Commit 345e9b54 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

fib_trie: Push rcu_read_lock/unlock to callers 



This change is to start cleaning up some of the rcu_read_lock/unlock
handling.  I realized while reviewing the code there are several spots that
I don't believe are being handled correctly or are masking warnings by
locally calling rcu_read_lock/unlock instead of calling them at the correct
level.

A common example is a call to fib_get_table followed by fib_table_lookup.
The rcu_read_lock/unlock ought to wrap both but there are several spots where
they were not wrapped.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 98293e8d

include/net/ip_fib.h

+29 −21
Original line number Diff line number Diff line
@@ -222,16 +222,19 @@ static inline struct fib_table *fib_new_table(struct net *net, u32 id) 
static inline int fib_lookup(struct net *net, const struct flowi4 *flp,

			     struct fib_result *res)

{

	struct fib_table *table;

	int err = -ENETUNREACH;



	table = fib_get_table(net, RT_TABLE_LOCAL);

	if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))

		return 0;

	rcu_read_lock();



	table = fib_get_table(net, RT_TABLE_MAIN);

	if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))

		return 0;

	return -ENETUNREACH;

	if (!fib_table_lookup(fib_get_table(net, RT_TABLE_LOCAL), flp, res,

			      FIB_LOOKUP_NOREF) ||

	    !fib_table_lookup(fib_get_table(net, RT_TABLE_MAIN), flp, res,

			      FIB_LOOKUP_NOREF))

		err = 0;



	rcu_read_unlock();



	return err;

}



#else /* CONFIG_IP_MULTIPLE_TABLES */
@@ -247,20 +250,25 @@ static inline int fib_lookup(struct net *net, struct flowi4 *flp, 
			     struct fib_result *res)

{

	if (!net->ipv4.fib_has_custom_rules) {

		int err = -ENETUNREACH;



		rcu_read_lock();



		res->tclassid = 0;

		if (net->ipv4.fib_local &&

		if ((net->ipv4.fib_local &&

		     !fib_table_lookup(net->ipv4.fib_local, flp, res,

				      FIB_LOOKUP_NOREF))

			return 0;

		if (net->ipv4.fib_main &&

				       FIB_LOOKUP_NOREF)) ||

		    (net->ipv4.fib_main &&

		     !fib_table_lookup(net->ipv4.fib_main, flp, res,

				      FIB_LOOKUP_NOREF))

			return 0;

		if (net->ipv4.fib_default &&

				       FIB_LOOKUP_NOREF)) ||

		    (net->ipv4.fib_default &&

		     !fib_table_lookup(net->ipv4.fib_default, flp, res,

				      FIB_LOOKUP_NOREF))

			return 0;

		return -ENETUNREACH;

				       FIB_LOOKUP_NOREF)))

			err = 0;



		rcu_read_unlock();



		return err;

	}

	return __fib_lookup(net, flp, res);

}

net/ipv4/fib_frontend.c

+15 −12
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ struct fib_table *fib_new_table(struct net *net, u32 id) 
	return tb;

}



/* caller must hold either rtnl or rcu read lock */

struct fib_table *fib_get_table(struct net *net, u32 id)

{

	struct fib_table *tb;
@@ -119,15 +120,11 @@ struct fib_table *fib_get_table(struct net *net, u32 id) 
		id = RT_TABLE_MAIN;

	h = id & (FIB_TABLE_HASHSZ - 1);



	rcu_read_lock();

	head = &net->ipv4.fib_table_hash[h];

	hlist_for_each_entry_rcu(tb, head, tb_hlist) {

		if (tb->tb_id == id) {

			rcu_read_unlock();

		if (tb->tb_id == id)

			return tb;

	}

	}

	rcu_read_unlock();

	return NULL;

}

#endif /* CONFIG_IP_MULTIPLE_TABLES */
@@ -167,16 +164,18 @@ static inline unsigned int __inet_dev_addr_type(struct net *net, 
	if (ipv4_is_multicast(addr))

		return RTN_MULTICAST;



	rcu_read_lock();



	local_table = fib_get_table(net, RT_TABLE_LOCAL);

	if (local_table) {

		ret = RTN_UNICAST;

		rcu_read_lock();

		if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {

			if (!dev || dev == res.fi->fib_dev)

				ret = res.type;

