bonding: improve link-status update in mii-monitoring

The primary issue is that mii-inspect phase updates link-state and
expects changes to be committed during the mii-commit phase. After
the inspect phase if it fails to acquire rtnl-mutex, the commit
phase (bond_mii_commit) doesn't get to run. This partially updated
state stays and makes the internal-state inconsistent.

e.g. setup bond0 => slaves: eth1, eth2
eth1 goes DOWN -> UP
   mii_monitor()
	mii-inspect()
	    bond_set_slave_link_state(eth1, UP, DontNotify)
	rtnl_trylock() <- fails!

Next mii-monitor round
eth1: No change
   mii_monitor()
	mii-inspect()
	    eth1->link == current-status (ethtool_ops->get_link)
	    no-change-detected

End result:
    eth1:
      Link = BOND_LINK_UP
      Speed = 0xfffff  [SpeedUnknown]
      Duplex = 0xff    [DuplexUnknown]

This doesn't always happen but for some unlucky machines in a large set
of machines it creates problems.

The fix for this is to avoid making changes during inspect phase and
postpone them until acquiring the rtnl-mutex / invoking commit phase.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ba934020dfaa084acb9930a560771ad5f1b09556..85999e479916feaea3708c3b5d75c3c4a6647464 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2033,8 +2033,7 @@ static int bond_miimon_inspect(struct bonding *bond)
                        if (link_state)
                                continue;
 
-                       bond_set_slave_link_state(slave, BOND_LINK_FAIL,
-                                                 BOND_SLAVE_NOTIFY_LATER);
+                       bond_propose_link_state(slave, BOND_LINK_FAIL);
                        slave->delay = bond->params.downdelay;
                        if (slave->delay) {
                                netdev_info(bond->dev, "link status down for %sinterface %s, disabling it in %d ms\n",
@@ -2049,8 +2048,7 @@ static int bond_miimon_inspect(struct bonding *bond)
                case BOND_LINK_FAIL:
                        if (link_state) {
                                /* recovered before downdelay expired */
-                               bond_set_slave_link_state(slave, BOND_LINK_UP,
-                                                         BOND_SLAVE_NOTIFY_LATER);
+                               bond_propose_link_state(slave, BOND_LINK_UP);
                                slave->last_link_up = jiffies;
                                netdev_info(bond->dev, "link status up again after %d ms for interface %s\n",
                                            (bond->params.downdelay - slave->delay) *
@@ -2072,8 +2070,7 @@ static int bond_miimon_inspect(struct bonding *bond)
                        if (!link_state)
                                continue;
 
-                       bond_set_slave_link_state(slave, BOND_LINK_BACK,
-                                                 BOND_SLAVE_NOTIFY_LATER);
+                       bond_propose_link_state(slave, BOND_LINK_BACK);
                        slave->delay = bond->params.updelay;
 
                        if (slave->delay) {
@@ -2086,9 +2083,7 @@ static int bond_miimon_inspect(struct bonding *bond)
                        /*FALLTHRU*/
                case BOND_LINK_BACK:
                        if (!link_state) {
-                               bond_set_slave_link_state(slave,
-                                                         BOND_LINK_DOWN,
-                                                         BOND_SLAVE_NOTIFY_LATER);
+                               bond_propose_link_state(slave, BOND_LINK_DOWN);
                                netdev_info(bond->dev, "link status down again after %d ms for interface %s\n",
                                            (bond->params.updelay - slave->delay) *
                                            bond->params.miimon,
@@ -2225,6 +2220,8 @@ static void bond_mii_monitor(struct work_struct *work)
                                            mii_work.work);
        bool should_notify_peers = false;
        unsigned long delay;
+       struct slave *slave;
+       struct list_head *iter;
 
        delay = msecs_to_jiffies(bond->params.miimon);
 
@@ -2245,6 +2242,9 @@ static void bond_mii_monitor(struct work_struct *work)
                        goto re_arm;
                }
 
+               bond_for_each_slave(bond, slave, iter) {
+                       bond_commit_link_state(slave, BOND_SLAVE_NOTIFY_LATER);
+               }
                bond_miimon_commit(bond);
 
                rtnl_unlock();  /* might sleep, hold no other locks */