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-rw-r--r--lib/kunit/try-catch.c98
1 files changed, 98 insertions, 0 deletions
diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c
new file mode 100644
index 000000000..f7825991d
--- /dev/null
+++ b/lib/kunit/try-catch.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * An API to allow a function, that may fail, to be executed, and recover in a
+ * controlled manner.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+
+#include <kunit/test.h>
+#include <linux/completion.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+
+#include "try-catch-impl.h"
+
+void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)
+{
+ try_catch->try_result = -EFAULT;
+ kthread_complete_and_exit(try_catch->try_completion, -EFAULT);
+}
+EXPORT_SYMBOL_GPL(kunit_try_catch_throw);
+
+static int kunit_generic_run_threadfn_adapter(void *data)
+{
+ struct kunit_try_catch *try_catch = data;
+
+ try_catch->try(try_catch->context);
+
+ kthread_complete_and_exit(try_catch->try_completion, 0);
+}
+
+static unsigned long kunit_test_timeout(void)
+{
+ /*
+ * TODO(brendanhiggins@google.com): We should probably have some type of
+ * variable timeout here. The only question is what that timeout value
+ * should be.
+ *
+ * The intention has always been, at some point, to be able to label
+ * tests with some type of size bucket (unit/small, integration/medium,
+ * large/system/end-to-end, etc), where each size bucket would get a
+ * default timeout value kind of like what Bazel does:
+ * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
+ * There is still some debate to be had on exactly how we do this. (For
+ * one, we probably want to have some sort of test runner level
+ * timeout.)
+ *
+ * For more background on this topic, see:
+ * https://mike-bland.com/2011/11/01/small-medium-large.html
+ *
+ * If tests timeout due to exceeding sysctl_hung_task_timeout_secs,
+ * the task will be killed and an oops generated.
+ */
+ return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */
+}
+
+void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
+{
+ DECLARE_COMPLETION_ONSTACK(try_completion);
+ struct kunit *test = try_catch->test;
+ struct task_struct *task_struct;
+ int exit_code, time_remaining;
+
+ try_catch->context = context;
+ try_catch->try_completion = &try_completion;
+ try_catch->try_result = 0;
+ task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
+ try_catch,
+ "kunit_try_catch_thread");
+ if (IS_ERR(task_struct)) {
+ try_catch->catch(try_catch->context);
+ return;
+ }
+
+ time_remaining = wait_for_completion_timeout(&try_completion,
+ kunit_test_timeout());
+ if (time_remaining == 0) {
+ kunit_err(test, "try timed out\n");
+ try_catch->try_result = -ETIMEDOUT;
+ kthread_stop(task_struct);
+ }
+
+ exit_code = try_catch->try_result;
+
+ if (!exit_code)
+ return;
+
+ if (exit_code == -EFAULT)
+ try_catch->try_result = 0;
+ else if (exit_code == -EINTR)
+ kunit_err(test, "wake_up_process() was never called\n");
+ else if (exit_code)
+ kunit_err(test, "Unknown error: %d\n", exit_code);
+
+ try_catch->catch(try_catch->context);
+}
+EXPORT_SYMBOL_GPL(kunit_try_catch_run);