bonding: Don't allow mode change via sysfs with slaves present

When changing mode via bonding's sysfs, the slaves are not initialized
correctly. Forbid to change modes with slaves present to ensure that every
slave is initialized correctly via bond_enslave().

Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Acked-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 5a20804fdece8d1c281e310e49509973185a33ed..4ef7e2fd9fe6f5b577c13fc56a5b2ae45a54a0bd 100644 (file)
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -319,6 +319,13 @@ static ssize_t bonding_store_mode(struct device *d,
                goto out;
        }
 
+       if (bond->slave_cnt > 0) {
+               pr_err("unable to update mode of %s because it has slaves.\n",
+                       bond->dev->name);
+               ret = -EPERM;
+               goto out;
+       }
+
        new_value = bond_parse_parm(buf, bond_mode_tbl);
        if (new_value < 0)  {
                pr_err("%s: Ignoring invalid mode value %.*s.\n",