Subject: [PATCH net-next 21/21] net/ipv6: Remove unused code and variables for rt6_info

From: David Ahern <[email-masked]>
Date: Mon, 16 Apr 2018 08:22:55 -0700

Drop unneeded elements from rt6_info struct and rearrange layout to
something more relevant for the data path.

Signed-off-by: David Ahern <[email-masked]>
---
 include/net/ip6_fib.h   | 60 +++----------------------------------------------
 net/ipv6/ip6_fib.c      | 22 ------------------
 net/ipv6/route.c        | 27 ++--------------------
 net/ipv6/xfrm6_policy.c |  2 --
 4 files changed, 5 insertions(+), 106 deletions(-)

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index d41b7bd69fb3..a36116b92100 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -175,58 +175,20 @@ struct fib6_info {
 
 struct rt6_info {
 	struct dst_entry		dst;
-	struct rt6_info __rcu		*rt6_next;
 	struct fib6_info		*from;
 
-	/*
-	 * Tail elements of dst_entry (__refcnt etc.)
-	 * and these elements (rarely used in hot path) are in
-	 * the same cache line.
-	 */
-	struct fib6_table		*rt6i_table;
-	struct fib6_node __rcu		*rt6i_node;
-
+	struct rt6key			rt6i_dst;
+	struct rt6key			rt6i_src;
 	struct in6_addr			rt6i_gateway;
-
-	/* Multipath routes:
-	 * siblings is a list of rt6_info that have the the same metric/weight,
-	 * destination, but not the same gateway. nsiblings is just a cache
-	 * to speed up lookup.
-	 */
-	struct list_head		rt6i_siblings;
-	unsigned int			rt6i_nsiblings;
-
-	atomic_t			rt6i_ref;
-
-	/* These are in a separate cache line. */
-	struct rt6key			rt6i_dst ____cacheline_aligned_in_smp;
+	struct inet6_dev		*rt6i_idev;
 	u32				rt6i_flags;
-	struct rt6key			rt6i_src;
 	struct rt6key			rt6i_prefsrc;
 
 	struct list_head		rt6i_uncached;
 	struct uncached_list		*rt6i_uncached_list;
 
-	struct inet6_dev		*rt6i_idev;
-	struct rt6_info * __percpu	*rt6i_pcpu;
-	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
-
-	u32				rt6i_metric;
 	/* more non-fragment space at head required */
 	unsigned short			rt6i_nfheader_len;
-	u8				rt6i_protocol;
-	u8				fib6_type;
-	u8				exception_bucket_flushed:1,
-					should_flush:1,
-					dst_nocount:1,
-					dst_nopolicy:1,
-					dst_host:1,
-					unused:3;
-
-	unsigned long			expires;
-	struct dst_metrics		*fib6_metrics;
-#define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]
-	struct fib6_nh			fib6_nh;
 };
 
 #define for_each_fib6_node_rt_rcu(fn)					\
@@ -328,8 +290,6 @@ static inline void ip6_rt_put(struct rt6_info *rt)
 	dst_release(&rt->dst);
 }
 
-void rt6_free_pcpu(struct rt6_info *non_pcpu_rt);
-
 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
 void fib6_info_destroy(struct fib6_info *f6i);
 
@@ -344,20 +304,6 @@ static inline void fib6_info_release(struct fib6_info *f6i)
 		fib6_info_destroy(f6i);
 }
 
-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,
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 77cf43b2d858..2ab49b7cac22 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -240,28 +240,6 @@ static void node_free(struct net *net, struct fib6_node *fn)
 	net->ipv6.rt6_stats->fib_nodes--;
 }
 
-void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
-{
-	int cpu;
-
-	if (!non_pcpu_rt->rt6i_pcpu)
-		return;
-
-	for_each_possible_cpu(cpu) {
-		struct rt6_info **ppcpu_rt;
-		struct rt6_info *pcpu_rt;
-
-		ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
-		pcpu_rt = *ppcpu_rt;
-		if (pcpu_rt) {
-			dst_dev_put(&pcpu_rt->dst);
-			dst_release(&pcpu_rt->dst);
-			*ppcpu_rt = NULL;
-		}
-	}
-}
-EXPORT_SYMBOL_GPL(rt6_free_pcpu);
-
 static void fib6_free_table(struct fib6_table *table)
 {
 	inetpeer_invalidate_tree(&table->tb6_peers);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b53b28a59151..fb4e996ca15b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -302,10 +302,6 @@ static const struct rt6_info ip6_null_entry_template = {
 		.output		= ip6_pkt_discard_out,
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
-	.rt6i_protocol  = RTPROT_KERNEL,
-	.rt6i_metric	= ~(u32) 0,
-	.rt6i_ref	= ATOMIC_INIT(1),
-	.fib6_type	= RTN_UNREACHABLE,
 };
 
