tuntap: fix ambigious multiqueue API

[linux-2.6-block.git] / drivers / net / tun.c

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 2ac2164a1e39bd70b0a046ee6dc7df05b76e1045..255a9f574869fd6d4fc09a0cf3f9a80ca7c1d7fd 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -138,6 +138,8 @@ struct tun_file {
        /* only used for fasnyc */
        unsigned int flags;
        u16 queue_index;
+       struct list_head next;
+       struct tun_struct *detached;
 };
 
 struct tun_flow_entry {
@@ -182,6 +184,8 @@ struct tun_struct {
        struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
        struct timer_list flow_gc_timer;
        unsigned long ageing_time;
+       unsigned int numdisabled;
+       struct list_head disabled;
 };
 
 static inline u32 tun_hashfn(u32 rxhash)
@@ -297,13 +301,12 @@ static void tun_flow_cleanup(unsigned long data)
        spin_unlock_bh(&tun->lock);
 }
 
-static void tun_flow_update(struct tun_struct *tun, struct sk_buff *skb,
+static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
                            u16 queue_index)
 {
        struct hlist_head *head;
        struct tun_flow_entry *e;
        unsigned long delay = tun->ageing_time;
-       u32 rxhash = skb_get_rxhash(skb);
 
        if (!rxhash)
                return;
@@ -386,6 +389,23 @@ static void tun_set_real_num_queues(struct tun_struct *tun)
        netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
 }
 
+static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
+{
+       tfile->detached = tun;
+       list_add_tail(&tfile->next, &tun->disabled);
+       ++tun->numdisabled;
+}
+
+struct tun_struct *tun_enable_queue(struct tun_file *tfile)
+{
+       struct tun_struct *tun = tfile->detached;
+
+       tfile->detached = NULL;
+       list_del_init(&tfile->next);
+       --tun->numdisabled;
+       return tun;
+}
+
 static void __tun_detach(struct tun_file *tfile, bool clean)
 {
        struct tun_file *ntfile;
@@ -407,20 +427,25 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
                ntfile->queue_index = index;
 
                --tun->numqueues;
-               sock_put(&tfile->sk);
+               if (clean)
+                       sock_put(&tfile->sk);
+               else
+                       tun_disable_queue(tun, tfile);
 
                synchronize_net();
                tun_flow_delete_by_queue(tun, tun->numqueues + 1);
                /* Drop read queue */
                skb_queue_purge(&tfile->sk.sk_receive_queue);
                tun_set_real_num_queues(tun);
-
-               if (tun->numqueues == 0 && !(tun->flags & TUN_PERSIST))
-                       if (dev->reg_state == NETREG_REGISTERED)
-                               unregister_netdevice(dev);
-       }
+       } else if (tfile->detached && clean)
+               tun = tun_enable_queue(tfile);
 
        if (clean) {
+               if (tun && tun->numqueues == 0 && tun->numdisabled == 0 &&
+                   !(tun->flags & TUN_PERSIST))
+                       if (tun->dev->reg_state == NETREG_REGISTERED)
+                               unregister_netdevice(tun->dev);
+
                BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
                                 &tfile->socket.flags));
                sk_release_kernel(&tfile->sk);
@@ -437,7 +462,7 @@ static void tun_detach(struct tun_file *tfile, bool clean)
 static void tun_detach_all(struct net_device *dev)
 {
        struct tun_struct *tun = netdev_priv(dev);
-       struct tun_file *tfile;
+       struct tun_file *tfile, *tmp;
        int i, n = tun->numqueues;
 
        for (i = 0; i < n; i++) {
@@ -458,6 +483,12 @@ static void tun_detach_all(struct net_device *dev)
                skb_queue_purge(&tfile->sk.sk_receive_queue);
                sock_put(&tfile->sk);
        }
+       list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
+               tun_enable_queue(tfile);
+               skb_queue_purge(&tfile->sk.sk_receive_queue);
+               sock_put(&tfile->sk);
+       }
+       BUG_ON(tun->numdisabled != 0);
 }
 
 static int tun_attach(struct tun_struct *tun, struct file *file)
@@ -474,7 +505,8 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
                goto out;
 
        err = -E2BIG;
-       if (tun->numqueues == MAX_TAP_QUEUES)
+       if (!tfile->detached &&
+           tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
                goto out;
 
        err = 0;
@@ -488,9 +520,13 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
        tfile->queue_index = tun->numqueues;
        rcu_assign_pointer(tfile->tun, tun);
        rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
-       sock_hold(&tfile->sk);
        tun->numqueues++;
 
+       if (tfile->detached)
+               tun_enable_queue(tfile);
+       else
+               sock_hold(&tfile->sk);
+
        tun_set_real_num_queues(tun);
 
        /* device is allowed to go away first, so no need to hold extra
@@ -1010,6 +1046,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
        int copylen;
        bool zerocopy = false;
        int err;
+       u32 rxhash;
 
        if (!(tun->flags & TUN_NO_PI)) {
                if ((len -= sizeof(pi)) > total_len)
@@ -1162,12 +1199,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
                skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
        }
 
+       rxhash = skb_get_rxhash(skb);
        netif_rx_ni(skb);
 
        tun->dev->stats.rx_packets++;
        tun->dev->stats.rx_bytes += len;
 
-       tun_flow_update(tun, skb, tfile->queue_index);
+       tun_flow_update(tun, rxhash, tfile->queue_index);
        return total_len;
 }
 
@@ -1348,6 +1386,7 @@ static void tun_free_netdev(struct net_device *dev)
 {
        struct tun_struct *tun = netdev_priv(dev);
 
+       BUG_ON(!(list_empty(&tun->disabled)));
        tun_flow_uninit(tun);
        free_netdev(dev);
 }
@@ -1542,6 +1581,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                err = tun_attach(tun, file);
                if (err < 0)
                        return err;
+
+               if (tun->flags & TUN_TAP_MQ &&
+                   (tun->numqueues + tun->numdisabled > 1))
+                       return err;
        }
        else {
                char *name;
@@ -1600,6 +1643,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                        TUN_USER_FEATURES;
                dev->features = dev->hw_features;
 
+               INIT_LIST_HEAD(&tun->disabled);
                err = tun_attach(tun, file);
                if (err < 0)
                        goto err_free_dev;
@@ -1754,32 +1798,28 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr)
 {
        struct tun_file *tfile = file->private_data;
        struct tun_struct *tun;
-       struct net_device *dev;
        int ret = 0;
 
        rtnl_lock();
 
        if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
-               dev = __dev_get_by_name(tfile->net, ifr->ifr_name);
-               if (!dev) {
-                       ret = -EINVAL;
-                       goto unlock;
-               }
-
-               tun = netdev_priv(dev);
-               if (dev->netdev_ops != &tap_netdev_ops &&
-                       dev->netdev_ops != &tun_netdev_ops)
+               tun = tfile->detached;
+               if (!tun)
                        ret = -EINVAL;
                else if (tun_not_capable(tun))
                        ret = -EPERM;
                else
                        ret = tun_attach(tun, file);
-       } else if (ifr->ifr_flags & IFF_DETACH_QUEUE)
-               __tun_detach(tfile, false);
-       else
+       } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
+               tun = rcu_dereference_protected(tfile->tun,
+                                               lockdep_rtnl_is_held());
+               if (!tun || !(tun->flags & TUN_TAP_MQ))
+                       ret = -EINVAL;
+               else
+                       __tun_detach(tfile, false);
+       } else
                ret = -EINVAL;
 
-unlock:
        rtnl_unlock();
        return ret;
 }
@@ -2091,6 +2131,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
 
        file->private_data = tfile;
        set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
+       INIT_LIST_HEAD(&tfile->next);
 
        return 0;
 }