[RTNETLINK]: Remove unnecessary locking in dump callbacks

Since we're now holding the rtnl during the entire dump operation, we can
remove additional locking for rtnl protected data. This patch does that
for all simple cases (dev_base_lock for dev_base walking, RCU protection
for FIB rule dumping).

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 10 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 9bdc79564cc6..088888db8b3d 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1182,17 +1182,13 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
         int s_ip_idx, s_idx = cb->args[0];
 
         s_ip_idx = ip_idx = cb->args[1];
-        read_lock(&dev_base_lock);
         for (dev = dev_base, idx = 0; dev; dev = dev->next, idx++) {
                 if (idx < s_idx)
                         continue;
                 if (idx > s_idx)
                         s_ip_idx = 0;
-                rcu_read_lock();
-                if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
-                        rcu_read_unlock();
+                if ((in_dev = __in_dev_get_rtnl(dev)) == NULL)
                         continue;
-                }
 
                 for (ifa = in_dev->ifa_list, ip_idx = 0; ifa;
                      ifa = ifa->ifa_next, ip_idx++) {
@@ -1200,16 +1196,12 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
                                 continue;
                         if (inet_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).pid,
                                              cb->nlh->nlmsg_seq,
-                                             RTM_NEWADDR, NLM_F_MULTI) <= 0) {
-                                rcu_read_unlock();
+                                             RTM_NEWADDR, NLM_F_MULTI) <= 0)
                                 goto done;
-                        }
                 }
-                rcu_read_unlock();
         }
 
 done:
-        read_unlock(&dev_base_lock);
         cb->args[0] = idx;
         cb->args[1] = ip_idx;