3 files changed, 21 insertions, 50 deletions

diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index 2f3af00643cf..4ca125e9b3ce 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -43,12 +43,8 @@ extern struct nf_conntrack_helper *
 __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple);
 
 extern struct nf_conntrack_helper *
-nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
-
-extern struct nf_conntrack_helper *
 __nf_conntrack_helper_find_byname(const char *name);
 
-extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
 extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
 
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 96aa637c0932..42f781fcba64 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -28,6 +28,7 @@
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_extend.h>
 
+static DEFINE_MUTEX(nf_ct_helper_mutex);
 static struct hlist_head *nf_ct_helper_hash __read_mostly;
 static unsigned int nf_ct_helper_hsize __read_mostly;
 static unsigned int nf_ct_helper_count __read_mostly;
@@ -54,42 +55,13 @@ __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
                 return NULL;
 
         h = helper_hash(tuple);
-        hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) {
+        hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) {
                 if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
                         return helper;
         }
         return NULL;
 }
-
-struct nf_conntrack_helper *
-nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple)
-{
-        struct nf_conntrack_helper *helper;
-
-        /* need nf_conntrack_lock to assure that helper exists until
-         * try_module_get() is called */
-        read_lock_bh(&nf_conntrack_lock);
-
-        helper = __nf_ct_helper_find(tuple);
-        if (helper) {
-                /* need to increase module usage count to assure helper will
-                 * not go away while the caller is e.g. busy putting a
-                 * conntrack in the hash that uses the helper */
-                if (!try_module_get(helper->me))
-                        helper = NULL;
-        }
-
-        read_unlock_bh(&nf_conntrack_lock);
-
-        return helper;
-}
-EXPORT_SYMBOL_GPL(nf_ct_helper_find_get);
-
-void nf_ct_helper_put(struct nf_conntrack_helper *helper)
-{
-        module_put(helper->me);
-}
-EXPORT_SYMBOL_GPL(nf_ct_helper_put);
+EXPORT_SYMBOL_GPL(__nf_ct_helper_find);
 
 struct nf_conntrack_helper *
 __nf_conntrack_helper_find_byname(const char *name)
@@ -99,7 +71,7 @@ __nf_conntrack_helper_find_byname(const char *name)
         unsigned int i;
 
         for (i = 0; i < nf_ct_helper_hsize; i++) {
-                hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) {
+                hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) {
                         if (!strcmp(h->name, name))
                                 return h;
                 }
@@ -140,10 +112,10 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
 
         BUG_ON(me->timeout == 0);
 
-        write_lock_bh(&nf_conntrack_lock);
-        hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]);
+        mutex_lock(&nf_ct_helper_mutex);
+        hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
         nf_ct_helper_count++;
-        write_unlock_bh(&nf_conntrack_lock);
+        mutex_unlock(&nf_ct_helper_mutex);
 
         return 0;
 }
@@ -156,10 +128,17 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
         struct hlist_node *n, *next;
         unsigned int i;
 
-        /* Need write lock here, to delete helper. */
-        write_lock_bh(&nf_conntrack_lock);
-        hlist_del(&me->hnode);
+        mutex_lock(&nf_ct_helper_mutex);
+        hlist_del_rcu(&me->hnode);
         nf_ct_helper_count--;
+        mutex_unlock(&nf_ct_helper_mutex);
+
+        /* Make sure every nothing is still using the helper unless its a
+         * connection in the hash.
+         */
+        synchronize_rcu();
+
+        write_lock_bh(&nf_conntrack_lock);
 
         /* Get rid of expectations */
         for (i = 0; i < nf_ct_expect_hsize; i++) {
@@ -182,9 +161,6 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
                         unhelp(h, me);
         }
         write_unlock_bh(&nf_conntrack_lock);
-
-        /* Someone could be still looking at the helper in a bh. */
-        synchronize_net();
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index bdae2924d425..b6c0935e09df 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1167,11 +1167,12 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
                 ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
 #endif
 
-        helper = nf_ct_helper_find_get(rtuple);
+        rcu_read_lock();
+        helper = __nf_ct_helper_find(rtuple);
         if (helper) {
                 help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
                 if (help == NULL) {
-                        nf_ct_helper_put(helper);
+                        rcu_read_unlock();
                         err = -ENOMEM;
                         goto err;
                 }
@@ -1187,9 +1188,7 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
 
         add_timer(&ct->timeout);
         nf_conntrack_hash_insert(ct);
-
-        if (helper)
-                nf_ct_helper_put(helper);
+        rcu_read_unlock();
 
         return 0;