpoll. This is racy, as other cpus can access the netpoll structure in parallel. Since the bonding driver points np->dev to a slave device, other cpus can inadvertently attempt to send data directly to slave devices, leading to improper locking with the bonding master, lost frames, and deadlocks. This patch fixes that up. This patch also removes the real_dev pointer from the netpoll structure as that data is really only used by bonding in the poll_controller, and we can emulate its behavior by check each slave for IS_UP. Signed-off-by: Neil Horman Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 15 +++++++++------ include/linux/netpoll.h | 9 +++++++-- net/core/netpoll.c | 6 +++--- 3 files changed, 19 insertions(+), 11 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 7703d35de65d..813cc2f8edd6 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -449,11 +449,9 @@ int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, if (unlikely(bond->dev->priv_flags & IFF_IN_NETPOLL)) { struct netpoll *np = bond->dev->npinfo->netpoll; slave_dev->npinfo = bond->dev->npinfo; - np->real_dev = np->dev = skb->dev; slave_dev->priv_flags |= IFF_IN_NETPOLL; - netpoll_send_skb(np, skb); + netpoll_send_skb_on_dev(np, skb, slave_dev); slave_dev->priv_flags &= ~IFF_IN_NETPOLL; - np->dev = bond->dev; } else #endif dev_queue_xmit(skb); @@ -1332,9 +1330,14 @@ static bool slaves_support_netpoll(struct net_device *bond_dev) static void bond_poll_controller(struct net_device *bond_dev) { - struct net_device *dev = bond_dev->npinfo->netpoll->real_dev; - if (dev != bond_dev) - netpoll_poll_dev(dev); + struct bonding *bond = netdev_priv(bond_dev); + struct slave *slave; + int i; + + bond_for_each_slave(bond, slave, i) { + if (slave->dev && IS_UP(slave->dev)) + netpoll_poll_dev(slave->dev); + } } static void bond_netpoll_cleanup(struct net_device *bond_dev) diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 50d8009be86c..79358bb712c6 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -14,7 +14,6 @@ struct netpoll { struct net_device *dev; - struct net_device *real_dev; char dev_name[IFNAMSIZ]; const char *name; void (*rx_hook)(struct netpoll *, int, char *, int); @@ -53,7 +52,13 @@ void netpoll_set_trap(int trap); void __netpoll_cleanup(struct netpoll *np); void netpoll_cleanup(struct netpoll *np); int __netpoll_rx(struct sk_buff *skb); -void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb); +void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, + struct net_device *dev); +static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) +{ + netpoll_send_skb_on_dev(np, skb, np->dev); +} + #ifdef CONFIG_NETPOLL diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 537e01afd81b..4e98ffac3af0 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -288,11 +288,11 @@ static int netpoll_owner_active(struct net_device *dev) return 0; } -void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) +void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, + struct net_device *dev) { int status = NETDEV_TX_BUSY; unsigned long tries; - struct net_device *dev = np->dev; const struct net_device_ops *ops = dev->netdev_ops; /* It is up to the caller to keep npinfo alive. */ struct netpoll_info *npinfo = np->dev->npinfo; @@ -346,7 +346,7 @@ void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) schedule_delayed_work(&npinfo->tx_work,0); } } -EXPORT_SYMBOL(netpoll_send_skb); +EXPORT_SYMBOL(netpoll_send_skb_on_dev); void netpoll_send_udp(struct netpoll *np, const char *msg, int len) {