tuntap: switch to use rtnl_dereference()

Switch to use rtnl_dereference() instead of the open code, suggested by Eric.

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

1 files changed, 10 insertions, 17 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 99b58d862174..aa963c44450a 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -404,8 +404,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
         struct tun_struct *tun;
         struct net_device *dev;
 
-        tun = rcu_dereference_protected(tfile->tun,
-                                        lockdep_rtnl_is_held());
+        tun = rtnl_dereference(tfile->tun);
+
         if (tun) {
                 u16 index = tfile->queue_index;
                 BUG_ON(index >= tun->numqueues);
@@ -414,8 +414,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
                 rcu_assign_pointer(tun->tfiles[index],
                                    tun->tfiles[tun->numqueues - 1]);
                 rcu_assign_pointer(tfile->tun, NULL);
-                ntfile = rcu_dereference_protected(tun->tfiles[index],
-                                                   lockdep_rtnl_is_held());
+                ntfile = rtnl_dereference(tun->tfiles[index]);
                 ntfile->queue_index = index;
 
                 --tun->numqueues;
@@ -458,8 +457,7 @@ static void tun_detach_all(struct net_device *dev)
         int i, n = tun->numqueues;
 
         for (i = 0; i < n; i++) {
-                tfile = rcu_dereference_protected(tun->tfiles[i],
-                                                  lockdep_rtnl_is_held());
+                tfile = rtnl_dereference(tun->tfiles[i]);
                 BUG_ON(!tfile);
                 wake_up_all(&tfile->wq.wait);
                 rcu_assign_pointer(tfile->tun, NULL);
@@ -469,8 +467,7 @@ static void tun_detach_all(struct net_device *dev)
 
         synchronize_net();
         for (i = 0; i < n; i++) {
-                tfile = rcu_dereference_protected(tun->tfiles[i],
-                                                  lockdep_rtnl_is_held());
+                tfile = rtnl_dereference(tun->tfiles[i]);
                 /* Drop read queue */
                 skb_queue_purge(&tfile->sk.sk_receive_queue);
                 sock_put(&tfile->sk);
@@ -489,7 +486,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
         int err;
 
         err = -EINVAL;
-        if (rcu_dereference_protected(tfile->tun, lockdep_rtnl_is_held()))
+        if (rtnl_dereference(tfile->tun))
                 goto out;
         if (tfile->detached && tun != tfile->detached)
                 goto out;
@@ -1740,8 +1737,7 @@ static void tun_detach_filter(struct tun_struct *tun, int n)
         struct tun_file *tfile;
 
         for (i = 0; i < n; i++) {
-                tfile = rcu_dereference_protected(tun->tfiles[i],
-                                                  lockdep_rtnl_is_held());
+                tfile = rtnl_dereference(tun->tfiles[i]);
                 sk_detach_filter(tfile->socket.sk);
         }
 
@@ -1754,8 +1750,7 @@ static int tun_attach_filter(struct tun_struct *tun)
         struct tun_file *tfile;
 
         for (i = 0; i < tun->numqueues; i++) {
-                tfile = rcu_dereference_protected(tun->tfiles[i],
-                                                  lockdep_rtnl_is_held());
+                tfile = rtnl_dereference(tun->tfiles[i]);
                 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
                 if (ret) {
                         tun_detach_filter(tun, i);
@@ -1773,8 +1768,7 @@ static void tun_set_sndbuf(struct tun_struct *tun)
         int i;
 
         for (i = 0; i < tun->numqueues; i++) {
-                tfile = rcu_dereference_protected(tun->tfiles[i],
-                                                lockdep_rtnl_is_held());
+                tfile = rtnl_dereference(tun->tfiles[i]);
                 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
         }
 }
@@ -1794,8 +1788,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr)
                 else
                         ret = tun_attach(tun, file);
         } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
-                tun = rcu_dereference_protected(tfile->tun,
-                                                lockdep_rtnl_is_held());
+                tun = rtnl_dereference(tfile->tun);
                 if (!tun || !(tun->flags & TUN_TAP_MQ))
                         ret = -EINVAL;
                 else