Gitweb:     http://git.kernel.org/linus/c22d7ac844f1cb9c6a5fd20f89ebadc2feef891b
Commit:     c22d7ac844f1cb9c6a5fd20f89ebadc2feef891b
Parent:     e2f5b04563786d4b7d7648868de7e941a0649372
Author:     Andy Gospodarek <andy@greyhouse.net>
AuthorDate: Fri Jun 25 09:50:44 2010 +0000
Committer:  David S. Miller <davem@davemloft.net>
CommitDate: Mon Jun 28 23:54:10 2010 -0700

    bonding: prevent netpoll over bonded interfaces
    
    Support for netpoll over bonded interfaces was added here:
    
    	commit f6dc31a85cd46a959bdd987adad14c3b645e03c1
    	Author: WANG Cong <amwang@redhat.com>
    	Date:   Thu May 6 00:48:51 2010 -0700
    
    	    bonding: make bonding support netpoll
    
    but it is bad enough that we should probably just disable netpoll over
    bonding until some of the locking logic in the bonding driver is changed
    or converted completely to RCU.  Simple actions like changing the active
    slave in active-backup mode will hang the box if a high enough printk
    debugging level is enabled.
    
    Keeping the old code around will be good for anyone that wants to work
    on it (and for after the RCU conversion), so I propose this small patch
    rather than ripping it all out.
    
    Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
    Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/bonding/bond_main.c |   33 ++++++++++++++++++++++-----------
 1 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5e12462..c3d98dd 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -168,7 +168,7 @@ static int arp_ip_count;
 static int bond_mode	= BOND_MODE_ROUNDROBIN;
 static int xmit_hashtype = BOND_XMIT_POLICY_LAYER2;
 static int lacp_fast;
-
+static int disable_netpoll = 1;
 
 const struct bond_parm_tbl bond_lacp_tbl[] = {
 {	"slow",		AD_LACP_SLOW},
@@ -1742,15 +1742,23 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	bond_set_carrier(bond);
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
-	if (slaves_support_netpoll(bond_dev)) {
-		bond_dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
-		if (bond_dev->npinfo)
-			slave_dev->npinfo = bond_dev->npinfo;
-	} else if (!(bond_dev->priv_flags & IFF_DISABLE_NETPOLL)) {
+	/*
+	 * 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;
-		pr_info("New slave device %s does not support netpoll\n",
-			slave_dev->name);
-		pr_info("Disabling netpoll support for %s\n", bond_dev->name);
+	} else {
+		if (slaves_support_netpoll(bond_dev)) {
+			bond_dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
+			if (bond_dev->npinfo)
+				slave_dev->npinfo = bond_dev->npinfo;
+		} else if (!(bond_dev->priv_flags & IFF_DISABLE_NETPOLL)) {
+			bond_dev->priv_flags |= IFF_DISABLE_NETPOLL;
+			pr_info("New slave device %s does not support netpoll\n",
+				slave_dev->name);
+			pr_info("Disabling netpoll support for %s\n", bond_dev->name);
+		}
 	}
 #endif
 	read_unlock(&bond->lock);
@@ -1950,8 +1958,11 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	read_lock_bh(&bond->lock);
-	if (slaves_support_netpoll(bond_dev))
-		bond_dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
+
+	 /* Make sure netpoll over stays disabled until fixed. */
+	if (!disable_netpoll)
+		if (slaves_support_netpoll(bond_dev))
+				bond_dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
 	read_unlock_bh(&bond->lock);
 	if (slave_dev->netdev_ops->ndo_netpoll_cleanup)
 		slave_dev->netdev_ops->ndo_netpoll_cleanup(slave_dev);
--
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