[NETFILTER]: nf_queue: Use RCU and mutex for queue handlers
Queue handlers are registered/unregistered in only process context.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index f402894..823fbf4 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -17,7 +17,7 @@
*/
static struct nf_queue_handler *queue_handler[NPROTO];
-static DEFINE_RWLOCK(queue_handler_lock);
+static DEFINE_MUTEX(queue_handler_mutex);
/* return EBUSY when somebody else is registered, return EEXIST if the
* same handler is registered, return 0 in case of success. */
@@ -28,16 +28,16 @@
if (pf >= NPROTO)
return -EINVAL;
- write_lock_bh(&queue_handler_lock);
+ mutex_lock(&queue_handler_mutex);
if (queue_handler[pf] == qh)
ret = -EEXIST;
else if (queue_handler[pf])
ret = -EBUSY;
else {
- queue_handler[pf] = qh;
+ rcu_assign_pointer(queue_handler[pf], qh);
ret = 0;
}
- write_unlock_bh(&queue_handler_lock);
+ mutex_unlock(&queue_handler_mutex);
return ret;
}
@@ -49,14 +49,16 @@
if (pf >= NPROTO)
return -EINVAL;
- write_lock_bh(&queue_handler_lock);
+ mutex_lock(&queue_handler_mutex);
if (queue_handler[pf] != qh) {
- write_unlock_bh(&queue_handler_lock);
+ mutex_unlock(&queue_handler_mutex);
return -EINVAL;
}
- queue_handler[pf] = NULL;
- write_unlock_bh(&queue_handler_lock);
+ rcu_assign_pointer(queue_handler[pf], NULL);
+ mutex_unlock(&queue_handler_mutex);
+
+ synchronize_rcu();
return 0;
}
@@ -66,12 +68,14 @@
{
int pf;
- write_lock_bh(&queue_handler_lock);
+ mutex_lock(&queue_handler_mutex);
for (pf = 0; pf < NPROTO; pf++) {
if (queue_handler[pf] == qh)
- queue_handler[pf] = NULL;
+ rcu_assign_pointer(queue_handler[pf], NULL);
}
- write_unlock_bh(&queue_handler_lock);
+ mutex_unlock(&queue_handler_mutex);
+
+ synchronize_rcu();
}
EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
@@ -94,18 +98,21 @@
struct net_device *physoutdev = NULL;
#endif
struct nf_afinfo *afinfo;
+ struct nf_queue_handler *qh;
/* QUEUE == DROP if noone is waiting, to be safe. */
- read_lock(&queue_handler_lock);
- if (!queue_handler[pf]) {
- read_unlock(&queue_handler_lock);
+ rcu_read_lock();
+
+ qh = rcu_dereference(queue_handler[pf]);
+ if (!qh) {
+ rcu_read_unlock();
kfree_skb(skb);
return 1;
}
afinfo = nf_get_afinfo(pf);
if (!afinfo) {
- read_unlock(&queue_handler_lock);
+ rcu_read_unlock();
kfree_skb(skb);
return 1;
}
@@ -115,7 +122,7 @@
if (net_ratelimit())
printk(KERN_ERR "OOM queueing packet %p\n",
skb);
- read_unlock(&queue_handler_lock);
+ rcu_read_unlock();
kfree_skb(skb);
return 1;
}
@@ -125,7 +132,7 @@
/* If it's going away, ignore hook. */
if (!try_module_get(info->elem->owner)) {
- read_unlock(&queue_handler_lock);
+ rcu_read_unlock();
kfree(info);
return 0;
}
@@ -143,10 +150,9 @@
}
#endif
afinfo->saveroute(skb, info);
- status = queue_handler[pf]->outfn(skb, info, queuenum,
- queue_handler[pf]->data);
+ status = qh->outfn(skb, info, queuenum, qh->data);
- read_unlock(&queue_handler_lock);
+ rcu_read_unlock();
if (status < 0) {
/* James M doesn't say fuck enough. */
@@ -313,13 +319,13 @@
loff_t *pos = v;
struct nf_queue_handler *qh;
- read_lock_bh(&queue_handler_lock);
- qh = queue_handler[*pos];
+ rcu_read_lock();
+ qh = rcu_dereference(queue_handler[*pos]);
if (!qh)
ret = seq_printf(s, "%2lld NONE\n", *pos);
else
ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);
- read_unlock_bh(&queue_handler_lock);
+ rcu_read_unlock();
return ret;
}
