tun: only queue packets on device

[~andy/linux] / drivers / net / tun.c

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3bd9932a8cded615fa68aea2a809bd465263e05e..a1b2389e6d7fdacce6abb7b3b1ed7d24a2029d05 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -121,11 +121,11 @@ struct tap_filter {
  * also contains all socket related strctures (except sock_fprog and tap_filter)
  * to serve as one transmit queue for tuntap device. The sock_fprog and
  * tap_filter were kept in tun_struct since they were used for filtering for the
- * netdevice not for a specific queue (at least I didn't see the reqirement for
+ * netdevice not for a specific queue (at least I didn't see the requirement for
  * this).
  *
  * RCU usage:
- * The tun_file and tun_struct are loosely coupled, the pointer from on to the
+ * The tun_file and tun_struct are loosely coupled, the pointer from one to the
  * other can only be read while rcu_read_lock or rtnl_lock is held.
  */
 struct tun_file {
@@ -153,7 +153,7 @@ struct tun_flow_entry {
 #define TUN_NUM_FLOW_ENTRIES 1024
 
 /* Since the socket were moved to tun_file, to preserve the behavior of persist
- * device, socket fileter, sndbuf and vnet header size were restore when the
+ * device, socket filter, sndbuf and vnet header size were restore when the
  * file were attached to a persist device.
  */
 struct tun_struct {
@@ -493,9 +493,6 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
 
        tun_set_real_num_queues(tun);
 
-       if (tun->numqueues == 1)
-               netif_carrier_on(tun->dev);
-
        /* device is allowed to go away first, so no need to hold extra
         * refcnt.
         */
@@ -689,25 +686,12 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
            sk_filter(tfile->socket.sk, skb))
                goto drop;
 
-       /* Limit the number of packets queued by divining txq length with the
+       /* Limit the number of packets queued by dividing txq length with the
         * number of queues.
         */
        if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
-                         >= dev->tx_queue_len / tun->numqueues){
-               if (!(tun->flags & TUN_ONE_QUEUE)) {
-                       /* Normal queueing mode. */
-                       /* Packet scheduler handles dropping of further packets. */
-                       netif_stop_subqueue(dev, txq);
-
-                       /* We won't see all dropped packets individually, so overrun
-                        * error is more appropriate. */
-                       dev->stats.tx_fifo_errors++;
-               } else {
-                       /* Single queue mode.
-                        * Driver handles dropping of all packets itself. */
-                       goto drop;
-               }
-       }
+                         >= dev->tx_queue_len / tun->numqueues)
+               goto drop;
 
        /* Orphan the skb - required as we might hang on to it
         * for indefinite time. */
@@ -1296,7 +1280,7 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
        struct sk_buff *skb;
        ssize_t ret = 0;
 
-       tun_debug(KERN_INFO, tun, "tun_chr_read\n");
+       tun_debug(KERN_INFO, tun, "tun_do_read\n");
 
        if (unlikely(!noblock))
                add_wait_queue(&tfile->wq.wait, &wait);
@@ -1322,7 +1306,6 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
                        schedule();
                        continue;
                }
-               netif_wake_subqueue(tun->dev, tfile->queue_index);
 
                ret = tun_put_user(tun, tfile, skb, iv, len);
                kfree_skb(skb);
@@ -1485,6 +1468,9 @@ static int tun_flags(struct tun_struct *tun)
        if (tun->flags & TUN_NO_PI)
                flags |= IFF_NO_PI;
 
+       /* This flag has no real effect.  We track the value for backwards
+        * compatibility.
+        */
        if (tun->flags & TUN_ONE_QUEUE)
                flags |= IFF_ONE_QUEUE;
 
@@ -1612,6 +1598,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                        TUN_USER_FEATURES;
                dev->features = dev->hw_features;
 
+               err = tun_attach(tun, file);
+               if (err < 0)
+                       goto err_free_dev;
+
                err = register_netdevice(tun->dev);
                if (err < 0)
                        goto err_free_dev;
@@ -1621,9 +1611,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                    device_create_file(&tun->dev->dev, &dev_attr_group))
                        pr_err("Failed to create tun sysfs files\n");
 
-               err = tun_attach(tun, file);
-               if (err < 0)
-                       goto err_free_dev;
+               netif_carrier_on(tun->dev);
        }
 
        tun_debug(KERN_INFO, tun, "tun_set_iff\n");
@@ -1633,6 +1621,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
        else
                tun->flags &= ~TUN_NO_PI;
 
+       /* This flag has no real effect.  We track the value for backwards
+        * compatibility.
+        */
        if (ifr->ifr_flags & IFF_ONE_QUEUE)
                tun->flags |= TUN_ONE_QUEUE;
        else