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Commit 19d0c341 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
Browse files

mpls: Cleanup the rcu usage in the code. 



Sparse was generating a lot of warnings mostly from missing annotations
in the code.  Add missing annotations and in a few cases tweak the code
for performance by moving work before loops.

This also fixes a problematic ommision of rcu_assign_pointer and
rcu_dereference.

Hopefully with complete rcu annotations any new rcu errors will stick
out like a sore thumb.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d865616e

net/mpls/af_mpls.c

+47 −26
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ 
#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))



struct mpls_route { /* next hop label forwarding entry */

	struct net_device 	*rt_dev;

	struct net_device __rcu *rt_dev;

	struct rcu_head		rt_rcu;

	u32			rt_label[MAX_NEW_LABELS];

	u8			rt_protocol; /* routing protocol that set this entry */
@@ -152,7 +152,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev, 
		goto drop;



	/* Find the output device */

	out_dev = rt->rt_dev;

	out_dev = rcu_dereference(rt->rt_dev);

	if (!mpls_output_possible(out_dev))

		goto drop;
@@ -269,13 +269,15 @@ static void mpls_route_update(struct net *net, unsigned index, 
			      struct net_device *dev, struct mpls_route *new,

			      const struct nl_info *info)

{

	struct mpls_route __rcu **platform_label;

	struct mpls_route *rt, *old = NULL;



	ASSERT_RTNL();



	rt = net->mpls.platform_label[index];

	if (!dev || (rt && (rt->rt_dev == dev))) {

		rcu_assign_pointer(net->mpls.platform_label[index], new);

	platform_label = rtnl_dereference(net->mpls.platform_label);

	rt = rtnl_dereference(platform_label[index]);

	if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {

		rcu_assign_pointer(platform_label[index], new);

		old = rt;

	}
@@ -287,9 +289,14 @@ static void mpls_route_update(struct net *net, unsigned index, 


static unsigned find_free_label(struct net *net)

{

	struct mpls_route __rcu **platform_label;

	size_t platform_labels;

	unsigned index;

	for (index = 16; index < net->mpls.platform_labels; index++) {

		if (!net->mpls.platform_label[index])



	platform_label = rtnl_dereference(net->mpls.platform_label);

	platform_labels = net->mpls.platform_labels;

	for (index = 16; index < platform_labels; index++) {

		if (!rtnl_dereference(platform_label[index]))

			return index;

	}

	return LABEL_NOT_SPECIFIED;
@@ -297,6 +304,7 @@ static unsigned find_free_label(struct net *net) 


static int mpls_route_add(struct mpls_route_config *cfg)

{

	struct mpls_route __rcu **platform_label;

	struct net *net = cfg->rc_nlinfo.nl_net;

	struct net_device *dev = NULL;

	struct mpls_route *rt, *old;
@@ -345,7 +353,8 @@ static int mpls_route_add(struct mpls_route_config *cfg) 
		goto errout;



	err = -EEXIST;

	old = net->mpls.platform_label[index];

	platform_label = rtnl_dereference(net->mpls.platform_label);

	old = rtnl_dereference(platform_label[index]);

	if ((cfg->rc_nlflags & NLM_F_EXCL) && old)

		goto errout;
@@ -366,7 +375,7 @@ static int mpls_route_add(struct mpls_route_config *cfg) 
	for (i = 0; i < rt->rt_labels; i++)

		rt->rt_label[i] = cfg->rc_output_label[i];

	rt->rt_protocol = cfg->rc_protocol;

	rt->rt_dev = dev;

	RCU_INIT_POINTER(rt->rt_dev, dev);

	rt->rt_via_family = cfg->rc_via_family;

	memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
@@ -406,14 +415,16 @@ static int mpls_route_del(struct mpls_route_config *cfg) 


static void mpls_ifdown(struct net_device *dev)

{

	struct mpls_route __rcu **platform_label;

	struct net *net = dev_net(dev);

	unsigned index;



	platform_label = rtnl_dereference(net->mpls.platform_label);

	for (index = 0; index < net->mpls.platform_labels; index++) {

		struct mpls_route *rt = net->mpls.platform_label[index];

		struct mpls_route *rt = rtnl_dereference(platform_label[index]);

		if (!rt)

			continue;

		if (rt->rt_dev != dev)

		if (rtnl_dereference(rt->rt_dev) != dev)

			continue;

		rt->rt_dev = NULL;

	}
@@ -653,6 +664,7 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh) 
static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,

			   u32 label, struct mpls_route *rt, int flags)

{

	struct net_device *dev;

	struct nlmsghdr *nlh;

	struct rtmsg *rtm;
@@ -676,7 +688,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event, 
		goto nla_put_failure;

	if (nla_put_via(skb, rt->rt_via_family, rt->rt_via, rt->rt_via_alen))

		goto nla_put_failure;

	if (rt->rt_dev && nla_put_u32(skb, RTA_OIF, rt->rt_dev->ifindex))

	dev = rtnl_dereference(rt->rt_dev);