		}

		rcu_read_unlock();

	}



	rcu_read_unlock();

	return ret;

}
@@ -919,7 +918,7 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) 
#undef BRD1_OK

}



static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)

static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)

{



	struct fib_result       res;
@@ -929,6 +928,11 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb) 
		.flowi4_tos = frn->fl_tos,

		.flowi4_scope = frn->fl_scope,

	};

	struct fib_table *tb;



	rcu_read_lock();



	tb = fib_get_table(net, frn->tb_id_in);



	frn->err = -ENOENT;

	if (tb) {
@@ -945,6 +949,8 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb) 
		}

		local_bh_enable();

	}



	rcu_read_unlock();

}



static void nl_fib_input(struct sk_buff *skb)
@@ -952,7 +958,6 @@ static void nl_fib_input(struct sk_buff *skb) 
	struct net *net;

	struct fib_result_nl *frn;

	struct nlmsghdr *nlh;

	struct fib_table *tb;

	u32 portid;



	net = sock_net(skb->sk);
@@ -967,9 +972,7 @@ static void nl_fib_input(struct sk_buff *skb) 
	nlh = nlmsg_hdr(skb);



	frn = (struct fib_result_nl *) nlmsg_data(nlh);

	tb = fib_get_table(net, frn->tb_id_in);



	nl_fib_lookup(frn, tb);

	nl_fib_lookup(net, frn);



	portid = NETLINK_CB(skb).portid;      /* netlink portid */

	NETLINK_CB(skb).portid = 0;        /* from kernel */

net/ipv4/fib_rules.c

+10 −12
Original line number Diff line number Diff line
@@ -81,27 +81,25 @@ static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 
		break;



	case FR_ACT_UNREACHABLE:

		err = -ENETUNREACH;

		goto errout;

		return -ENETUNREACH;



	case FR_ACT_PROHIBIT:

		err = -EACCES;

		goto errout;

		return -EACCES;



	case FR_ACT_BLACKHOLE:

	default:

		err = -EINVAL;

		goto errout;

		return -EINVAL;

	}



	rcu_read_lock();



	tbl = fib_get_table(rule->fr_net, rule->table);

	if (!tbl)

		goto errout;

	if (tbl)

		err = fib_table_lookup(tbl, &flp->u.ip4,

				       (struct fib_result *)arg->result,

				       arg->flags);



	err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags);

	if (err > 0)

		err = -EAGAIN;

errout:

	rcu_read_unlock();

	return err;

}

net/ipv4/fib_trie.c

+60 −77
Original line number Diff line number Diff line
@@ -1181,72 +1181,6 @@ err: 
	return err;

}



/* should be called with rcu_read_lock */

static int check_leaf(struct fib_table *tb, struct trie *t, struct tnode *l,

		      t_key key,  const struct flowi4 *flp,

		      struct fib_result *res, int fib_flags)

{

	struct leaf_info *li;

	struct hlist_head *hhead = &l->list;



	hlist_for_each_entry_rcu(li, hhead, hlist) {

		struct fib_alias *fa;



		if (l->key != (key & li->mask_plen))

			continue;



		list_for_each_entry_rcu(fa, &li->falh, fa_list) {

			struct fib_info *fi = fa->fa_info;

			int nhsel, err;



			if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)

				continue;

			if (fi->fib_dead)

				continue;

			if (fa->fa_info->fib_scope < flp->flowi4_scope)

				continue;

			fib_alias_accessed(fa);

			err = fib_props[fa->fa_type].error;

			if (unlikely(err < 0)) {

#ifdef CONFIG_IP_FIB_TRIE_STATS

				this_cpu_inc(t->stats->semantic_match_passed);

#endif

				return err;

			}

			if (fi->fib_flags & RTNH_F_DEAD)

				continue;

			for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {

				const struct fib_nh *nh = &fi->fib_nh[nhsel];



				if (nh->nh_flags & RTNH_F_DEAD)

					continue;

				if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)

					continue;



