bonding: prevent sysfs from allowing arp monitoring with alb/tlb

When using module options arp monitoring and balance-alb/balance-tlb
are mutually exclusive options.  Anytime balance-alb/balance-tlb are
enabled mii monitoring is forced to 100ms if not set.  When configuring
via sysfs no checking is currently done.

Handling these cases with sysfs has to be done a bit differently because
we do not have all configuration information available at once.  This
patch will not allow a mode change to balance-alb/balance-tlb if
arp_interval is already non-zero.  It will also not allow the user to
set a non-zero arp_interval value if the mode is already set to
balance-alb/balance-tlb.  They are still mutually exclusive on a
first-come, first serve basis.

Tested with initscripts on Fedora and manual setting via sysfs.

Signed-off-by: Andy Gospodarek <gospo@redhat.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 12 deletions

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 1a9976487099..c311aed9bd02 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -313,19 +313,26 @@ static ssize_t bonding_store_mode(struct device *d,
                        bond->dev->name, (int)strlen(buf) - 1, buf);
                 ret = -EINVAL;
                 goto out;
-        } else {
-                if (bond->params.mode == BOND_MODE_8023AD)
-                        bond_unset_master_3ad_flags(bond);
+        }
+        if ((new_value == BOND_MODE_ALB ||
+             new_value == BOND_MODE_TLB) &&
+            bond->params.arp_interval) {
+                pr_err("%s: %s mode is incompatible with arp monitoring.\n",
+                       bond->dev->name, bond_mode_tbl[new_value].modename);
+                ret = -EINVAL;
+                goto out;
+        }
+        if (bond->params.mode == BOND_MODE_8023AD)
+                bond_unset_master_3ad_flags(bond);
 
-                if (bond->params.mode == BOND_MODE_ALB)
-                        bond_unset_master_alb_flags(bond);
+        if (bond->params.mode == BOND_MODE_ALB)
+                bond_unset_master_alb_flags(bond);
 
-                bond->params.mode = new_value;
-                bond_set_mode_ops(bond, bond->params.mode);
-                pr_info("%s: setting mode to %s (%d).\n",
-                        bond->dev->name, bond_mode_tbl[new_value].modename,
-                       new_value);
-        }
+        bond->params.mode = new_value;
+        bond_set_mode_ops(bond, bond->params.mode);
+        pr_info("%s: setting mode to %s (%d).\n",
+                bond->dev->name, bond_mode_tbl[new_value].modename,
+                new_value);
 out:
         return ret;
 }
@@ -510,7 +517,13 @@ static ssize_t bonding_store_arp_interval(struct device *d,
                 ret = -EINVAL;
                 goto out;
         }
-
+        if (bond->params.mode == BOND_MODE_ALB ||
+            bond->params.mode == BOND_MODE_TLB) {
+                pr_info("%s: ARP monitoring cannot be used with ALB/TLB. Only MII monitoring is supported on %s.\n",
+                        bond->dev->name, bond->dev->name);
+                ret = -EINVAL;
+                goto out;
+        }
         pr_info("%s: Setting ARP monitoring interval to %d.\n",
                 bond->dev->name, new_value);
         bond->params.arp_interval = new_value;