net: device name allocation cleanups

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 45 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index c128af708ebf..9977288583b8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -893,7 +893,8 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
                 free_page((unsigned long) inuse);
         }
 
-        snprintf(buf, IFNAMSIZ, name, i);
+        if (buf != name)
+                snprintf(buf, IFNAMSIZ, name, i);
         if (!__dev_get_by_name(net, buf))
                 return i;
 
@@ -933,6 +934,21 @@ int dev_alloc_name(struct net_device *dev, const char *name)
 }
 EXPORT_SYMBOL(dev_alloc_name);
 
+static int dev_get_valid_name(struct net *net, const char *name, char *buf,
+                              bool fmt)
+{
+        if (!dev_valid_name(name))
+                return -EINVAL;
+
+        if (fmt && strchr(name, '%'))
+                return __dev_alloc_name(net, name, buf);
+        else if (__dev_get_by_name(net, name))
+                return -EEXIST;
+        else if (buf != name)
+                strlcpy(buf, name, IFNAMSIZ);
+
+        return 0;
+}
 
 /**
  *      dev_change_name - change name of a device
@@ -956,22 +972,14 @@ int dev_change_name(struct net_device *dev, const char *newname)
         if (dev->flags & IFF_UP)
                 return -EBUSY;
 
-        if (!dev_valid_name(newname))
-                return -EINVAL;
-
         if (strncmp(newname, dev->name, IFNAMSIZ) == 0)
                 return 0;
 
         memcpy(oldname, dev->name, IFNAMSIZ);
 
-        if (strchr(newname, '%')) {
-                err = dev_alloc_name(dev, newname);
-                if (err < 0)
-                        return err;
-        } else if (__dev_get_by_name(net, newname))
-                return -EEXIST;
-        else
-                strlcpy(dev->name, newname, IFNAMSIZ);
+        err = dev_get_valid_name(net, newname, dev->name, 1);
+        if (err < 0)
+                return err;
 
 rollback:
         /* For now only devices in the initial network namespace
@@ -4883,8 +4891,6 @@ EXPORT_SYMBOL(netdev_fix_features);
 
 int register_netdevice(struct net_device *dev)
 {
-        struct hlist_head *head;
-        struct hlist_node *p;
         int ret;
         struct net *net = dev_net(dev);
 
@@ -4913,26 +4919,14 @@ int register_netdevice(struct net_device *dev)
                 }
         }
 
-        if (!dev_valid_name(dev->name)) {
-                ret = -EINVAL;
+        ret = dev_get_valid_name(net, dev->name, dev->name, 0);
+        if (ret)
                 goto err_uninit;
-        }
 
         dev->ifindex = dev_new_index(net);
         if (dev->iflink == -1)
                 dev->iflink = dev->ifindex;
 
-        /* Check for existence of name */
-        head = dev_name_hash(net, dev->name);
-        hlist_for_each(p, head) {
-                struct net_device *d
-                        = hlist_entry(p, struct net_device, name_hlist);
-                if (!strncmp(d->name, dev->name, IFNAMSIZ)) {
-                        ret = -EEXIST;
-                        goto err_uninit;
-                }
-        }
-
         /* Fix illegal checksum combinations */
         if ((dev->features & NETIF_F_HW_CSUM) &&
             (dev->features & (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
@@ -5460,8 +5454,6 @@ EXPORT_SYMBOL(unregister_netdev);
 
 int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat)
 {
-        char buf[IFNAMSIZ];
-        const char *destname;
         int err;
 
         ASSERT_RTNL();
@@ -5494,20 +5486,11 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
          * we can use it in the destination network namespace.
          */
         err = -EEXIST;
-        destname = dev->name;
-        if (__dev_get_by_name(net, destname)) {
+        if (__dev_get_by_name(net, dev->name)) {
                 /* We get here if we can't use the current device name */
                 if (!pat)
                         goto out;
-                if (!dev_valid_name(pat))
-                        goto out;
-                if (strchr(pat, '%')) {
-                        if (__dev_alloc_name(net, pat, buf) < 0)
-                                goto out;
-                        destname = buf;
-                } else
-                        destname = pat;
-                if (__dev_get_by_name(net, destname))
+                if (dev_get_valid_name(net, pat, dev->name, 1))
                         goto out;
         }
 
@@ -5544,10 +5527,6 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
         /* Actually switch the network namespace */
         dev_net_set(dev, net);
 
-        /* Assign the new device name */
-        if (destname != dev->name)
-                strcpy(dev->name, destname);
-
         /* If there is an ifindex conflict assign a new one */
         if (__dev_get_by_index(net, dev->ifindex)) {
                 int iflink = (dev->iflink == dev->ifindex);