3 files changed, 80 insertions, 4 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 813cc2f8edd6..b46cb139477d 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -76,6 +76,7 @@
 #include <linux/if_vlan.h>
 #include <linux/if_bonding.h>
 #include <linux/jiffies.h>
+#include <linux/preempt.h>
 #include <net/route.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
@@ -169,6 +170,10 @@ MODULE_PARM_DESC(resend_igmp, "Number of IGMP membership reports to send on link
 
 /*----------------------------- Global variables ----------------------------*/
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+cpumask_var_t netpoll_block_tx;
+#endif
+
 static const char * const version =
         DRV_DESCRIPTION ": v" DRV_VERSION " (" DRV_RELDATE ")\n";
 
@@ -310,6 +315,7 @@ static int bond_del_vlan(struct bonding *bond, unsigned short vlan_id)
 
         pr_debug("bond: %s, vlan id %d\n", bond->dev->name, vlan_id);
 
+        block_netpoll_tx();
         write_lock_bh(&bond->lock);
 
         list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
@@ -344,6 +350,7 @@ static int bond_del_vlan(struct bonding *bond, unsigned short vlan_id)
 
 out:
         write_unlock_bh(&bond->lock);
+        unblock_netpoll_tx();
         return res;
 }
 
@@ -1804,10 +1811,6 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
         bond_set_carrier(bond);
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
-        /*
-         * Netpoll and bonding is broken, make sure it is not initialized
-         * until it is fixed.
-         */
         if (disable_netpoll) {
                 bond_dev->priv_flags |= IFF_DISABLE_NETPOLL;
         } else {
@@ -1892,6 +1895,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
                 return -EINVAL;
         }
 
+        block_netpoll_tx();
         netdev_bonding_change(bond_dev, NETDEV_BONDING_DESLAVE);
         write_lock_bh(&bond->lock);
 
@@ -1901,6 +1905,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
                 pr_info("%s: %s not enslaved\n",
                         bond_dev->name, slave_dev->name);
                 write_unlock_bh(&bond->lock);
+                unblock_netpoll_tx();
                 return -EINVAL;
         }
 
@@ -1994,6 +1999,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
         }
 
         write_unlock_bh(&bond->lock);
+        unblock_netpoll_tx();
 
         /* must do this from outside any spinlocks */
         bond_destroy_slave_symlinks(bond_dev, slave_dev);
@@ -2085,6 +2091,7 @@ static int bond_release_all(struct net_device *bond_dev)
         struct net_device *slave_dev;
         struct sockaddr addr;
 
+        block_netpoll_tx();
         write_lock_bh(&bond->lock);
 
         netif_carrier_off(bond_dev);
@@ -2183,6 +2190,7 @@ static int bond_release_all(struct net_device *bond_dev)
 
 out:
         write_unlock_bh(&bond->lock);
+        unblock_netpoll_tx();
 
         return 0;
 }
@@ -2232,9 +2240,11 @@ static int bond_ioctl_change_active(struct net_device *bond_dev, struct net_devi
             (old_active) &&
             (new_active->link == BOND_LINK_UP) &&
             IS_UP(new_active->dev)) {
+                block_netpoll_tx();
                 write_lock_bh(&bond->curr_slave_lock);
                 bond_change_active_slave(bond, new_active);
                 write_unlock_bh(&bond->curr_slave_lock);
+                unblock_netpoll_tx();
         } else
                 res = -EINVAL;
 
@@ -2466,9 +2476,11 @@ static void bond_miimon_commit(struct bonding *bond)
 
 do_failover:
                 ASSERT_RTNL();
+                block_netpoll_tx();
                 write_lock_bh(&bond->curr_slave_lock);
                 bond_select_active_slave(bond);
                 write_unlock_bh(&bond->curr_slave_lock);
+                unblock_netpoll_tx();
         }
 
         bond_set_carrier(bond);
@@ -2911,11 +2923,13 @@ void bond_loadbalance_arp_mon(struct work_struct *work)
         }
 
         if (do_failover) {
+                block_netpoll_tx();
                 write_lock_bh(&bond->curr_slave_lock);
 
                 bond_select_active_slave(bond);
 
                 write_unlock_bh(&bond->curr_slave_lock);
+                unblock_netpoll_tx();
         }
 
 re_arm:
@@ -3074,9 +3088,11 @@ static void bond_ab_arp_commit(struct bonding *bond, int delta_in_ticks)
 
 do_failover:
                 ASSERT_RTNL();
+                block_netpoll_tx();
                 write_lock_bh(&bond->curr_slave_lock);
                 bond_select_active_slave(bond);
                 write_unlock_bh(&bond->curr_slave_lock);
+                unblock_netpoll_tx();
         }
 
         bond_set_carrier(bond);
@@ -4564,6 +4580,13 @@ static netdev_tx_t bond_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct bonding *bond = netdev_priv(dev);
 
