diff options
| -rw-r--r-- | include/linux/netdevice.h | 1 | ||||
| -rw-r--r-- | net/core/dev.c | 34 | ||||
| -rw-r--r-- | net/core/dev_ioctl.c | 19 | ||||
| -rw-r--r-- | net/core/sock.c | 17 |
4 files changed, 41 insertions, 30 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 60584b185a0..96e4c21e15e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1695,6 +1695,7 @@ extern int init_dummy_netdev(struct net_device *dev); extern struct net_device *dev_get_by_index(struct net *net, int ifindex); extern struct net_device *__dev_get_by_index(struct net *net, int ifindex); extern struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex); +extern int netdev_get_name(struct net *net, char *name, int ifindex); extern int dev_restart(struct net_device *dev); #ifdef CONFIG_NETPOLL_TRAP extern int netpoll_trap(void); diff --git a/net/core/dev.c b/net/core/dev.c index fc1e289397f..faebb398fb4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -792,6 +792,40 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex) EXPORT_SYMBOL(dev_get_by_index); /** + * netdev_get_name - get a netdevice name, knowing its ifindex. + * @net: network namespace + * @name: a pointer to the buffer where the name will be stored. + * @ifindex: the ifindex of the interface to get the name from. + * + * The use of raw_seqcount_begin() and cond_resched() before + * retrying is required as we want to give the writers a chance + * to complete when CONFIG_PREEMPT is not set. + */ +int netdev_get_name(struct net *net, char *name, int ifindex) +{ + struct net_device *dev; + unsigned int seq; + +retry: + seq = raw_seqcount_begin(&devnet_rename_seq); + rcu_read_lock(); + dev = dev_get_by_index_rcu(net, ifindex); + if (!dev) { + rcu_read_unlock(); + return -ENODEV; + } + + strcpy(name, dev->name); + rcu_read_unlock(); + if (read_seqcount_retry(&devnet_rename_seq, seq)) { + cond_resched(); + goto retry; + } + + return 0; +} + +/** * dev_getbyhwaddr_rcu - find a device by its hardware address * @net: the applicable net namespace * @type: media type of device diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c index 6cc0481faad..5b7d0e1d066 100644 --- a/net/core/dev_ioctl.c +++ b/net/core/dev_ioctl.c @@ -19,9 +19,8 @@ static int dev_ifname(struct net *net, struct ifreq __user *arg) { - struct net_device *dev; struct ifreq ifr; - unsigned seq; + int error; /* * Fetch the caller's info block. @@ -30,19 +29,9 @@ static int dev_ifname(struct net *net, struct ifreq __user *arg) if (copy_from_user(&ifr, arg, sizeof(struct ifreq))) return -EFAULT; -retry: - seq = read_seqcount_begin(&devnet_rename_seq); - rcu_read_lock(); - dev = dev_get_by_index_rcu(net, ifr.ifr_ifindex); - if (!dev) { - rcu_read_unlock(); - return -ENODEV; - } - - strcpy(ifr.ifr_name, dev->name); - rcu_read_unlock(); - if (read_seqcount_retry(&devnet_rename_seq, seq)) - goto retry; + error = netdev_get_name(net, ifr.ifr_name, ifr.ifr_ifindex); + if (error) + return error; if (copy_to_user(arg, &ifr, sizeof(struct ifreq))) return -EFAULT; diff --git a/net/core/sock.c b/net/core/sock.c index 88868a9d21d..d6d024cfaaa 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -571,9 +571,7 @@ static int sock_getbindtodevice(struct sock *sk, char __user *optval, int ret = -ENOPROTOOPT; #ifdef CONFIG_NETDEVICES struct net *net = sock_net(sk); - struct net_device *dev; char devname[IFNAMSIZ]; - unsigned seq; if (sk->sk_bound_dev_if == 0) { len = 0; @@ -584,20 +582,9 @@ static int sock_getbindtodevice(struct sock *sk, char __user *optval, if (len < IFNAMSIZ) goto out; -retry: - seq = read_seqcount_begin(&devnet_rename_seq); - rcu_read_lock(); - dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if); - ret = -ENODEV; - if (!dev) { - rcu_read_unlock(); + ret = netdev_get_name(net, devname, sk->sk_bound_dev_if); + if (ret) goto out; - } - - strcpy(devname, dev->name); - rcu_read_unlock(); - if (read_seqcount_retry(&devnet_rename_seq, seq)) - goto retry; len = strlen(devname) + 1; |