1 files changed, 104 insertions, 52 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8743de9d2572..d3a665d2f7b8 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -87,9 +87,13 @@ struct tap_filter {
         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 };
 
+struct tun_file {
+        struct tun_struct *tun;
+};
+
 struct tun_struct {
+        struct tun_file         *tfile;
         unsigned int            flags;
-        int                     attached;
         uid_t                   owner;
         gid_t                   group;
 
@@ -108,14 +112,15 @@ struct tun_struct {
 
 static int tun_attach(struct tun_struct *tun, struct file *file)
 {
+        struct tun_file *tfile = file->private_data;
         const struct cred *cred = current_cred();
 
         ASSERT_RTNL();
 
-        if (file->private_data)
+        if (tfile->tun)
                 return -EINVAL;
 
-        if (tun->attached)
+        if (tun->tfile)
                 return -EBUSY;
 
         /* Check permissions */
@@ -124,13 +129,41 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
                 !capable(CAP_NET_ADMIN))
                 return -EPERM;
 
-        file->private_data = tun;
-        tun->attached = 1;
+        tfile->tun = tun;
+        tun->tfile = tfile;
         get_net(dev_net(tun->dev));
 
         return 0;
 }
 
+static void __tun_detach(struct tun_struct *tun)
+{
+        struct tun_file *tfile = tun->tfile;
+
+        /* Detach from net device */
+        tfile->tun = NULL;
+        tun->tfile = NULL;
+        put_net(dev_net(tun->dev));
+
+        /* Drop read queue */
+        skb_queue_purge(&tun->readq);
+}
+
+static struct tun_struct *__tun_get(struct tun_file *tfile)
+{
+        return tfile->tun;
+}
+
+static struct tun_struct *tun_get(struct file *file)
+{
+        return __tun_get(file->private_data);
+}
+
+static void tun_put(struct tun_struct *tun)
+{
+        /* Noop for now */
+}
+
 /* TAP filterting */
 static void addr_hash_set(u32 *mask, const u8 *addr)
 {
@@ -261,7 +294,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 
         /* Drop packet if interface is not attached */
-        if (!tun->attached)
+        if (!tun->tfile)
                 goto drop;
 
         /* Drop if the filter does not like it.
@@ -378,7 +411,7 @@ static void tun_net_init(struct net_device *dev)
 /* Poll */
 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 {
-        struct tun_struct *tun = file->private_data;
+        struct tun_struct *tun = tun_get(file);
         unsigned int mask = POLLOUT | POLLWRNORM;
 
         if (!tun)
@@ -391,6 +424,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
         if (!skb_queue_empty(&tun->readq))
                 mask |= POLLIN | POLLRDNORM;
 
+        tun_put(tun);
         return mask;
 }
 
@@ -575,14 +609,18 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
                               unsigned long count, loff_t pos)
 {
-        struct tun_struct *tun = iocb->ki_filp->private_data;
+        struct tun_struct *tun = tun_get(iocb->ki_filp);
+        ssize_t result;
 
         if (!tun)
                 return -EBADFD;
 
         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 
-        return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
+        result = tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
+
+        tun_put(tun);
+        return result;
 }
 
 /* Put packet to the user space buffer */
@@ -655,7 +693,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                             unsigned long count, loff_t pos)
 {
         struct file *file = iocb->ki_filp;
-        struct tun_struct *tun = file->private_data;
+        struct tun_struct *tun = tun_get(file);
         DECLARE_WAITQUEUE(wait, current);
         struct sk_buff *skb;
         ssize_t len, ret = 0;
@@ -666,8 +704,10 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 
         len = iov_length(iv, count);
-        if (len < 0)
-                return -EINVAL;
+        if (len < 0) {
+                ret = -EINVAL;
+                goto out;
+        }
 
         add_wait_queue(&tun->read_wait, &wait);
         while (len) {
@@ -698,6 +738,8 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
         current->state = TASK_RUNNING;
         remove_wait_queue(&tun->read_wait, &wait);
 
+out:
+        tun_put(tun);
         return ret;
 }
 
@@ -822,7 +864,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 {
-        struct tun_struct *tun = file->private_data;
+        struct tun_struct *tun = tun_get(file);
 
         if (!tun)
                 return -EBADFD;
@@ -847,6 +889,7 @@ static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
         if (tun->flags & TUN_VNET_HDR)
                 ifr->ifr_flags |= IFF_VNET_HDR;
 
+        tun_put(tun);
         return 0;
 }
 
@@ -893,7 +936,7 @@ static int set_offload(struct net_device *dev, unsigned long arg)
 static int tun_chr_ioctl(struct inode *inode, struct file *file,
                          unsigned int cmd, unsigned long arg)
 {
-        struct tun_struct *tun = file->private_data;
+        struct tun_struct *tun;
         void __user* argp = (void __user*)arg;
         struct ifreq ifr;
         int ret;
@@ -902,6 +945,16 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                 if (copy_from_user(&ifr, argp, sizeof ifr))
                         return -EFAULT;
 
