ipv6: refactor __ipv6_dev_ac_inc()

Refactor out allocation and initialization and make
the refcount code more readable.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 66c1932..952c1fd 100644 (file)
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -203,6 +203,11 @@ void ipv6_sock_ac_close(struct sock *sk)
        rtnl_unlock();
 }
 
+static void aca_get(struct ifacaddr6 *aca)
+{
+       atomic_inc(&aca->aca_refcnt);
+}
+
 static void aca_put(struct ifacaddr6 *ac)
 {
        if (atomic_dec_and_test(&ac->aca_refcnt)) {
@@ -212,6 +217,29 @@ static void aca_put(struct ifacaddr6 *ac)
        }
 }
 
+static struct ifacaddr6 *aca_alloc(struct rt6_info *rt,
+                                  const struct in6_addr *addr)
+{
+       struct inet6_dev *idev = rt->rt6i_idev;
+       struct ifacaddr6 *aca;
+
+       aca = kzalloc(sizeof(*aca), GFP_ATOMIC);
+       if (aca == NULL)
+               return NULL;
+
+       aca->aca_addr = *addr;
+       in6_dev_hold(idev);
+       aca->aca_idev = idev;
+       aca->aca_rt = rt;
+       aca->aca_users = 1;
+       /* aca_tstamp should be updated upon changes */
+       aca->aca_cstamp = aca->aca_tstamp = jiffies;
+       atomic_set(&aca->aca_refcnt, 1);
+       spin_lock_init(&aca->aca_lock);
+
+       return aca;
+}
+
 /*
  *     device anycast group inc (add if not found)
  */
@@ -223,7 +251,6 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
 
        ASSERT_RTNL();
 
-       in6_dev_hold(idev);
        write_lock_bh(&idev->lock);
        if (idev->dead) {
                err = -ENODEV;
@@ -238,35 +265,25 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
                }
        }
 
-       /*
-        *      not found: create a new one.
-        */
-
-       aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
-
-       if (aca == NULL) {
-               err = -ENOMEM;
-               goto out;
-       }
-
        rt = addrconf_dst_alloc(idev, addr, true);
        if (IS_ERR(rt)) {
-               kfree(aca);
                err = PTR_ERR(rt);
                goto out;
        }
-
-       aca->aca_addr = *addr;
-       aca->aca_idev = idev;
-       aca->aca_rt = rt;
-       aca->aca_users = 1;
-       /* aca_tstamp should be updated upon changes */
-       aca->aca_cstamp = aca->aca_tstamp = jiffies;
-       atomic_set(&aca->aca_refcnt, 2);
-       spin_lock_init(&aca->aca_lock);
+       aca = aca_alloc(rt, addr);
+       if (aca == NULL) {
+               ip6_rt_put(rt);
+               err = -ENOMEM;
+               goto out;
+       }
 
        aca->aca_next = idev->ac_list;
        idev->ac_list = aca;
+
+       /* Hold this for addrconf_join_solict() below before we unlock,
+        * it is already exposed via idev->ac_list.
+        */
+       aca_get(aca);
        write_unlock_bh(&idev->lock);
 
        ip6_ins_rt(rt);
@@ -277,7 +294,6 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
        return 0;
 out:
        write_unlock_bh(&idev->lock);
-       in6_dev_put(idev);
        return err;
 }