Bluetooth: cmtp: Fix deadlock in session deletion

Commit fada4ac339 introduced the usage of kthread API.
kthread_stop is a blocking function which returns only when
the thread exits. In this case, the thread can't exit because it's
waiting for the write lock, which is being held by cmtp_del_connection()
which is waiting for the thread to exit -- deadlock.

Revert cmtp_reset_ctr to its original behavior: non-blocking signalling
for the session to terminate.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c
index 2eb854a..42cb2f4 100644
--- a/net/bluetooth/cmtp/core.c
+++ b/net/bluetooth/cmtp/core.c
@@ -295,7 +295,7 @@
 	while (1) {
 		set_current_state(TASK_INTERRUPTIBLE);
 
-		if (kthread_should_stop())
+		if (atomic_read(&session->terminate))
 			break;
 		if (sk->sk_state != BT_CONNECTED)
 			break;
@@ -416,7 +416,8 @@
 		skb_queue_purge(&session->transmit);
 
 		/* Stop session thread */
-		kthread_stop(session->task);
+		atomic_inc(&session->terminate);
+		wake_up_process(session->task);
 	} else
 		err = -ENOENT;