ipvs: add ip_vs_dest_hold and ip_vs_dest_put

ip_vs_dest_hold will be used under RCU lock
while ip_vs_dest_put can be called even after dest
is removed from service, as it happens for conns and
some schedulers.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

3 files changed, 6 insertions, 11 deletions

diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index e3e2b4d3b6d8..1b29e4a2b26c 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -554,7 +554,7 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
                 return;
 
         /* Increase the refcnt counter of the dest */
-        atomic_inc(&dest->refcnt);
+        ip_vs_dest_hold(dest);
 
         conn_flags = atomic_read(&dest->conn_flags);
         if (cp->protocol != IPPROTO_UDP)
@@ -700,12 +700,7 @@ static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
         }
 
-        /*
-         * Simply decrease the refcnt of the dest, because the
-         * dest will be either in service's destination list
-         * or in the trash.
-         */
-        atomic_dec(&dest->refcnt);
+        ip_vs_dest_put(dest);
 }
 
 static int expire_quiescent_template(struct netns_ipvs *ipvs,
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index d64f800a3426..a4f638880470 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -616,7 +616,7 @@ struct ip_vs_dest *ip_vs_find_dest(struct net  *net, int af,
         if (!dest)
                 dest = ip_vs_lookup_dest(svc, daddr, port ^ dport);
         if (dest)
-                atomic_inc(&dest->refcnt);
+                ip_vs_dest_hold(dest);
         ip_vs_service_put(svc);
         return dest;
 }
@@ -1056,7 +1056,7 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest)
                               ntohs(dest->port),
                               atomic_read(&dest->refcnt));
                 list_add(&dest->n_list, &ipvs->dest_trash);
-                atomic_inc(&dest->refcnt);
+                ip_vs_dest_hold(dest);
         }
 }
 
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 44fd10c539ac..6cc3e52f1f35 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -861,7 +861,7 @@ static void ip_vs_proc_conn(struct net *net, struct ip_vs_conn_param *param,
                 if (!dest) {
                         dest = ip_vs_try_bind_dest(cp);
                         if (dest)
-                                atomic_dec(&dest->refcnt);
+                                ip_vs_dest_put(dest);
                 }
         } else {
                 /*
@@ -874,7 +874,7 @@ static void ip_vs_proc_conn(struct net *net, struct ip_vs_conn_param *param,
 
                 cp = ip_vs_conn_new(param, daddr, dport, flags, dest, fwmark);
                 if (dest)
-                        atomic_dec(&dest->refcnt);
+                        ip_vs_dest_put(dest);
                 if (!cp) {
                         if (param->pe_data)
                                 kfree(param->pe_data);