netfilter: nf_conncount: Move locking into count_tree()
This patch is originally from Florian Westphal.
This is a preparation patch to allow lockless traversal
of the tree via RCU.
Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index 7dfd9d5..d1a4fd1 100644
--- a/net/netfilter/nf_conncount.c
+++ b/net/netfilter/nf_conncount.c
@@ -262,18 +262,26 @@ static void tree_nodes_free(struct rb_root *root,
}
static unsigned int
-count_tree(struct net *net, struct rb_root *root,
- const u32 *key, u8 keylen,
+count_tree(struct net *net,
+ struct nf_conncount_data *data,
+ const u32 *key,
const struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone)
{
struct nf_conncount_rb *gc_nodes[CONNCOUNT_GC_MAX_NODES];
+ struct rb_root *root;
struct rb_node **rbnode, *parent;
struct nf_conncount_rb *rbconn;
struct nf_conncount_tuple *conn;
- unsigned int gc_count;
+ unsigned int gc_count, hash;
bool no_gc = false;
+ unsigned int count = 0;
+ u8 keylen = data->keylen;
+ hash = jhash2(key, data->keylen, conncount_rnd) % CONNCOUNT_SLOTS;
+ root = &data->root[hash];
+
+ spin_lock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
restart:
gc_count = 0;
parent = NULL;
@@ -292,20 +300,20 @@ count_tree(struct net *net, struct rb_root *root,
rbnode = &((*rbnode)->rb_right);
} else {
/* same source network -> be counted! */
- unsigned int count;
-
nf_conncount_lookup(net, &rbconn->list, tuple, zone,
&addit);
count = rbconn->list.count;
tree_nodes_free(root, gc_nodes, gc_count);
if (!addit)
- return count;
+ goto out_unlock;
if (!nf_conncount_add(&rbconn->list, tuple, zone))
- return 0; /* hotdrop */
+ count = 0; /* hotdrop */
+ goto out_unlock;
- return count + 1;
+ count++;
+ goto out_unlock;
}
if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes))
@@ -328,18 +336,18 @@ count_tree(struct net *net, struct rb_root *root,
goto restart;
}
+ count = 0;
if (!tuple)
- return 0;
-
+ goto out_unlock;
/* no match, need to insert new node */
rbconn = kmem_cache_alloc(conncount_rb_cachep, GFP_ATOMIC);
if (rbconn == NULL)
- return 0;
+ goto out_unlock;
conn = kmem_cache_alloc(conncount_conn_cachep, GFP_ATOMIC);
if (conn == NULL) {
kmem_cache_free(conncount_rb_cachep, rbconn);
- return 0;
+ goto out_unlock;
}
conn->tuple = *tuple;
@@ -348,10 +356,13 @@ count_tree(struct net *net, struct rb_root *root,
nf_conncount_list_init(&rbconn->list);
list_add(&conn->node, &rbconn->list.head);
+ count = 1;
rb_link_node(&rbconn->node, parent, rbnode);
rb_insert_color(&rbconn->node, root);
- return 1;
+out_unlock:
+ spin_unlock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
+ return count;
}
/* Count and return number of conntrack entries in 'net' with particular 'key'.
@@ -363,20 +374,7 @@ unsigned int nf_conncount_count(struct net *net,
const struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone)
{
- struct rb_root *root;
- int count;
- u32 hash;
-
- hash = jhash2(key, data->keylen, conncount_rnd) % CONNCOUNT_SLOTS;
- root = &data->root[hash];
-
- spin_lock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
-
- count = count_tree(net, root, key, data->keylen, tuple, zone);
-
- spin_unlock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
-
- return count;
+ return count_tree(net, data, key, tuple, zone);
}
EXPORT_SYMBOL_GPL(nf_conncount_count);
