pppoe: RCU locking in get_item_by_addr()

Use dev_get_by_name_rcu() instead of dev_get_by_name(),
to avoid touching device refcount in hotpath.

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

1 files changed, 9 insertions, 10 deletions

diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 2559991eea6a..60c8d233209f 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -250,20 +250,19 @@ static inline struct pppox_sock *get_item_by_addr(struct net *net,
 {
         struct net_device *dev;
         struct pppoe_net *pn;
-        struct pppox_sock *pppox_sock;
+        struct pppox_sock *pppox_sock = NULL;
 
         int ifindex;
 
-        dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
-        if (!dev)
-                return NULL;
-
-        ifindex = dev->ifindex;
-        pn = net_generic(net, pppoe_net_id);
-        pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
+        rcu_read_lock();
+        dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
+        if (dev) {
+                ifindex = dev->ifindex;
+                pn = net_generic(net, pppoe_net_id);
+                pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
                                 sp->sa_addr.pppoe.remote, ifindex);
-        dev_put(dev);
-
+        }
+        rcu_read_unlock();
         return pppox_sock;
 }