dmatest: add a 'wait' parameter

Allows for scripting test runs by module load / unload.  Prevent module
load from returning until 'iterations' (finite) tests have completed, or
cause reads of the 'wait' parameter in sysfs to pause until the tests
are done.

Also killed the local waitqueue since we can just let the thread exit
naturally as long as we hold a reference.

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 47 insertions, 25 deletions

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index 26b50206963..dd4d84d556d 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -161,6 +161,43 @@ struct dmatest_chan {
 	struct list_head	threads;
 };
 
+static DECLARE_WAIT_QUEUE_HEAD(thread_wait);
+static bool wait;
+
+static bool is_threaded_test_run(struct dmatest_info *info)
+{
+	struct dmatest_chan *dtc;
+
+	list_for_each_entry(dtc, &info->channels, node) {
+		struct dmatest_thread *thread;
+
+		list_for_each_entry(thread, &dtc->threads, node) {
+			if (!thread->done)
+				return true;
+		}
+	}
+
+	return false;
+}
+
+static int dmatest_wait_get(char *val, const struct kernel_param *kp)
+{
+	struct dmatest_info *info = &test_info;
+	struct dmatest_params *params = &info->params;
+
+	if (params->iterations)
+		wait_event(thread_wait, !is_threaded_test_run(info));
+	wait = true;
+	return param_get_bool(val, kp);
+}
+
+static struct kernel_param_ops wait_ops = {
+	.get = dmatest_wait_get,
+	.set = param_set_bool,
+};
+module_param_cb(wait, &wait_ops, &wait, S_IRUGO);
+MODULE_PARM_DESC(wait, "Wait for tests to complete (default: false)");
+
 static bool dmatest_match_channel(struct dmatest_params *params,
 		struct dma_chan *chan)
 {
@@ -660,12 +697,7 @@ err_thread_type:
 		dmaengine_terminate_all(chan);
 
 	thread->done = true;
-
-	if (params->iterations > 0)
-		while (!kthread_should_stop()) {
-			DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_dmatest_exit);
-			interruptible_sleep_on(&wait_dmatest_exit);
-		}
+	wake_up(&thread_wait);
 
 	return ret;
 }
@@ -681,6 +713,7 @@ static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
 		pr_debug("thread %s exited with status %d\n",
 			 thread->task->comm, ret);
 		list_del(&thread->node);
+		put_task_struct(thread->task);
 		kfree(thread);
 	}
 
@@ -719,18 +752,19 @@ static int dmatest_add_threads(struct dmatest_info *info,
 		thread->chan = dtc->chan;
 		thread->type = type;
 		smp_wmb();
-		thread->task = kthread_run(dmatest_func, thread, "%s-%s%u",
+		thread->task = kthread_create(dmatest_func, thread, "%s-%s%u",
 				dma_chan_name(chan), op, i);
 		if (IS_ERR(thread->task)) {
-			pr_warn("Failed to run thread %s-%s%u\n",
+			pr_warn("Failed to create thread %s-%s%u\n",
 				dma_chan_name(chan), op, i);
 			kfree(thread);
 			break;
 		}
 
 		/* srcbuf and dstbuf are allocated by the thread itself */
-
+		get_task_struct(thread->task);
 		list_add_tail(&thread->node, &dtc->threads);
+		wake_up_process(thread->task);
 	}
 
 	return i;
@@ -863,22 +897,6 @@ static void restart_threaded_test(struct dmatest_info *info, bool run)
 	run_threaded_test(info);
 }
 
-static bool is_threaded_test_run(struct dmatest_info *info)
-{
-	struct dmatest_chan *dtc;
-
-	list_for_each_entry(dtc, &info->channels, node) {
-		struct dmatest_thread *thread;
-
-		list_for_each_entry(thread, &dtc->threads, node) {
-			if (!thread->done)
-				return true;
-		}
-	}
-
-	return false;
-}
-
 static int dmatest_run_get(char *val, const struct kernel_param *kp)
 {
 	struct dmatest_info *info = &test_info;
@@ -920,6 +938,7 @@ static int dmatest_run_set(const char *val, const struct kernel_param *kp)
 static int __init dmatest_init(void)
 {
 	struct dmatest_info *info = &test_info;
+	struct dmatest_params *params = &info->params;
 
 	if (dmatest_run) {
 		mutex_lock(&info->lock);
@@ -927,6 +946,9 @@ static int __init dmatest_init(void)
 		mutex_unlock(&info->lock);
 	}
 
+	if (params->iterations && wait)
+		wait_event(thread_wait, !is_threaded_test_run(info));
+
 	/* module parameters are stable, inittime tests are started,
 	 * let userspace take over 'run' control
 	 */