#ifdef CONFIG_IP_FIB_TRIE_STATS

				this_cpu_inc(t->stats->semantic_match_passed);

#endif

				res->prefixlen = li->plen;

				res->nh_sel = nhsel;

				res->type = fa->fa_type;

				res->scope = fi->fib_scope;

				res->fi = fi;

				res->table = tb;

				res->fa_head = &li->falh;

				if (!(fib_flags & FIB_LOOKUP_NOREF))

					atomic_inc(&fi->fib_clntref);

				return 0;

			}

		}



#ifdef CONFIG_IP_FIB_TRIE_STATS

		this_cpu_inc(t->stats->semantic_match_miss);

#endif

	}



	return 1;

}



static inline t_key prefix_mismatch(t_key key, struct tnode *n)

{

	t_key prefix = n->key;
@@ -1254,6 +1188,7 @@ static inline t_key prefix_mismatch(t_key key, struct tnode *n) 
	return (key ^ prefix) & (prefix | -prefix);

}



/* should be called with rcu_read_lock */

int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,

		     struct fib_result *res, int fib_flags)

{
@@ -1263,14 +1198,12 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp, 
#endif

	const t_key key = ntohl(flp->daddr);

	struct tnode *n, *pn;

	struct leaf_info *li;

	t_key cindex;

	int ret = 1;



	rcu_read_lock();



	n = rcu_dereference(t->trie);

	if (!n)

		goto failed;

		return -EAGAIN;



#ifdef CONFIG_IP_FIB_TRIE_STATS

	this_cpu_inc(stats->gets);
@@ -1350,7 +1283,7 @@ backtrace: 


				pn = node_parent_rcu(pn);

				if (unlikely(!pn))

					goto failed;

					return -EAGAIN;

#ifdef CONFIG_IP_FIB_TRIE_STATS

				this_cpu_inc(stats->backtrack);

#endif
@@ -1368,12 +1301,62 @@ backtrace: 


found:

	/* Step 3: Process the leaf, if that fails fall back to backtracing */

	ret = check_leaf(tb, t, n, key, flp, res, fib_flags);

	if (unlikely(ret > 0))

	hlist_for_each_entry_rcu(li, &n->list, hlist) {

		struct fib_alias *fa;



		if ((key ^ n->key) & li->mask_plen)

			continue;



		list_for_each_entry_rcu(fa, &li->falh, fa_list) {

			struct fib_info *fi = fa->fa_info;

			int nhsel, err;



			if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)

				continue;

			if (fi->fib_dead)

				continue;

			if (fa->fa_info->fib_scope < flp->flowi4_scope)

				continue;

			fib_alias_accessed(fa);

			err = fib_props[fa->fa_type].error;

			if (unlikely(err < 0)) {

#ifdef CONFIG_IP_FIB_TRIE_STATS

				this_cpu_inc(stats->semantic_match_passed);

#endif

				return err;

			}

			if (fi->fib_flags & RTNH_F_DEAD)

				continue;

			for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {

				const struct fib_nh *nh = &fi->fib_nh[nhsel];



				if (nh->nh_flags & RTNH_F_DEAD)

					continue;

				if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)

					continue;



				if (!(fib_flags & FIB_LOOKUP_NOREF))

					atomic_inc(&fi->fib_clntref);



				res->prefixlen = li->plen;

				res->nh_sel = nhsel;

				res->type = fa->fa_type;

				res->scope = fi->fib_scope;

				res->fi = fi;

				res->table = tb;

				res->fa_head = &li->falh;

#ifdef CONFIG_IP_FIB_TRIE_STATS

				this_cpu_inc(stats->semantic_match_passed);

#endif

				return err;

			}

		}



#ifdef CONFIG_IP_FIB_TRIE_STATS

		this_cpu_inc(stats->semantic_match_miss);

#endif

	}

	goto backtrace;

failed:

	rcu_read_unlock();

	return ret;

}

EXPORT_SYMBOL_GPL(fib_table_lookup);

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