Commit cdb2f80f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

inet: use xa_array iterator to implement inet_dump_ifaddr() 



1) inet_dump_ifaddr() can can run under RCU protection
   instead of RTNL.

2) properly return 0 at the end of a dump, avoiding an
   an extra recvmsg() system call.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 590e92cd

net/ipv4/devinet.c

+37 −58
Original line number Diff line number Diff line
@@ -1676,7 +1676,7 @@ static int put_cacheinfo(struct sk_buff *skb, unsigned long cstamp, 
	return nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci);

}



static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,

static int inet_fill_ifaddr(struct sk_buff *skb, const struct in_ifaddr *ifa,

			    struct inet_fill_args *args)

{

	struct ifaddrmsg *ifm;
@@ -1805,15 +1805,15 @@ static int inet_valid_dump_ifaddr_req(const struct nlmsghdr *nlh, 
}



static int in_dev_dump_addr(struct in_device *in_dev, struct sk_buff *skb,

			    struct netlink_callback *cb, int s_ip_idx,

			    struct netlink_callback *cb, int *s_ip_idx,

			    struct inet_fill_args *fillargs)

{

	struct in_ifaddr *ifa;

	int ip_idx = 0;

	int err;



	in_dev_for_each_ifa_rtnl(ifa, in_dev) {

		if (ip_idx < s_ip_idx) {

	in_dev_for_each_ifa_rcu(ifa, in_dev) {

		if (ip_idx < *s_ip_idx) {

			ip_idx++;

			continue;

		}
@@ -1825,9 +1825,9 @@ static int in_dev_dump_addr(struct in_device *in_dev, struct sk_buff *skb, 
		ip_idx++;

	}

	err = 0;



	ip_idx = 0;

done:

	cb->args[2] = ip_idx;

	*s_ip_idx = ip_idx;



	return err;

}
@@ -1859,75 +1859,53 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb) 
	};

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

	struct net *tgt_net = net;

	int h, s_h;

	int idx, s_idx;

	int s_ip_idx;

	struct net_device *dev;

	struct {

		unsigned long ifindex;

		int ip_idx;

	} *ctx = (void *)cb->ctx;

	struct in_device *in_dev;

	struct hlist_head *head;

	struct net_device *dev;

	int err = 0;



	s_h = cb->args[0];

	s_idx = idx = cb->args[1];

	s_ip_idx = cb->args[2];



	rcu_read_lock();

	if (cb->strict_check) {

		err = inet_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net,

						 skb->sk, cb);

		if (err < 0)

			goto put_tgt_net;

			goto done;



		err = 0;

		if (fillargs.ifindex) {

			dev = __dev_get_by_index(tgt_net, fillargs.ifindex);

			if (!dev) {

			err = -ENODEV;

				goto put_tgt_net;

			}



			in_dev = __in_dev_get_rtnl(dev);

			if (in_dev) {

				err = in_dev_dump_addr(in_dev, skb, cb, s_ip_idx,

			dev = dev_get_by_index_rcu(tgt_net, fillargs.ifindex);

			if (!dev)

				goto done;

			in_dev = __in_dev_get_rcu(dev);

			if (!in_dev)

				goto done;

			err = in_dev_dump_addr(in_dev, skb, cb, &ctx->ip_idx,

					       &fillargs);

			}

			goto put_tgt_net;

			goto done;

		}

	}



	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {

		idx = 0;

		head = &tgt_net->dev_index_head[h];

		rcu_read_lock();

	cb->seq = inet_base_seq(tgt_net);

		hlist_for_each_entry_rcu(dev, head, index_hlist) {

			if (idx < s_idx)

				goto cont;

			if (h > s_h || idx > s_idx)

				s_ip_idx = 0;



	for_each_netdev_dump(net, dev, ctx->ifindex) {

		in_dev = __in_dev_get_rcu(dev);

		if (!in_dev)

				goto cont;



			err = in_dev_dump_addr(in_dev, skb, cb, s_ip_idx,

			continue;

		err = in_dev_dump_addr(in_dev, skb, cb, &ctx->ip_idx,

				       &fillargs);

			if (err < 0) {

				rcu_read_unlock();

		if (err < 0)

			goto done;

	}

cont:

			idx++;

		}

		rcu_read_unlock();

	}



done:

	cb->args[0] = h;

	cb->args[1] = idx;

put_tgt_net:

	if (err < 0 && likely(skb->len))

		err = skb->len;

	if (fillargs.netnsid >= 0)

		put_net(tgt_net);



	return skb->len ? : err;

	rcu_read_unlock();

	return err;

}



static void rtmsg_ifa(int event, struct in_ifaddr *ifa, struct nlmsghdr *nlh,
@@ -2818,7 +2796,8 @@ void __init devinet_init(void) 


	rtnl_register(PF_INET, RTM_NEWADDR, inet_rtm_newaddr, NULL, 0);

	rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, 0);

	rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0);

	rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr,

		      RTNL_FLAG_DUMP_UNLOCKED);

	rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,

		      inet_netconf_dump_devconf,

		      RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED);