Merge branches 'x86/urgent', 'x86/amd-iommu', 'x86/apic', 'x86/cleanups', 'x86/core...

[linux-2.6-omap-h63xx.git] / net / netfilter / nf_conntrack_helper.c

diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 96aa637c09327e6c79a85ec6a76cd86228aa908a..8e0b4c8f62a8da1156d72c5e96b8c6f9e1c42e29 100644 (file)
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -20,6 +20,7 @@
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/rculist.h>
 
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_l3proto.h>
@@ -28,6 +29,7 @@
 #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 +56,13 @@ __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 +72,7 @@ __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;
                }
@@ -138,12 +111,13 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
 {
        unsigned int h = helper_hash(&me->tuple);
 
-       BUG_ON(me->timeout == 0);
+       BUG_ON(me->expect_policy == NULL);
+       BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES);
 
-       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;
 }
@@ -153,13 +127,20 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
 {
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_expect *exp;
-       struct hlist_node *n, *next;
+       const 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();
+
+       spin_lock_bh(&nf_conntrack_lock);
 
        /* Get rid of expectations */
        for (i = 0; i < nf_ct_expect_hsize; i++) {
@@ -181,10 +162,7 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
                hlist_for_each_entry(h, n, &nf_conntrack_hash[i], hnode)
                        unhelp(h, me);
        }
-       write_unlock_bh(&nf_conntrack_lock);
-
-       /* Someone could be still looking at the helper in a bh. */
-       synchronize_net();
+       spin_unlock_bh(&nf_conntrack_lock);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);