Commit dde1b38e authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

mpls: Convert mpls_dump_routes() to RCU. 



mpls_dump_routes() sets fib_dump_filter.rtnl_held to true and
calls __dev_get_by_index() in mpls_valid_fib_dump_req().

This is the only RTNL dependant in mpls_dump_routes().

Also, synchronize_rcu() in resize_platform_label_table()
guarantees that net->mpls.platform_label is alive under RCU.

Let's convert mpls_dump_routes() to RCU and use dev_get_by_index_rcu().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarGuillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20251029173344.2934622-11-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 3a496293

net/mpls/af_mpls.c

+16 −10
Original line number Diff line number Diff line
@@ -2153,7 +2153,7 @@ static int mpls_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh, 


		if (i == RTA_OIF) {

			ifindex = nla_get_u32(tb[i]);

			filter->dev = __dev_get_by_index(net, ifindex);

			filter->dev = dev_get_by_index_rcu(net, ifindex);

			if (!filter->dev)

				return -ENODEV;

			filter->filter_set = 1;
@@ -2191,20 +2191,19 @@ 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;

	struct fib_dump_filter filter = {

		.rtnl_held = true,

		.rtnl_held = false,

	};

	unsigned int flags = NLM_F_MULTI;

	size_t platform_labels;

	unsigned int index;

	int err;



	ASSERT_RTNL();

	rcu_read_lock();



	if (cb->strict_check) {

		int err;



		err = mpls_valid_fib_dump_req(net, nlh, &filter, cb);

		if (err < 0)

			return err;

			goto err;



		/* for MPLS, there is only 1 table with fixed type and flags.

		 * If either are set in the filter then return nothing.
@@ -2212,14 +2211,14 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb) 
		if ((filter.table_id && filter.table_id != RT_TABLE_MAIN) ||

		    (filter.rt_type && filter.rt_type != RTN_UNICAST) ||

		     filter.flags)

			return skb->len;

			goto unlock;

	}



	index = cb->args[0];

	if (index < MPLS_LABEL_FIRST_UNRESERVED)

		index = MPLS_LABEL_FIRST_UNRESERVED;



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

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

	platform_labels = net->mpls.platform_labels;



	if (filter.filter_set)
@@ -2228,7 +2227,7 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb) 
	for (; index < platform_labels; index++) {

		struct mpls_route *rt;



		rt = rtnl_dereference(platform_label[index]);

		rt = rcu_dereference(platform_label[index]);

		if (!rt)

			continue;
@@ -2243,7 +2242,13 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb) 
	}

	cb->args[0] = index;



unlock:

	rcu_read_unlock();

	return skb->len;



err:

	rcu_read_unlock();

	return err;

}



static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
@@ -2767,7 +2772,8 @@ static struct rtnl_af_ops mpls_af_ops __read_mostly = { 
static const struct rtnl_msg_handler mpls_rtnl_msg_handlers[] __initdata_or_module = {

	{THIS_MODULE, PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, 0},

	{THIS_MODULE, PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, 0},

	{THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes, 0},

	{THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes,

	 RTNL_FLAG_DUMP_UNLOCKED},

	{THIS_MODULE, PF_MPLS, RTM_GETNETCONF,

	 mpls_netconf_get_devconf, mpls_netconf_dump_devconf,

	 RTNL_FLAG_DUMP_UNLOCKED},