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Commit 30a4616c authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

tipc: use rcu dereference functions properly 



For these places are protected by rcu_read_lock, we change from
rcu_dereference_rtnl to rcu_dereference, as there is no need to
check if rtnl lock is held.

For these places are protected by rtnl_lock, we change from
rcu_dereference_rtnl to rtnl_dereference/rcu_dereference_protected,
as no extra memory barriers are needed under rtnl_lock() which also
protects tn->bearer_list[] and dev->tipc_ptr/b->media_ptr updating.

rcu_dereference_rtnl will be only used in the places where it could
be under rcu_read_lock or rtnl_lock.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9e0773c3

net/tipc/bearer.c

+7 −7
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static struct tipc_bearer *bearer_get(struct net *net, int bearer_id) 
{

	struct tipc_net *tn = tipc_net(net);



	return rcu_dereference_rtnl(tn->bearer_list[bearer_id]);

	return rcu_dereference(tn->bearer_list[bearer_id]);

}



static void bearer_disable(struct net *net, struct tipc_bearer *b);
@@ -210,7 +210,7 @@ void tipc_bearer_add_dest(struct net *net, u32 bearer_id, u32 dest) 
	struct tipc_bearer *b;



	rcu_read_lock();

	b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);

	b = rcu_dereference(tn->bearer_list[bearer_id]);

	if (b)

		tipc_disc_add_dest(b->disc);

	rcu_read_unlock();
@@ -222,7 +222,7 @@ void tipc_bearer_remove_dest(struct net *net, u32 bearer_id, u32 dest) 
	struct tipc_bearer *b;



	rcu_read_lock();

	b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]);

	b = rcu_dereference(tn->bearer_list[bearer_id]);

	if (b)

		tipc_disc_remove_dest(b->disc);

	rcu_read_unlock();
@@ -444,7 +444,7 @@ int tipc_l2_send_msg(struct net *net, struct sk_buff *skb, 
	struct net_device *dev;

	int delta;



	dev = (struct net_device *)rcu_dereference_rtnl(b->media_ptr);

	dev = (struct net_device *)rcu_dereference(b->media_ptr);

	if (!dev)

		return 0;
@@ -481,7 +481,7 @@ int tipc_bearer_mtu(struct net *net, u32 bearer_id) 
	struct tipc_bearer *b;



	rcu_read_lock();

	b = rcu_dereference_rtnl(tipc_net(net)->bearer_list[bearer_id]);

	b = rcu_dereference(tipc_net(net)->bearer_list[bearer_id]);

	if (b)

		mtu = b->mtu;

	rcu_read_unlock();
@@ -574,8 +574,8 @@ static int tipc_l2_rcv_msg(struct sk_buff *skb, struct net_device *dev, 
	struct tipc_bearer *b;



	rcu_read_lock();

	b = rcu_dereference_rtnl(dev->tipc_ptr) ?:

		rcu_dereference_rtnl(orig_dev->tipc_ptr);

	b = rcu_dereference(dev->tipc_ptr) ?:

		rcu_dereference(orig_dev->tipc_ptr);

	if (likely(b && test_bit(0, &b->up) &&

		   (skb->pkt_type <= PACKET_MULTICAST))) {

		skb_mark_not_on_list(skb);

net/tipc/udp_media.c

+4 −4
Original line number Diff line number Diff line
@@ -231,7 +231,7 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb, 
	}



	skb_set_inner_protocol(skb, htons(ETH_P_TIPC));

	ub = rcu_dereference_rtnl(b->media_ptr);

	ub = rcu_dereference(b->media_ptr);

	if (!ub) {

		err = -ENODEV;

		goto out;
@@ -490,7 +490,7 @@ int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb) 
		}

	}



	ub = rcu_dereference_rtnl(b->media_ptr);

	ub = rtnl_dereference(b->media_ptr);

	if (!ub) {

		rtnl_unlock();

		return -EINVAL;
@@ -532,7 +532,7 @@ int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b) 
	struct udp_bearer *ub;

	struct nlattr *nest;



	ub = rcu_dereference_rtnl(b->media_ptr);

	ub = rtnl_dereference(b->media_ptr);

	if (!ub)

		return -ENODEV;
@@ -806,7 +806,7 @@ static void tipc_udp_disable(struct tipc_bearer *b) 
{

	struct udp_bearer *ub;



	ub = rcu_dereference_rtnl(b->media_ptr);

	ub = rtnl_dereference(b->media_ptr);

	if (!ub) {

		pr_err("UDP bearer instance not found\n");

		return;