ip6tnl: less dev_put() calls

Using dev_get_by_index_rcu() in ip6_tnl_rcv_ctl() & ip6_tnl_xmit_ctl()
avoids touching device refcount.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 6c1b5c98e818d0e20424584c088e55adc3ae9daa..1d614113a4ba9afff556e5975917924c92b4b7b5 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -658,6 +658,7 @@ static void ip6ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,
                IP6_ECN_set_ce(ipv6_hdr(skb));
 }
 
+/* called with rcu_read_lock() */
 static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t)
 {
        struct ip6_tnl_parm *p = &t->parms;
@@ -668,15 +669,13 @@ static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t)
                struct net_device *ldev = NULL;
 
                if (p->link)
-                       ldev = dev_get_by_index(net, p->link);
+                       ldev = dev_get_by_index_rcu(net, p->link);
 
                if ((ipv6_addr_is_multicast(&p->laddr) ||
                     likely(ipv6_chk_addr(net, &p->laddr, ldev, 0))) &&
                    likely(!ipv6_chk_addr(net, &p->raddr, NULL, 0)))
                        ret = 1;
 
-               if (ldev)
-                       dev_put(ldev);
        }
        return ret;
 }
@@ -804,8 +803,9 @@ static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
        if (p->flags & IP6_TNL_F_CAP_XMIT) {
                struct net_device *ldev = NULL;
 
+               rcu_read_lock();
                if (p->link)
-                       ldev = dev_get_by_index(net, p->link);
+                       ldev = dev_get_by_index_rcu(net, p->link);
 
                if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0)))
                        printk(KERN_WARNING
@@ -819,8 +819,7 @@ static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
                               p->name);
                else
                        ret = 1;
-               if (ldev)
-                       dev_put(ldev);
+               rcu_read_unlock();
        }
        return ret;
 }