net: sched: move frag check and tc_skb_cb update out of handle_fragments

This patch has no functional changes and just moves frag check and
tc_skb_cb update out of handle_fragments, to make it easier to move
the duplicate code from handle_fragments() into nf_conntrack_ovs later.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched/act_ct.c

@@ -778,29 +778,10 @@ static int tcf_ct_ipv6_is_fragment(struct sk_buff *skb, bool *frag)
 	return 0;
 }
 
-static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
-				   u8 family, u16 zone, bool *defrag)
+static int handle_fragments(struct net *net, struct sk_buff *skb,
+			    u16 zone, u8 family, u16 *mru)
 {
-	enum ip_conntrack_info ctinfo;
-	struct nf_conn *ct;
-	int err = 0;
-	bool frag;
-	u16 mru;
-
-	/* Previously seen (loopback)? Ignore. */
-	ct = nf_ct_get(skb, &ctinfo);
-	if ((ct && !nf_ct_is_template(ct)) || ctinfo == IP_CT_UNTRACKED)
-		return 0;
-
-	if (family == NFPROTO_IPV4)
-		err = tcf_ct_ipv4_is_fragment(skb, &frag);
-	else
-		err = tcf_ct_ipv6_is_fragment(skb, &frag);
-	if (err || !frag)
-		return err;
-
-	skb_get(skb);
-	mru = tc_skb_cb(skb)->mru;
+	int err;
 
 	if (family == NFPROTO_IPV4) {
 		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
@@ -812,10 +793,8 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
 		if (err && err != -EINPROGRESS)
 			return err;
 
-		if (!err) {
-			*defrag = true;
-			mru = IPCB(skb)->frag_max_size;
-		}
+		if (!err)
+			*mru = IPCB(skb)->frag_max_size;
 	} else { /* NFPROTO_IPV6 */
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
 		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
@@ -825,18 +804,14 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
 		if (err && err != -EINPROGRESS)
 			goto out_free;
 
-		if (!err) {
-			*defrag = true;
-			mru = IP6CB(skb)->frag_max_size;
-		}
+		if (!err)
+			*mru = IP6CB(skb)->frag_max_size;
 #else
 		err = -EOPNOTSUPP;
 		goto out_free;
 #endif
 	}
 
-	if (err != -EINPROGRESS)
-		tc_skb_cb(skb)->mru = mru;
 	skb_clear_hash(skb);
 	skb->ignore_df = 1;
 	return err;
@@ -846,6 +821,38 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
 	return err;
 }
 
+static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
+				   u8 family, u16 zone, bool *defrag)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+	int err = 0;
+	bool frag;
+	u16 mru;
+
+	/* Previously seen (loopback)? Ignore. */
+	ct = nf_ct_get(skb, &ctinfo);
+	if ((ct && !nf_ct_is_template(ct)) || ctinfo == IP_CT_UNTRACKED)
+		return 0;
+
+	if (family == NFPROTO_IPV4)
+		err = tcf_ct_ipv4_is_fragment(skb, &frag);
+	else
+		err = tcf_ct_ipv6_is_fragment(skb, &frag);
+	if (err || !frag)
+		return err;
+
+	skb_get(skb);
+	err = handle_fragments(net, skb, zone, family, &mru);
+	if (err)
+		return err;
+
+	*defrag = true;
+	tc_skb_cb(skb)->mru = mru;
+
+	return 0;
+}
+
 static void tcf_ct_params_free(struct tcf_ct_params *params)
 {
 	if (params->helper) {