genetlink: factor skb preparation out of ctrl_dumppolicy()

We'll need this later for the per-op policy index dump.

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 89646b9..5e33c79 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1154,6 +1154,24 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
                                              rt->maxattr);
 }
 
+static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
+                                 struct netlink_callback *cb)
+{
+       struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+       void *hdr;
+
+       hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+                         cb->nlh->nlmsg_seq, &genl_ctrl,
+                         NLM_F_MULTI, CTRL_CMD_GETPOLICY);
+       if (!hdr)
+               return NULL;
+
+       if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
+               return NULL;
+
+       return hdr;
+}
+
 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
 {
        struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
@@ -1162,15 +1180,10 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
                void *hdr;
                struct nlattr *nest;
 
-               hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
-                                 cb->nlh->nlmsg_seq, &genl_ctrl,
-                                 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
+               hdr = ctrl_dumppolicy_prep(skb, cb);
                if (!hdr)
                        goto nla_put_failure;
 
-               if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
-                       goto nla_put_failure;
-
                nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
                if (!nest)
                        goto nla_put_failure;