+        if (cmd == TUNGETFEATURES) {
+                /* Currently this just means: "what IFF flags are valid?".
+                 * This is needed because we never checked for invalid flags on
+                 * TUNSETIFF. */
+                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
+                                IFF_VNET_HDR,
+                                (unsigned int __user*)argp);
+        }
+
+        tun = tun_get(file);
         if (cmd == TUNSETIFF && !tun) {
                 int err;
 
@@ -919,28 +972,21 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                 return 0;
         }
 
-        if (cmd == TUNGETFEATURES) {
-                /* Currently this just means: "what IFF flags are valid?".
-                 * This is needed because we never checked for invalid flags on
-                 * TUNSETIFF. */
-                return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
-                                IFF_VNET_HDR,
-                                (unsigned int __user*)argp);
-        }
 
         if (!tun)
                 return -EBADFD;
 
         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 
+        ret = 0;
         switch (cmd) {
         case TUNGETIFF:
                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
                 if (ret)
-                        return ret;
+                        break;
 
                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
-                        return -EFAULT;
+                        ret = -EFAULT;
                 break;
 
         case TUNSETNOCSUM:
@@ -992,7 +1038,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                         ret = 0;
                 }
                 rtnl_unlock();
-                return ret;
+                break;
 
 #ifdef TUN_DEBUG
         case TUNSETDEBUG:
@@ -1003,24 +1049,25 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                 rtnl_lock();
                 ret = set_offload(tun->dev, arg);
                 rtnl_unlock();
-                return ret;
+                break;
 
         case TUNSETTXFILTER:
                 /* Can be set only for TAPs */
+                ret = -EINVAL;
                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
-                        return -EINVAL;
+                        break;
                 rtnl_lock();
                 ret = update_filter(&tun->txflt, (void __user *)arg);
                 rtnl_unlock();
-                return ret;
+                break;
 
         case SIOCGIFHWADDR:
                 /* Get hw addres */
                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
                 if (copy_to_user(argp, &ifr, sizeof ifr))
-                        return -EFAULT;
-                return 0;
+                        ret = -EFAULT;
+                break;
 
         case SIOCSIFHWADDR:
                 /* Set hw address */
@@ -1030,18 +1077,19 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                 rtnl_lock();
                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
                 rtnl_unlock();
-                return ret;
-
+                break;
         default:
-                return -EINVAL;
+                ret = -EINVAL;
+                break;
         };
 
-        return 0;
+        tun_put(tun);
+        return ret;
 }
 
 static int tun_chr_fasync(int fd, struct file *file, int on)
 {
-        struct tun_struct *tun = file->private_data;
+        struct tun_struct *tun = tun_get(file);
         int ret;
 
         if (!tun)
@@ -1063,40 +1111,44 @@ static int tun_chr_fasync(int fd, struct file *file, int on)
         ret = 0;
 out:
         unlock_kernel();
+        tun_put(tun);
         return ret;
 }
 
 static int tun_chr_open(struct inode *inode, struct file * file)
 {
+        struct tun_file *tfile;
         cycle_kernel_lock();
         DBG1(KERN_INFO "tunX: tun_chr_open\n");
-        file->private_data = NULL;
+
+        tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
+        if (!tfile)
+                return -ENOMEM;
+        tfile->tun = NULL;
+        file->private_data = tfile;
         return 0;
 }
 
 static int tun_chr_close(struct inode *inode, struct file *file)
 {
-        struct tun_struct *tun = file->private_data;
-
-        if (!tun)
-                return 0;
+        struct tun_file *tfile = file->private_data;
+        struct tun_struct *tun = __tun_get(tfile);
 
-        DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 
-        rtnl_lock();
+        if (tun) {
+                DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 
-        /* Detach from net device */
-        file->private_data = NULL;
-        tun->attached = 0;
-        put_net(dev_net(tun->dev));
+                rtnl_lock();
+                __tun_detach(tun);
 
-        /* Drop read queue */
-        skb_queue_purge(&tun->readq);
+                /* If desireable, unregister the netdevice. */
+                if (!(tun->flags & TUN_PERSIST))
+                        unregister_netdevice(tun->dev);
 
-        if (!(tun->flags & TUN_PERSIST))
-                unregister_netdevice(tun->dev);
+                rtnl_unlock();
+        }
 
-        rtnl_unlock();
+        kfree(tfile);
 
         return 0;
 }
@@ -1177,7 +1229,7 @@ static void tun_set_msglevel(struct net_device *dev, u32 value)
 static u32 tun_get_link(struct net_device *dev)
 {
         struct tun_struct *tun = netdev_priv(dev);
-        return tun->attached;
+        return !!tun->tfile;
 }
 
 static u32 tun_get_rx_csum(struct net_device *dev)