	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))

		goto nla_put_failure;

	if (nla_put_labels(skb, RTA_DST, 1, &label))

		goto nla_put_failure;
@@ -692,6 +705,8 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event, 
static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)

{

	struct net *net = sock_net(skb->sk);

	struct mpls_route __rcu **platform_label;

	size_t platform_labels;

	unsigned int index;



	ASSERT_RTNL();
@@ -700,9 +715,11 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb) 
	if (index < 16)

		index = 16;



	for (; index < net->mpls.platform_labels; index++) {

	platform_label = rtnl_dereference(net->mpls.platform_label);

	platform_labels = net->mpls.platform_labels;

	for (; index < platform_labels; index++) {

		struct mpls_route *rt;

		rt = net->mpls.platform_label[index];

		rt = rtnl_dereference(platform_label[index]);

		if (!rt)

			continue;
@@ -780,7 +797,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) 
		rt0 = mpls_rt_alloc(lo->addr_len);

		if (!rt0)

			goto nort0;

		rt0->rt_dev = lo;

		RCU_INIT_POINTER(rt0->rt_dev, lo);

		rt0->rt_protocol = RTPROT_KERNEL;

		rt0->rt_via_family = AF_PACKET;

		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
@@ -790,7 +807,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) 
		rt2 = mpls_rt_alloc(lo->addr_len);

		if (!rt2)

			goto nort2;

		rt2->rt_dev = lo;

		RCU_INIT_POINTER(rt2->rt_dev, lo);

		rt2->rt_protocol = RTPROT_KERNEL;

		rt2->rt_via_family = AF_PACKET;

		memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
@@ -798,7 +815,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) 


	rtnl_lock();

	/* Remember the original table */

	old = net->mpls.platform_label;

	old = rtnl_dereference(net->mpls.platform_label);

	old_limit = net->mpls.platform_labels;



	/* Free any labels beyond the new table */
@@ -815,19 +832,19 @@ static int resize_platform_label_table(struct net *net, size_t limit) 
	/* If needed set the predefined labels */

	if ((old_limit <= LABEL_IPV6_EXPLICIT_NULL) &&

	    (limit > LABEL_IPV6_EXPLICIT_NULL)) {

		labels[LABEL_IPV6_EXPLICIT_NULL] = rt2;

		RCU_INIT_POINTER(labels[LABEL_IPV6_EXPLICIT_NULL], rt2);

		rt2 = NULL;

	}



	if ((old_limit <= LABEL_IPV4_EXPLICIT_NULL) &&

	    (limit > LABEL_IPV4_EXPLICIT_NULL)) {

		labels[LABEL_IPV4_EXPLICIT_NULL] = rt0;

		RCU_INIT_POINTER(labels[LABEL_IPV4_EXPLICIT_NULL], rt0);

		rt0 = NULL;

	}



	/* Update the global pointers */

	net->mpls.platform_labels = limit;

	net->mpls.platform_label = labels;

	rcu_assign_pointer(net->mpls.platform_label, labels);



	rtnl_unlock();
@@ -903,6 +920,8 @@ static int mpls_net_init(struct net *net) 


static void mpls_net_exit(struct net *net)

{

	struct mpls_route __rcu **platform_label;

	size_t platform_labels;

	struct ctl_table *table;

	unsigned int index;
@@ -910,8 +929,8 @@ static void mpls_net_exit(struct net *net) 
	unregister_net_sysctl_table(net->mpls.ctl);

	kfree(table);



	/* An rcu grace period haselapsed since there was a device in

	 * the network namespace (and thus the last in fqlight packet)

	/* An rcu grace period has passed since there was a device in

	 * the network namespace (and thus the last in flight packet)

	 * left this network namespace.  This is because

	 * unregister_netdevice_many and netdev_run_todo has completed

	 * for each network device that was in this network namespace.
@@ -920,14 +939,16 @@ static void mpls_net_exit(struct net *net) 
	 * freeing the platform_label table.

	 */

	rtnl_lock();

	for (index = 0; index < net->mpls.platform_labels; index++) {

		struct mpls_route *rt = net->mpls.platform_label[index];

		rcu_assign_pointer(net->mpls.platform_label[index], NULL);

	platform_label = rtnl_dereference(net->mpls.platform_label);

	platform_labels = net->mpls.platform_labels;

	for (index = 0; index < platform_labels; index++) {

		struct mpls_route *rt = rtnl_dereference(platform_label[index]);

		RCU_INIT_POINTER(platform_label[index], NULL);

		mpls_rt_free(rt);

	}

	rtnl_unlock();



	kvfree(net->mpls.platform_label);

	kvfree(platform_label);

}



static struct pernet_operations mpls_net_ops = {