rtnetlink: rtnl_setlink() and rtnl_getlink() changes

rtnl_getlink() & rtnl_setlink() run with RTNL held, we can use
__dev_get_by_index() and __dev_get_by_name() variants and avoid
dev_hold()/dev_put()

Adds to rtnl_getlink() the capability to find a device by its name,
not only by its index.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 19 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index eb42873f2a3a..ba13b0974a7b 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -910,9 +910,9 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         err = -EINVAL;
         ifm = nlmsg_data(nlh);
         if (ifm->ifi_index > 0)
-                dev = dev_get_by_index(net, ifm->ifi_index);
+                dev = __dev_get_by_index(net, ifm->ifi_index);
         else if (tb[IFLA_IFNAME])
-                dev = dev_get_by_name(net, ifname);
+                dev = __dev_get_by_name(net, ifname);
         else
                 goto errout;
 
@@ -922,11 +922,9 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         }
 
         if ((err = validate_linkmsg(dev, tb)) < 0)
-                goto errout_dev;
+                goto errout;
 
         err = do_setlink(dev, ifm, tb, ifname, 0);
-errout_dev:
-        dev_put(dev);
 errout:
         return err;
 }
@@ -1154,6 +1152,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 {
         struct net *net = sock_net(skb->sk);
         struct ifinfomsg *ifm;
+        char ifname[IFNAMSIZ];
         struct nlattr *tb[IFLA_MAX+1];
         struct net_device *dev = NULL;
         struct sk_buff *nskb;
@@ -1163,19 +1162,23 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
         if (err < 0)
                 return err;
 
+        if (tb[IFLA_IFNAME])
+                nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
+
         ifm = nlmsg_data(nlh);
-        if (ifm->ifi_index > 0) {
-                dev = dev_get_by_index(net, ifm->ifi_index);
-                if (dev == NULL)
-                        return -ENODEV;
-        } else
+        if (ifm->ifi_index > 0)
+                dev = __dev_get_by_index(net, ifm->ifi_index);
+        else if (tb[IFLA_IFNAME])
+                dev = __dev_get_by_name(net, ifname);
+        else
                 return -EINVAL;
 
+        if (dev == NULL)
+                return -ENODEV;
+
         nskb = nlmsg_new(if_nlmsg_size(dev), GFP_KERNEL);
-        if (nskb == NULL) {
-                err = -ENOBUFS;
-                goto errout;
-        }
+        if (nskb == NULL)
+                return -ENOBUFS;
 
         err = rtnl_fill_ifinfo(nskb, dev, RTM_NEWLINK, NETLINK_CB(skb).pid,
                                nlh->nlmsg_seq, 0, 0);
@@ -1183,11 +1186,8 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                 /* -EMSGSIZE implies BUG in if_nlmsg_size */
                 WARN_ON(err == -EMSGSIZE);
                 kfree_skb(nskb);
-                goto errout;
-        }
-        err = rtnl_unicast(nskb, net, NETLINK_CB(skb).pid);
-errout:
-        dev_put(dev);
+        } else
+                err = rtnl_unicast(nskb, net, NETLINK_CB(skb).pid);
 
         return err;
 }