Revert "Merge branch 'bonding_monitor_locking'"

This reverts commit 4d961a101e032b4bf223b279b4b35bc77576f5a8, reversing
changes made to a00f6fcc7d0c62a91768d9c4ccba4c7d64fbbce3.

Revert bond locking changes, they cause regressions and Veaceslav Falico
doesn't like how the commit messages were done at all.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 69 insertions, 31 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 535570ea8bbc..a141f406cb98 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2118,29 +2118,49 @@ void bond_mii_monitor(struct work_struct *work)
         struct bonding *bond = container_of(work, struct bonding,
                                             mii_work.work);
         bool should_notify_peers = false;
+        unsigned long delay;
 
-        if (!rtnl_trylock())
-                goto re_arm;
+        read_lock(&bond->lock);
 
-        if (!bond_has_slaves(bond)) {
-                rtnl_unlock();
+        delay = msecs_to_jiffies(bond->params.miimon);
+
+        if (!bond_has_slaves(bond))
                 goto re_arm;
-        }
 
         should_notify_peers = bond_should_notify_peers(bond);
 
-        if (bond_miimon_inspect(bond))
-                bond_miimon_commit(bond);
+        if (bond_miimon_inspect(bond)) {
+                read_unlock(&bond->lock);
 
-        if (should_notify_peers)
-                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
+                /* Race avoidance with bond_close cancel of workqueue */
+                if (!rtnl_trylock()) {
+                        read_lock(&bond->lock);
+                        delay = 1;
+                        should_notify_peers = false;
+                        goto re_arm;
+                }
 
-        rtnl_unlock();
+                read_lock(&bond->lock);
+
+                bond_miimon_commit(bond);
+
+                read_unlock(&bond->lock);
+                rtnl_unlock();  /* might sleep, hold no other locks */
+                read_lock(&bond->lock);
+        }
 
 re_arm:
         if (bond->params.miimon)
-                queue_delayed_work(bond->wq, &bond->mii_work,
-                                msecs_to_jiffies(bond->params.miimon));
+                queue_delayed_work(bond->wq, &bond->mii_work, delay);
+
+        read_unlock(&bond->lock);
+
+        if (should_notify_peers) {
+                if (!rtnl_trylock())
+                        return;
+                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
+                rtnl_unlock();
+        }
 }
 
 static bool bond_has_this_ip(struct bonding *bond, __be32 ip)
@@ -2396,13 +2416,10 @@ void bond_loadbalance_arp_mon(struct work_struct *work)
         struct list_head *iter;
         int do_failover = 0;
 
-        if (!rtnl_trylock())
-                goto re_arm;
+        read_lock(&bond->lock);
 
-        if (!bond_has_slaves(bond)) {
-                rtnl_unlock();
+        if (!bond_has_slaves(bond))
                 goto re_arm;
-        }
 
         oldcurrent = bond->curr_active_slave;
         /* see if any of the previous devices are up now (i.e. they have
@@ -2484,12 +2501,13 @@ void bond_loadbalance_arp_mon(struct work_struct *work)
                 write_unlock_bh(&bond->curr_slave_lock);
                 unblock_netpoll_tx();
         }
-        rtnl_unlock();
 
 re_arm:
         if (bond->params.arp_interval)
                 queue_delayed_work(bond->wq, &bond->arp_work,
                                    msecs_to_jiffies(bond->params.arp_interval));
+
+        read_unlock(&bond->lock);
 }
 
 /*
@@ -2726,31 +2744,51 @@ void bond_activebackup_arp_mon(struct work_struct *work)
         struct bonding *bond = container_of(work, struct bonding,
                                             arp_work.work);
         bool should_notify_peers = false;
+        int delta_in_ticks;
 
-        if (!rtnl_trylock())
-                goto re_arm;
+        read_lock(&bond->lock);
 
-        if (!bond_has_slaves(bond)) {
-                rtnl_unlock();
+        delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval);
+
+        if (!bond_has_slaves(bond))
                 goto re_arm;
-        }
 
         should_notify_peers = bond_should_notify_peers(bond);
 
-        if (bond_ab_arp_inspect(bond))
-                bond_ab_arp_commit(bond);
+        if (bond_ab_arp_inspect(bond)) {
+                read_unlock(&bond->lock);
 
-        bond_ab_arp_probe(bond);
+                /* Race avoidance with bond_close flush of workqueue */
+                if (!rtnl_trylock()) {
+                        read_lock(&bond->lock);
+                        delta_in_ticks = 1;
+                        should_notify_peers = false;
+                        goto re_arm;
+                }
 
-        if (should_notify_peers)
-                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
+                read_lock(&bond->lock);
 
-        rtnl_unlock();
+                bond_ab_arp_commit(bond);
+
+                read_unlock(&bond->lock);
+                rtnl_unlock();
+                read_lock(&bond->lock);
+        }
+
+        bond_ab_arp_probe(bond);
 
 re_arm:
         if (bond->params.arp_interval)
-                queue_delayed_work(bond->wq, &bond->arp_work,
-                                msecs_to_jiffies(bond->params.arp_interval));
+                queue_delayed_work(bond->wq, &bond->arp_work, delta_in_ticks);
+
+        read_unlock(&bond->lock);
+
+        if (should_notify_peers) {
+                if (!rtnl_trylock())
+                        return;
+                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
+                rtnl_unlock();
+        }
 }
 
 /*-------------------------- netdev event handling --------------------------*/