Commit 3dec89b1 authored by Kui-Feng Lee's avatar Kui-Feng Lee Committed by David S. Miller
Browse files

net/ipv6: Remove expired routes with a separated list of routes. 



FIB6 GC walks trees of fib6_tables to remove expired routes. Walking a tree
can be expensive if the number of routes in a table is big, even if most of
them are permanent. Checking routes in a separated list of routes having
expiration will avoid this potential issue.

Signed-off-by: default avatarKui-Feng Lee <thinker.li@gmail.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d1470851

include/net/ip6_fib.h

+51 −13
Original line number Diff line number Diff line
@@ -179,6 +179,9 @@ struct fib6_info { 


	refcount_t			fib6_ref;

	unsigned long			expires;



	struct hlist_node		gc_link;



	struct dst_metrics		*fib6_metrics;

#define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]
@@ -247,19 +250,6 @@ static inline bool fib6_requires_src(const struct fib6_info *rt) 
	return rt->fib6_src.plen > 0;

}



static inline void fib6_clean_expires(struct fib6_info *f6i)

{

	f6i->fib6_flags &= ~RTF_EXPIRES;

	f6i->expires = 0;

}



static inline void fib6_set_expires(struct fib6_info *f6i,

				    unsigned long expires)

{

	f6i->expires = expires;

	f6i->fib6_flags |= RTF_EXPIRES;

}



static inline bool fib6_check_expired(const struct fib6_info *f6i)

{

	if (f6i->fib6_flags & RTF_EXPIRES)
@@ -267,6 +257,11 @@ static inline bool fib6_check_expired(const struct fib6_info *f6i) 
	return false;

}



static inline bool fib6_has_expires(const struct fib6_info *f6i)

{

	return f6i->fib6_flags & RTF_EXPIRES;

}



/* Function to safely get fn->fn_sernum for passed in rt

 * and store result in passed in cookie.

 * Return true if we can get cookie safely
@@ -388,6 +383,7 @@ struct fib6_table { 
	struct inet_peer_base	tb6_peers;

	unsigned int		flags;

	unsigned int		fib_seq;

	struct hlist_head       tb6_gc_hlist;	/* GC candidates */

#define RT6_TABLE_HAS_DFLT_ROUTER	BIT(0)

};
@@ -504,6 +500,48 @@ void fib6_gc_cleanup(void); 


int fib6_init(void);



/* fib6_info must be locked by the caller, and fib6_info->fib6_table can be

 * NULL.

 */

static inline void fib6_set_expires_locked(struct fib6_info *f6i,

					   unsigned long expires)

{

	struct fib6_table *tb6;



	tb6 = f6i->fib6_table;

	f6i->expires = expires;

	if (tb6 && !fib6_has_expires(f6i))

		hlist_add_head(&f6i->gc_link, &tb6->tb6_gc_hlist);

	f6i->fib6_flags |= RTF_EXPIRES;

}



/* fib6_info must be locked by the caller, and fib6_info->fib6_table can be

 * NULL.  If fib6_table is NULL, the fib6_info will no be inserted into the

 * list of GC candidates until it is inserted into a table.

 */

static inline void fib6_set_expires(struct fib6_info *f6i,

				    unsigned long expires)

{

	spin_lock_bh(&f6i->fib6_table->tb6_lock);

	fib6_set_expires_locked(f6i, expires);

	spin_unlock_bh(&f6i->fib6_table->tb6_lock);

}



static inline void fib6_clean_expires_locked(struct fib6_info *f6i)

{

	if (fib6_has_expires(f6i))

		hlist_del_init(&f6i->gc_link);

	f6i->fib6_flags &= ~RTF_EXPIRES;

	f6i->expires = 0;

}



static inline void fib6_clean_expires(struct fib6_info *f6i)

{

	spin_lock_bh(&f6i->fib6_table->tb6_lock);

	fib6_clean_expires_locked(f6i);

	spin_unlock_bh(&f6i->fib6_table->tb6_lock);

}



struct ipv6_route_iter {

	struct seq_net_private p;

	struct fib6_walker w;

net/ipv6/ip6_fib.c

+49 −6
Original line number Diff line number Diff line
@@ -160,6 +160,8 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh) 
	INIT_LIST_HEAD(&f6i->fib6_siblings);

	refcount_set(&f6i->fib6_ref, 1);



	INIT_HLIST_NODE(&f6i->gc_link);



	return f6i;

