Commit b7d2fc9a authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Paolo Abeni
Browse files

phonet: Don't hold RTNL for getaddr_dumpit(). 



getaddr_dumpit() already relies on RCU and does not need RTNL.

Let's use READ_ONCE() for ifindex and register getaddr_dumpit()
with RTNL_FLAG_DUMP_UNLOCKED.

While at it, the retval of getaddr_dumpit() is changed to combine
NLMSG_DONE and save recvmsg() as done in 58a4ff5d ("phonet: no
longer hold RTNL in route_dumpit()").

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 8786e98d

net/phonet/pn_netlink.c

+15 −9
Original line number Diff line number Diff line
@@ -127,14 +127,17 @@ static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr, 


static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)

{

	int addr_idx = 0, addr_start_idx = cb->args[1];

	int dev_idx = 0, dev_start_idx = cb->args[0];

	struct phonet_device_list *pndevs;

	struct phonet_device *pnd;

	int dev_idx = 0, dev_start_idx = cb->args[0];

	int addr_idx = 0, addr_start_idx = cb->args[1];

	int err = 0;



	pndevs = phonet_device_list(sock_net(skb->sk));



	rcu_read_lock();

	list_for_each_entry_rcu(pnd, &pndevs->list, list) {

		DECLARE_BITMAP(addrs, 64);

		u8 addr;



		if (dev_idx > dev_start_idx)
@@ -143,23 +146,26 @@ static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
			continue;



		addr_idx = 0;

		for_each_set_bit(addr, pnd->addrs, 64) {

		memcpy(addrs, pnd->addrs, sizeof(pnd->addrs));



		for_each_set_bit(addr, addrs, 64) {

			if (addr_idx++ < addr_start_idx)

				continue;



			if (fill_addr(skb, pnd->netdev->ifindex, addr << 2,

					 NETLINK_CB(cb->skb).portid,

					cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0)

			err = fill_addr(skb, READ_ONCE(pnd->netdev->ifindex),

					addr << 2, NETLINK_CB(cb->skb).portid,

					cb->nlh->nlmsg_seq, RTM_NEWADDR);

			if (err < 0)

				goto out;

		}

	}



out:

	rcu_read_unlock();



	cb->args[0] = dev_idx;

	cb->args[1] = addr_idx;



	return skb->len;

	return err;

}



/* Routes handling */
@@ -298,7 +304,7 @@ static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_mo 
	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELADDR,

	 .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR,

	 .dumpit = getaddr_dumpit},

	 .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE,

	 .doit = route_doit},

	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,