ipv6: make in6_dump_addrs() lockless

in6_dump_addrs() is called with RCU protection.

There is no need holding idev->lock to iterate through unicast addresses.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 5864a1fc6850a74c59dd311c0017b935acaf2eff..c662972d92063b27f589c84b6d64cd4c0e185c17 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5271,23 +5271,22 @@ static int inet6_fill_ifacaddr(struct sk_buff *skb,
 }
 
 /* called with rcu_read_lock() */
-static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb,
+static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
                          struct netlink_callback *cb, int s_ip_idx,
                          struct inet6_fill_args *fillargs)
 {
-       struct ifmcaddr6 *ifmca;
-       struct ifacaddr6 *ifaca;
+       const struct ifmcaddr6 *ifmca;
+       const struct ifacaddr6 *ifaca;
        int ip_idx = 0;
        int err = 1;
 
-       read_lock_bh(&idev->lock);
        switch (fillargs->type) {
        case UNICAST_ADDR: {
-               struct inet6_ifaddr *ifa;
+               const struct inet6_ifaddr *ifa;
                fillargs->event = RTM_NEWADDR;
 
                /* unicast address incl. temp addr */
-               list_for_each_entry(ifa, &idev->addr_list, if_list) {
+               list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
                        if (ip_idx < s_ip_idx)
                                goto next;
                        err = inet6_fill_ifaddr(skb, ifa, fillargs);
@@ -5300,7 +5299,6 @@ next:
                break;
        }
        case MULTICAST_ADDR:
-               read_unlock_bh(&idev->lock);
                fillargs->event = RTM_GETMULTICAST;
 
                /* multicast address */
@@ -5313,7 +5311,6 @@ next:
                        if (err < 0)
                                break;
                }
-               read_lock_bh(&idev->lock);
                break;
        case ANYCAST_ADDR:
                fillargs->event = RTM_GETANYCAST;
@@ -5330,7 +5327,6 @@ next:
        default:
                break;
        }
-       read_unlock_bh(&idev->lock);
        cb->args[2] = ip_idx;
        return err;
 }