Bluetooth: Use RCU to manipulate chan_list
Instead of using tasklet_disable() to prevent acess to the channel use, we
can use RCU and improve the performance of our code.
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index e6d8a22..b044676 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -960,9 +960,7 @@
chan->conn = conn;
skb_queue_head_init(&chan->data_q);
- tasklet_disable(&hdev->tx_task);
- list_add(&conn->chan_list, &chan->list);
- tasklet_enable(&hdev->tx_task);
+ list_add_rcu(&chan->list, &conn->chan_list);
return chan;
}
@@ -974,9 +972,9 @@
BT_DBG("%s conn %p chan %p", hdev->name, conn, chan);
- tasklet_disable(&hdev->tx_task);
- list_del(&chan->list);
- tasklet_enable(&hdev->tx_task);
+ list_del_rcu(&chan->list);
+
+ synchronize_rcu();
skb_queue_purge(&chan->data_q);
kfree(chan);
@@ -986,10 +984,10 @@
void hci_chan_list_flush(struct hci_conn *conn)
{
- struct hci_chan *chan, *tmp;
+ struct hci_chan *chan;
BT_DBG("conn %p", conn);
- list_for_each_entry_safe(chan, tmp, &conn->chan_list, list)
+ list_for_each_entry_rcu(chan, &conn->chan_list, list)
hci_chan_del(chan);
}
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 36763aa..2c4f32f 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2135,7 +2135,9 @@
conn_num++;
- list_for_each_entry(tmp, &conn->chan_list, list) {
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(tmp, &conn->chan_list, list) {
struct sk_buff *skb;
if (skb_queue_empty(&tmp->data_q))
@@ -2159,6 +2161,8 @@
}
}
+ rcu_read_unlock();
+
if (hci_conn_num(hdev, type) == conn_num)
break;
}
@@ -2207,7 +2211,9 @@
num++;
- list_for_each_entry(chan, &conn->chan_list, list) {
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(chan, &conn->chan_list, list) {
struct sk_buff *skb;
if (chan->sent) {
@@ -2228,6 +2234,8 @@
skb->priority);
}
+ rcu_read_unlock();
+
if (hci_conn_num(hdev, type) == num)
break;
}