bonding: use __dev_get_by_name instead of dev_get_by_name to find interface

The following call chain indicates that bond_do_ioctl() is protected
under rtnl_lock. If we use __dev_get_by_name() instead of
dev_get_by_name() to find interface handler in it, this would
help us avoid to change reference counter of interface once.

dev_ioctl()
  rtnl_lock()
  dev_ifsioc()
    bond_do_ioctl()
  rtnl_unlock()

Additionally we also change the coding style in bond_do_ioctl(),
letting it more readable for us.

Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Veaceslav Falico <vfalico@redhat.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 7069b84..f2fe6cb 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3213,37 +3213,34 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;
 
-       slave_dev = dev_get_by_name(net, ifr->ifr_slave);
+       slave_dev = __dev_get_by_name(net, ifr->ifr_slave);
 
        pr_debug("slave_dev=%p:\n", slave_dev);
 
        if (!slave_dev)
-               res = -ENODEV;
-       else {
-               pr_debug("slave_dev->name=%s:\n", slave_dev->name);
-               switch (cmd) {
-               case BOND_ENSLAVE_OLD:
-               case SIOCBONDENSLAVE:
-                       res = bond_enslave(bond_dev, slave_dev);
-                       break;
-               case BOND_RELEASE_OLD:
-               case SIOCBONDRELEASE:
-                       res = bond_release(bond_dev, slave_dev);
-                       break;
-               case BOND_SETHWADDR_OLD:
-               case SIOCBONDSETHWADDR:
-                       bond_set_dev_addr(bond_dev, slave_dev);
-                       res = 0;
-                       break;
-               case BOND_CHANGE_ACTIVE_OLD:
-               case SIOCBONDCHANGEACTIVE:
-                       res = bond_option_active_slave_set(bond, slave_dev);
-                       break;
-               default:
-                       res = -EOPNOTSUPP;
-               }
+               return -ENODEV;
 
-               dev_put(slave_dev);
+       pr_debug("slave_dev->name=%s:\n", slave_dev->name);
+       switch (cmd) {
+       case BOND_ENSLAVE_OLD:
+       case SIOCBONDENSLAVE:
+               res = bond_enslave(bond_dev, slave_dev);
+               break;
+       case BOND_RELEASE_OLD:
+       case SIOCBONDRELEASE:
+               res = bond_release(bond_dev, slave_dev);
+               break;
+       case BOND_SETHWADDR_OLD:
+       case SIOCBONDSETHWADDR:
+               bond_set_dev_addr(bond_dev, slave_dev);
+               res = 0;
+               break;
+       case BOND_CHANGE_ACTIVE_OLD:
+       case SIOCBONDCHANGEACTIVE:
+               res = bond_option_active_slave_set(bond, slave_dev);
+               break;
+       default:
+               res = -EOPNOTSUPP;
        }
 
        return res;