ipv6: addrconf: factorize inet6_addr_hash() call

ipv6_add_addr_hash() can compute the hash value outside of
locked section and pass it to ipv6_chk_same_addr().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 10 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9228030e3497..c1a5028f394c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -956,9 +956,8 @@ static u32 inet6_addr_hash(const struct in6_addr *addr)
 }
 
 static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
-                               struct net_device *dev)
+                               struct net_device *dev, unsigned int hash)
 {
-        unsigned int hash = inet6_addr_hash(addr);
         struct inet6_ifaddr *ifp;
 
         hlist_for_each_entry(ifp, &inet6_addr_lst[hash], addr_lst) {
@@ -974,23 +973,19 @@ static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
 
 static int ipv6_add_addr_hash(struct net_device *dev, struct inet6_ifaddr *ifa)
 {
-        unsigned int hash;
+        unsigned int hash = inet6_addr_hash(&ifa->addr);
         int err = 0;
 
         spin_lock(&addrconf_hash_lock);
 
         /* Ignore adding duplicate addresses on an interface */
-        if (ipv6_chk_same_addr(dev_net(dev), &ifa->addr, dev)) {
+        if (ipv6_chk_same_addr(dev_net(dev), &ifa->addr, dev, hash)) {
                 ADBG("ipv6_add_addr: already assigned\n");
                 err = -EEXIST;
-                goto out;
+        } else {
+                hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
         }
 
-        /* Add to big hash table */
-        hash = inet6_addr_hash(&ifa->addr);
-        hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
-
-out:
         spin_unlock(&addrconf_hash_lock);
 
         return err;