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
@@ -320,10 +316,6 @@ static const struct rt6_info ip6_prohibit_entry_template = {
 		.output		= ip6_pkt_prohibit_out,
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
-	.rt6i_protocol  = RTPROT_KERNEL,
-	.rt6i_metric	= ~(u32) 0,
-	.rt6i_ref	= ATOMIC_INIT(1),
-	.fib6_type	= RTN_PROHIBIT,
 };
 
 static const struct rt6_info ip6_blk_hole_entry_template = {
@@ -336,10 +328,6 @@ static const struct rt6_info ip6_blk_hole_entry_template = {
 		.output		= dst_discard_out,
 	},
 	.rt6i_flags	= (RTF_REJECT | RTF_NONEXTHOP),
-	.rt6i_protocol  = RTPROT_KERNEL,
-	.rt6i_metric	= ~(u32) 0,
-	.rt6i_ref	= ATOMIC_INIT(1),
-	.fib6_type	= RTN_BLACKHOLE,
 };
 
 #endif
@@ -349,7 +337,6 @@ static void rt6_info_init(struct rt6_info *rt)
 	struct dst_entry *dst = &rt->dst;
 
 	memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst));
-	INIT_LIST_HEAD(&rt->rt6i_siblings);
 	INIT_LIST_HEAD(&rt->rt6i_uncached);
 }
 
@@ -999,12 +986,10 @@ static void ip6_rt_copy_init(struct rt6_info *rt, struct fib6_info *ort)
 	rt->rt6i_gateway = ort->fib6_nh.nh_gw;
 	rt->rt6i_flags = ort->rt6i_flags;
 	rt6_set_from(rt, ort);
-	rt->rt6i_metric = ort->rt6i_metric;
 #ifdef CONFIG_IPV6_SUBTREES
 	rt->rt6i_src = ort->rt6i_src;
 #endif
 	rt->rt6i_prefsrc = ort->rt6i_prefsrc;
-	rt->rt6i_table = ort->rt6i_table;
 	rt->dst.lwtstate = lwtstate_get(ort->fib6_nh.nh_lwtstate);
 }
 
@@ -1192,7 +1177,6 @@ static struct rt6_info *ip6_rt_cache_alloc(struct fib6_info *ort,
 
 	ip6_rt_copy_init(rt, ort);
 	rt->rt6i_flags |= RTF_CACHE;
-	rt->rt6i_metric = 0;
 	rt->dst.flags |= DST_HOST;
 	rt->rt6i_dst.addr = *daddr;
 	rt->rt6i_dst.plen = 128;
@@ -1225,7 +1209,6 @@ static struct rt6_info *ip6_rt_pcpu_alloc(struct fib6_info *rt)
 	if (!pcpu_rt)
 		return NULL;
 	ip6_rt_copy_init(pcpu_rt, rt);
-	pcpu_rt->rt6i_protocol = rt->rt6i_protocol;
 	pcpu_rt->rt6i_flags |= RTF_PCPU;
 	return pcpu_rt;
 }
@@ -1279,9 +1262,8 @@ static void rt6_remove_exception(struct rt6_exception_bucket *bucket,
 		return;
 
 	net = dev_net(rt6_ex->rt6i->dst.dev);
-	rt6_ex->rt6i->rt6i_node = NULL;
 	hlist_del_rcu(&rt6_ex->hlist);
-	ip6_rt_put(rt6_ex->rt6i);
+	dst_release(&rt6_ex->rt6i->dst);
 	kfree_rcu(rt6_ex, rcu);
 	WARN_ON_ONCE(!bucket->depth);
 	bucket->depth--;
@@ -1463,8 +1445,6 @@ static int rt6_insert_exception(struct rt6_info *nrt,
 	}
 	rt6_ex->rt6i = nrt;
 	rt6_ex->stamp = jiffies;
-	atomic_inc(&nrt->rt6i_ref);
-	nrt->rt6i_node = ort->rt6i_node;
 	hlist_add_head_rcu(&rt6_ex->hlist, &bucket->chain);
 	bucket->depth++;
 	net->ipv6.rt6_stats->fib_rt_cache++;
@@ -2122,7 +2102,6 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
 		rt->rt6i_idev = in6_dev_get(loopback_dev);
 		rt->rt6i_gateway = ort->rt6i_gateway;
 		rt->rt6i_flags = ort->rt6i_flags & ~RTF_PCPU;
-		rt->rt6i_metric = 0;
 
 		memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
 #ifdef CONFIG_IPV6_SUBTREES
@@ -2247,8 +2226,7 @@ static void rt6_do_update_pmtu(struct rt6_info *rt, u32 mtu)
 static bool rt6_cache_allowed_for_pmtu(const struct rt6_info *rt)
 {
 	return !(rt->rt6i_flags & RTF_CACHE) &&
-		(rt->rt6i_flags & RTF_PCPU ||
-		 rcu_access_pointer(rt->rt6i_node));
+		(rt->rt6i_flags & RTF_PCPU || rt->from);
 }
 
 static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
@@ -3313,7 +3291,6 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 	if (on_link)
 		nrt->rt6i_flags &= ~RTF_GATEWAY;
 
-	nrt->rt6i_protocol = RTPROT_REDIRECT;
 	nrt->rt6i_gateway = *(struct in6_addr *)neigh->primary_key;
 
 	/* No need to remove rt from the exception table if rt is
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 416fe67271a9..2cff209d0fc1 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -107,8 +107,6 @@ static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	 * it was magically lost, so this code needs audit */
 	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 						   RTF_LOCAL);
-	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
-	xdst->u.rt6.rt6i_node = rt->rt6i_node;
 	xdst->route_cookie = rt6_get_cookie(rt);
 	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
-- 
2.11.0