Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index f590446..f9e8fe3 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * net/ipv6/fib6_rules.c	IPv6 Routing Policy Rules
  *
  * Copyright (C)2003-2006 Helsinki University of Technology
  * Copyright (C)2003-2006 USAGI/WIDE Project
  *
- *	This program is free software; you can redistribute it and/or
- *	modify it under the terms of the GNU General Public License as
- *	published by the Free Software Foundation, version 2.
- *
  * Authors
  *	Thomas Graf		<tgraf@suug.ch>
  *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
@@ -61,16 +58,16 @@
 }
 
 /* called with rcu lock held; no reference taken on fib6_info */
-struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			      int flags)
+int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+		struct fib6_result *res, int flags)
 {
-	struct fib6_info *f6i;
 	int err;
 
 	if (net->ipv6.fib6_has_custom_rules) {
 		struct fib_lookup_arg arg = {
 			.lookup_ptr = fib6_table_lookup,
 			.lookup_data = &oif,
+			.result = res,
 			.flags = FIB_LOOKUP_NOREF,
 		};
 
@@ -78,19 +75,15 @@
 
 		err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
 				       flowi6_to_flowi(fl6), flags, &arg);
-		if (err)
-			return ERR_PTR(err);
-
-		f6i = arg.result ? : net->ipv6.fib6_null_entry;
 	} else {
-		f6i = fib6_table_lookup(net, net->ipv6.fib6_local_tbl,
-					oif, fl6, flags);
-		if (!f6i || f6i == net->ipv6.fib6_null_entry)
-			f6i = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
-						oif, fl6, flags);
+		err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
+					fl6, res, flags);
+		if (err || res->f6i == net->ipv6.fib6_null_entry)
+			err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
+						oif, fl6, res, flags);
 	}
 
-	return f6i;
+	return err;
 }
 
 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
@@ -98,9 +91,11 @@
 				   int flags, pol_lookup_t lookup)
 {
 	if (net->ipv6.fib6_has_custom_rules) {
+		struct fib6_result res = {};
 		struct fib_lookup_arg arg = {
 			.lookup_ptr = lookup,
 			.lookup_data = skb,
+			.result = &res,
 			.flags = FIB_LOOKUP_NOREF,
 		};
 
@@ -110,22 +105,23 @@
 		fib_rules_lookup(net->ipv6.fib6_rules_ops,
 				 flowi6_to_flowi(fl6), flags, &arg);
 
-		if (arg.result)
-			return arg.result;
+		if (res.rt6)
+			return &res.rt6->dst;
 	} else {
 		struct rt6_info *rt;
 
 		rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
 		if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
 			return &rt->dst;
-		ip6_rt_put(rt);
+		ip6_rt_put_flags(rt, flags);
 		rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 		if (rt->dst.error != -EAGAIN)
 			return &rt->dst;
-		ip6_rt_put(rt);
+		ip6_rt_put_flags(rt, flags);
 	}
 
-	dst_hold(&net->ipv6.ip6_null_entry->dst);
+	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
+		dst_hold(&net->ipv6.ip6_null_entry->dst);
 	return &net->ipv6.ip6_null_entry->dst;
 }
 
@@ -157,11 +153,11 @@
 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
 				int flags, struct fib_lookup_arg *arg)
 {
+	struct fib6_result *res = arg->result;
 	struct flowi6 *flp6 = &flp->u.ip6;
 	struct net *net = rule->fr_net;
 	struct fib6_table *table;
-	struct fib6_info *f6i;
-	int err = -EAGAIN, *oif;
+	int err, *oif;
 	u32 tb_id;
 
 	switch (rule->action) {
@@ -182,14 +178,12 @@
 		return -EAGAIN;
 
 	oif = (int *)arg->lookup_data;
-	f6i = fib6_table_lookup(net, table, *oif, flp6, flags);
-	if (f6i != net->ipv6.fib6_null_entry) {
+	err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
+	if (!err && res->f6i != net->ipv6.fib6_null_entry)
 		err = fib6_rule_saddr(net, rule, flags, flp6,
-				      fib6_info_nh_dev(f6i));
-
-		if (likely(!err))
-			arg->result = f6i;
-	}
+				      res->nh->fib_nh_dev);
+	else
+		err = -EAGAIN;
 
 	return err;
 }
@@ -197,6 +191,7 @@
 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
 			      int flags, struct fib_lookup_arg *arg)
 {
+	struct fib6_result *res = arg->result;
 	struct flowi6 *flp6 = &flp->u.ip6;
 	struct rt6_info *rt = NULL;
 	struct fib6_table *table;
@@ -243,15 +238,16 @@
 			goto out;
 	}
 again:
-	ip6_rt_put(rt);
+	ip6_rt_put_flags(rt, flags);
 	err = -EAGAIN;
 	rt = NULL;
 	goto out;
 
 discard_pkt:
-	dst_hold(&rt->dst);
+	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
+		dst_hold(&rt->dst);
 out:
-	arg->result = rt;
+	res->rt6 = rt;
 	return err;
 }
 
@@ -266,9 +262,13 @@
 
 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
 {
-	struct rt6_info *rt = (struct rt6_info *) arg->result;
+	struct fib6_result *res = arg->result;
+	struct rt6_info *rt = res->rt6;
 	struct net_device *dev = NULL;
 
+	if (!rt)
+		return false;
+
 	if (rt->rt6i_idev)
 		dev = rt->rt6i_idev->dev;
 
@@ -287,7 +287,8 @@
 	return false;
 
 suppress_route:
-	ip6_rt_put(rt);
+	if (!(arg->flags & FIB_LOOKUP_NOREF))
+		ip6_rt_put(rt);
 	return true;
 }