From: Ido Schimmel <idosch@mellanox.com>
Date: Thu, 3 Aug 2017 13:28:25 +0200
Subject: ipv6: fib: Add helpers to hold / drop a reference on rt6_info
Patch-mainline: v4.14-rc1
Git-commit: a460aa83963b185a32a6377eb486b6e613ac8e38
References: bsc#1112374

Similar to commit 1c677b3d2828 ("ipv4: fib: Add fib_info_hold() helper")
and commit b423cb10807b ("ipv4: fib: Export free_fib_info()") add an
helper to hold a reference on rt6_info and export rt6_release() to drop
it and potentially release the route.

This is needed so that drivers capable of FIB offload could hold a
reference on the route before queueing it for offload and drop it after
the route has been programmed to the device's tables.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/ip6_fib.h |   16 ++++++++++++++++
 net/ipv6/ip6_fib.c    |   12 ++----------
 2 files changed, 18 insertions(+), 10 deletions(-)

--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -212,6 +212,22 @@ static inline void ip6_rt_put(struct rt6
 	dst_release(&rt->dst);
 }
 
+void rt6_free_pcpu(struct rt6_info *non_pcpu_rt);
+
+static inline void rt6_hold(struct rt6_info *rt)
+{
+	atomic_inc(&rt->rt6i_ref);
+}
+
+static inline void rt6_release(struct rt6_info *rt)
+{
+	if (atomic_dec_and_test(&rt->rt6i_ref)) {
+		rt6_free_pcpu(rt);
+		dst_dev_put(&rt->dst);
+		dst_release(&rt->dst);
+	}
+}
+
 enum fib6_walk_state {
 #ifdef CONFIG_IPV6_SUBTREES
 	FWS_S,
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -166,7 +166,7 @@ static void node_free(struct fib6_node *
 	call_rcu(&fn->rcu, node_free_rcu);
 }
 
-static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
+void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
 {
 	int cpu;
 
@@ -189,15 +189,7 @@ static void rt6_free_pcpu(struct rt6_inf
 	free_percpu(non_pcpu_rt->rt6i_pcpu);
 	non_pcpu_rt->rt6i_pcpu = NULL;
 }
-
-static void rt6_release(struct rt6_info *rt)
-{
-	if (atomic_dec_and_test(&rt->rt6i_ref)) {
-		rt6_free_pcpu(rt);
-		dst_dev_put(&rt->dst);
-		dst_release(&rt->dst);
-	}
-}
+EXPORT_SYMBOL_GPL(rt6_free_pcpu);
 
 static void fib6_free_table(struct fib6_table *table)
 {