Bluetooth: hci_core: fix list_for_each_entry_rcu usage

Releasing + re-acquiring RCU lock inside list_for_each_entry_rcu() loop
body is not correct.

Fix by taking the update-side hdev->lock instead.

Fixes: c7eaf80 ("Bluetooth: Fix hci_link_tx_to RCU lock usage")
Signed-off-by: Pauli Virtanen <[email protected]>
Reviewed-by: Paul Menzel <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: pv

net/bluetooth/hci_core.c

@@ -3417,23 +3417,18 @@ static void hci_link_tx_to(struct hci_dev *hdev, __u8 type)
 
 	bt_dev_err(hdev, "link tx timeout");
 
-	rcu_read_lock();
+	hci_dev_lock(hdev);
 
 	/* Kill stalled connections */
-	list_for_each_entry_rcu(c, &h->list, list) {
+	list_for_each_entry(c, &h->list, list) {
 		if (c->type == type && c->sent) {
 			bt_dev_err(hdev, "killing stalled connection %pMR",
 				   &c->dst);
-			/* hci_disconnect might sleep, so, we have to release
-			 * the RCU read lock before calling it.
-			 */
-			rcu_read_unlock();
 			hci_disconnect(c, HCI_ERROR_REMOTE_USER_TERM);
-			rcu_read_lock();
 		}
 	}
 
-	rcu_read_unlock();
+	hci_dev_unlock(hdev);
 }
 
 static struct hci_chan *hci_chan_sent(struct hci_dev *hdev, __u8 type,