[GENETLINK] ctrl: Avoid empty CTRL_ATTR_OPS attribute when dumping

Based on Jamal's patch but compiled and even tested. :-)

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 8903ef9..cc874f0 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -394,10 +394,7 @@ static struct genl_family genl_ctrl = {
 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
                          u32 flags, struct sk_buff *skb, u8 cmd)
 {
-       struct nlattr *nla_ops;
-       struct genl_ops *ops;
        void *hdr;
-       int idx = 1;
 
        hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
        if (hdr == NULL)
@@ -409,33 +406,39 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
        NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
        NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 
-       nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
-       if (nla_ops == NULL)
-               goto nla_put_failure;
-
-       list_for_each_entry(ops, &family->ops_list, ops_list) {
-               struct nlattr *nest;
+       if (!list_empty(&family->ops_list)) {
+               struct nlattr *nla_ops;
+               struct genl_ops *ops;
+               int idx = 1;
 
-               nest = nla_nest_start(skb, idx++);
-               if (nest == NULL)
+               nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
+               if (nla_ops == NULL)
                        goto nla_put_failure;
 
-               NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
-               NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
+               list_for_each_entry(ops, &family->ops_list, ops_list) {
+                       struct nlattr *nest;
 
-               if (ops->policy)
-                       NLA_PUT_FLAG(skb, CTRL_ATTR_OP_POLICY);
+                       nest = nla_nest_start(skb, idx++);
+                       if (nest == NULL)
+                               goto nla_put_failure;
 
-               if (ops->doit)
-                       NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DOIT);
+                       NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
+                       NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 
-               if (ops->dumpit)
-                       NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DUMPIT);
+                       if (ops->policy)
+                               NLA_PUT_FLAG(skb, CTRL_ATTR_OP_POLICY);
 
-               nla_nest_end(skb, nest);
-       }
+                       if (ops->doit)
+                               NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DOIT);
+
+                       if (ops->dumpit)
+                               NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DUMPIT);
 
-       nla_nest_end(skb, nla_ops);
+                       nla_nest_end(skb, nest);
+               }
+
+               nla_nest_end(skb, nla_ops);
+       }
 
        return genlmsg_end(skb, hdr);