inet: RCU changes in inetdev_by_index()

Convert inetdev_by_index() to not increment in_dev refcount.

Callers hold RCU or RTNL, and should not decrement in_dev refcount.

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

1 files changed, 11 insertions, 14 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 0f80dfc2f7fb..6734c9cab248 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -590,32 +590,29 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
                 if (!dev)
                         goto out;
                 dev_hold(dev);
-                err = -ENETDOWN;
-                if (!(dev->flags & IFF_UP))
-                        goto out;
-                err = 0;
-out:
-                rcu_read_unlock();
-                return err;
+                err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
         } else {
                 struct in_device *in_dev;
 
                 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
                         return -EINVAL;
 
+                rcu_read_lock();
+                err = -ENODEV;
                 in_dev = inetdev_by_index(net, nh->nh_oif);
                 if (in_dev == NULL)
-                        return -ENODEV;
-                if (!(in_dev->dev->flags & IFF_UP)) {
-                        in_dev_put(in_dev);
-                        return -ENETDOWN;
-                }
+                        goto out;
+                err = -ENETDOWN;
+                if (!(in_dev->dev->flags & IFF_UP))
+                        goto out;
                 nh->nh_dev = in_dev->dev;
                 dev_hold(nh->nh_dev);
                 nh->nh_scope = RT_SCOPE_HOST;
-                in_dev_put(in_dev);
+                err = 0;
         }
-        return 0;
+out:
+        rcu_read_unlock();
+        return err;
 }
 
 static inline unsigned int fib_laddr_hashfn(__be32 val)