}
@@ -246,6 +248,7 @@ static struct fib6_table *fib6_alloc_table(struct net *net, u32 id) 
				   net->ipv6.fib6_null_entry);

		table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;

		inet_peer_base_init(&table->tb6_peers);

		INIT_HLIST_HEAD(&table->tb6_gc_hlist);

	}



	return table;
@@ -1057,6 +1060,8 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, 
				    lockdep_is_held(&table->tb6_lock));

		}

	}



	fib6_clean_expires_locked(rt);

}



/*
@@ -1118,9 +1123,10 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
				if (!(iter->fib6_flags & RTF_EXPIRES))

					return -EEXIST;

				if (!(rt->fib6_flags & RTF_EXPIRES))

					fib6_clean_expires(iter);

					fib6_clean_expires_locked(iter);

				else

					fib6_set_expires(iter, rt->expires);

					fib6_set_expires_locked(iter,

								rt->expires);



				if (rt->fib6_pmtu)

					fib6_metric_set(iter, RTAX_MTU,
@@ -1479,6 +1485,10 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt, 
		if (rt->nh)

			list_add(&rt->nh_list, &rt->nh->f6i_list);

		__fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));



		if (fib6_has_expires(rt))

			hlist_add_head(&rt->gc_link, &table->tb6_gc_hlist);



		fib6_start_gc(info->nl_net, rt);

	}
@@ -2285,9 +2295,8 @@ static void fib6_flush_trees(struct net *net) 
 *	Garbage collection

 */



static int fib6_age(struct fib6_info *rt, void *arg)

static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)

{

	struct fib6_gc_args *gc_args = arg;

	unsigned long now = jiffies;



	/*
@@ -2295,7 +2304,7 @@ static int fib6_age(struct fib6_info *rt, void *arg) 
	 *	Routes are expired even if they are in use.

	 */



	if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {

	if (fib6_has_expires(rt) && rt->expires) {

		if (time_after(now, rt->expires)) {

			RT6_TRACE("expiring %p\n", rt);

			return -1;
@@ -2312,6 +2321,40 @@ static int fib6_age(struct fib6_info *rt, void *arg) 
	return 0;

}



static void fib6_gc_table(struct net *net,

			  struct fib6_table *tb6,

			  struct fib6_gc_args *gc_args)

{

	struct fib6_info *rt;

	struct hlist_node *n;

	struct nl_info info = {

		.nl_net = net,

		.skip_notify = false,

	};



	hlist_for_each_entry_safe(rt, n, &tb6->tb6_gc_hlist, gc_link)

		if (fib6_age(rt, gc_args) == -1)

			fib6_del(rt, &info);

}



static void fib6_gc_all(struct net *net, struct fib6_gc_args *gc_args)

{

	struct fib6_table *table;

	struct hlist_head *head;

	unsigned int h;



	rcu_read_lock();

	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {

		head = &net->ipv6.fib_table_hash[h];

		hlist_for_each_entry_rcu(table, head, tb6_hlist) {

			spin_lock_bh(&table->tb6_lock);

			fib6_gc_table(net, table, gc_args);

			spin_unlock_bh(&table->tb6_lock);

		}

	}

	rcu_read_unlock();

}



void fib6_run_gc(unsigned long expires, struct net *net, bool force)

{

	struct fib6_gc_args gc_args;
@@ -2327,7 +2370,7 @@ void fib6_run_gc(unsigned long expires, struct net *net, bool force) 
			  net->ipv6.sysctl.ip6_rt_gc_interval;

	gc_args.more = 0;



	fib6_clean_all(net, fib6_age, &gc_args);

	fib6_gc_all(net, &gc_args);

	now = jiffies;

	net->ipv6.ip6_rt_last_gc = now;

net/ipv6/route.c

+3 −3
Original line number Diff line number Diff line
@@ -3761,10 +3761,10 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg, 
		rt->dst_nocount = true;



	if (cfg->fc_flags & RTF_EXPIRES)

		fib6_set_expires(rt, jiffies +

		fib6_set_expires_locked(rt, jiffies +

					clock_t_to_jiffies(cfg->fc_expires));

	else

		fib6_clean_expires(rt);

		fib6_clean_expires_locked(rt);



	if (cfg->fc_protocol == RTPROT_UNSPEC)

		cfg->fc_protocol = RTPROT_BOOT;