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>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 99b58d86217474d1b537d4e9976acf3d6c1d697e..aa963c44450a7e866eaa1c0670dcf36c5f3c147b 100644 (file)
--- 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