1 files changed, 34 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index fc1e289397f5..faebb398fb46 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