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>

1 files changed, 39 insertions, 23 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 66c19320119a..952c1fd06150 100644
--- 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;
 }