bonding: "primary_reselect" with "failure" is not working properly

When "primary_reselect" is set to "failure", primary interface should
not become active until current active slave is down. But if we set first
member of bond device as a "primary" interface and "primary_reselect"
is set to "failure" then whenever primary interface's link get back(up)
it become active slave even if current active slave is still up.

With this patch, "bond_find_best_slave" will not traverse members if
primary interface is not candidate for failover/reselection and current
active slave is still up.

Signed-off-by: Mazhar Rana <mazhar.rana@cyberoam.com>
Signed-off-by: Jay Vosburgh <j.vosburgh@gmail.com>
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 17 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 19eb990d398c..317a49480475 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -689,40 +689,57 @@ out:
 
 }
 
-static bool bond_should_change_active(struct bonding *bond)
+static struct slave *bond_choose_primary_or_current(struct bonding *bond)
 {
         struct slave *prim = rtnl_dereference(bond->primary_slave);
         struct slave *curr = rtnl_dereference(bond->curr_active_slave);
 
-        if (!prim || !curr || curr->link != BOND_LINK_UP)
-                return true;
+        if (!prim || prim->link != BOND_LINK_UP) {
+                if (!curr || curr->link != BOND_LINK_UP)
+                        return NULL;
+                return curr;
+        }
+
         if (bond->force_primary) {
                 bond->force_primary = false;
-                return true;
+                return prim;
+        }
+
+        if (!curr || curr->link != BOND_LINK_UP)
+                return prim;
+
+        /* At this point, prim and curr are both up */
+        switch (bond->params.primary_reselect) {
+        case BOND_PRI_RESELECT_ALWAYS:
+                return prim;
+        case BOND_PRI_RESELECT_BETTER:
+                if (prim->speed < curr->speed)
+                        return curr;
+                if (prim->speed == curr->speed && prim->duplex <= curr->duplex)
+                        return curr;
+                return prim;
+        case BOND_PRI_RESELECT_FAILURE:
+                return curr;
+        default:
+                netdev_err(bond->dev, "impossible primary_reselect %d\n",
+                           bond->params.primary_reselect);
+                return curr;
         }
-        if (bond->params.primary_reselect == BOND_PRI_RESELECT_BETTER &&
-            (prim->speed < curr->speed ||
-             (prim->speed == curr->speed && prim->duplex <= curr->duplex)))
-                return false;
-        if (bond->params.primary_reselect == BOND_PRI_RESELECT_FAILURE)
-                return false;
-        return true;
 }
 
 /**
- * find_best_interface - select the best available slave to be the active one
+ * bond_find_best_slave - select the best available slave to be the active one
  * @bond: our bonding struct
  */
 static struct slave *bond_find_best_slave(struct bonding *bond)
 {
-        struct slave *slave, *bestslave = NULL, *primary;
+        struct slave *slave, *bestslave = NULL;
         struct list_head *iter;
         int mintime = bond->params.updelay;
 
-        primary = rtnl_dereference(bond->primary_slave);
-        if (primary && primary->link == BOND_LINK_UP &&
-            bond_should_change_active(bond))
-                return primary;
+        slave = bond_choose_primary_or_current(bond);
+        if (slave)
+                return slave;
 
         bond_for_each_slave(bond, slave, iter) {
                 if (slave->link == BOND_LINK_UP)