dmatest: cancel thread immediately when asked for

If user have the timeout alike issues and wants to cancel the thread
immediately, the current call of wait_event_freezable_timeout is preventing to
this until timeout is expired. Thus, user will experience the unnecessary
delays.

Adding kthread_should_stop() check inside wait_event_freezable_timeout() solves
that.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dmatest.c

@@ -454,7 +454,8 @@ static int dmatest_func(void *data)
 		}
 		dma_async_issue_pending(chan);
 
-		wait_event_freezable_timeout(done_wait, done.done,
+		wait_event_freezable_timeout(done_wait,
+					     done.done || kthread_should_stop(),
 					     msecs_to_jiffies(timeout));
 
 		status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);