+        /*
+         * If we risk deadlock from transmitting this in the
+         * netpoll path, tell netpoll to queue the frame for later tx
+         */
+        if (is_netpoll_tx_blocked(dev))
+                return NETDEV_TX_BUSY;
+
         if (TX_QUEUE_OVERRIDE(bond->params.mode)) {
                 if (!bond_slave_override(bond, skb))
                         return NETDEV_TX_OK;
@@ -5286,6 +5309,13 @@ static int __init bonding_init(void)
         if (res)
                 goto out;
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        if (!alloc_cpumask_var(&netpoll_block_tx, GFP_KERNEL)) {
+                res = -ENOMEM;
+                goto out;
+        }
+#endif
+
         res = register_pernet_subsys(&bond_net_ops);
         if (res)
                 goto out;
@@ -5304,6 +5334,7 @@ static int __init bonding_init(void)
         if (res)
                 goto err;
 
+
         register_netdevice_notifier(&bond_netdev_notifier);
         register_inetaddr_notifier(&bond_inetaddr_notifier);
         bond_register_ipv6_notifier();
@@ -5313,6 +5344,9 @@ err:
         rtnl_link_unregister(&bond_link_ops);
 err_link:
         unregister_pernet_subsys(&bond_net_ops);
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        free_cpumask_var(netpoll_block_tx);
+#endif
         goto out;
 
 }
@@ -5327,6 +5361,10 @@ static void __exit bonding_exit(void)
 
         rtnl_link_unregister(&bond_link_ops);
         unregister_pernet_subsys(&bond_net_ops);
+
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        free_cpumask_var(netpoll_block_tx);
+#endif
 }
 
 module_init(bonding_init);
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 01b4c3f5d9e7..8fd0174c5380 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1066,6 +1066,7 @@ static ssize_t bonding_store_primary(struct device *d,
 
         if (!rtnl_trylock())
                 return restart_syscall();
+        block_netpoll_tx();
         read_lock(&bond->lock);
         write_lock_bh(&bond->curr_slave_lock);
 
@@ -1101,6 +1102,7 @@ static ssize_t bonding_store_primary(struct device *d,
 out:
         write_unlock_bh(&bond->curr_slave_lock);
         read_unlock(&bond->lock);
+        unblock_netpoll_tx();
         rtnl_unlock();
 
         return count;
@@ -1146,11 +1148,13 @@ static ssize_t bonding_store_primary_reselect(struct device *d,
                 bond->dev->name, pri_reselect_tbl[new_value].modename,
                 new_value);
 
+        block_netpoll_tx();
         read_lock(&bond->lock);
         write_lock_bh(&bond->curr_slave_lock);
         bond_select_active_slave(bond);
         write_unlock_bh(&bond->curr_slave_lock);
         read_unlock(&bond->lock);
+        unblock_netpoll_tx();
 out:
         rtnl_unlock();
         return ret;
@@ -1232,6 +1236,8 @@ static ssize_t bonding_store_active_slave(struct device *d,
 
         if (!rtnl_trylock())
                 return restart_syscall();
+
+        block_netpoll_tx();
         read_lock(&bond->lock);
         write_lock_bh(&bond->curr_slave_lock);
 
@@ -1288,6 +1294,8 @@ static ssize_t bonding_store_active_slave(struct device *d,
  out:
         write_unlock_bh(&bond->curr_slave_lock);
         read_unlock(&bond->lock);
+        unblock_netpoll_tx();
+
         rtnl_unlock();
 
         return count;
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index c15f21347486..2c12a5f812f4 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -19,6 +19,7 @@
 #include <linux/proc_fs.h>
 #include <linux/if_bonding.h>
 #include <linux/kobject.h>
+#include <linux/cpumask.h>
 #include <linux/in6.h>
 #include "bond_3ad.h"
 #include "bond_alb.h"
@@ -117,6 +118,35 @@
                 bond_for_each_slave_from(bond, pos, cnt, (bond)->first_slave)
 
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+extern cpumask_var_t netpoll_block_tx;
+
+static inline void block_netpoll_tx(void)
+{
+        preempt_disable();
+        BUG_ON(cpumask_test_and_set_cpu(smp_processor_id(),
+                                        netpoll_block_tx));
+}
+
+static inline void unblock_netpoll_tx(void)
+{
+        BUG_ON(!cpumask_test_and_clear_cpu(smp_processor_id(),
+                                           netpoll_block_tx));
+        preempt_enable();
+}
+
+static inline int is_netpoll_tx_blocked(struct net_device *dev)
+{
+        if (unlikely(dev->priv_flags & IFF_IN_NETPOLL))
+                return cpumask_test_cpu(smp_processor_id(), netpoll_block_tx);
+        return 0;
+}
+#else
+#define block_netpoll_tx()
+#define unblock_netpoll_tx()
+#define is_netpoll_tx_blocked(dev) (0)
+#endif
+
 struct bond_params {
         int mode;
         int xmit_policy;