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Subject: Re: [PATCH v3 kunit-next 1/2] kunit: add debugfs
 /sys/kernel/debug/kunit/<suite>/results display
To:     Alan Maguire <alan.maguire@oracle.com>, brendanhiggins@google.com,
        gregkh@linuxfoundation.org, shuah@kernel.org
Cc:     linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        corbet@lwn.net, davidgow@google.com
References: <1581094694-6513-1-git-send-email-alan.maguire@oracle.com>
 <1581094694-6513-2-git-send-email-alan.maguire@oracle.com>
From:   Frank Rowand <frowand.list@gmail.com>
Message-ID: <c42ac237-476a-526f-b445-61e7a63bc101@gmail.com>
Date:   Wed, 12 Feb 2020 21:25:03 -0600
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On 2/7/20 10:58 AM, Alan Maguire wrote:
> add debugfs support for displaying kunit test suite results; this is
> especially useful for module-loaded tests to allow disentangling of
> test result display from other dmesg events.
> 
> As well as printk()ing messages, we append them to a per-test log.
> 
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
>  include/kunit/test.h   |  52 ++++++++++++++++---
>  lib/kunit/Makefile     |   3 +-
>  lib/kunit/debugfs.c    | 105 ++++++++++++++++++++++++++++++++++++++
>  lib/kunit/debugfs.h    |  16 ++++++
>  lib/kunit/kunit-test.c |   4 +-
>  lib/kunit/test.c       | 136 ++++++++++++++++++++++++++++++++++++++-----------
>  6 files changed, 274 insertions(+), 42 deletions(-)
>  create mode 100644 lib/kunit/debugfs.c
>  create mode 100644 lib/kunit/debugfs.h
> 
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index 2dfb550..6a73c4e 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -81,6 +81,9 @@ struct kunit_resource {
>  
>  struct kunit;
>  
> +/* Size of "lastrun" log associated with test. */
> +#define KUNIT_LOG_SIZE	512
> +
>  /**
>   * struct kunit_case - represents an individual test case.
>   *
> @@ -123,8 +126,14 @@ struct kunit_case {
>  
>  	/* private: internal use only. */
>  	bool success;
> +	char *log;
>  };
>  
> +static inline char *kunit_status_to_string(bool status)
> +{
> +	return status ? "ok" : "not ok";
> +}
> +
>  /**
>   * KUNIT_CASE - A helper for creating a &struct kunit_case
>   *
> @@ -157,6 +166,10 @@ struct kunit_suite {
>  	int (*init)(struct kunit *test);
>  	void (*exit)(struct kunit *test);
>  	struct kunit_case *test_cases;
> +
> +	/* private - internal use only */
> +	struct dentry *debugfs;
> +	char *log;
>  };
>  
>  /**
> @@ -175,6 +188,7 @@ struct kunit {
>  
>  	/* private: internal use only. */
>  	const char *name; /* Read only after initialization! */
> +	char *log; /* Points at case log after initialization */
>  	struct kunit_try_catch try_catch;
>  	/*
>  	 * success starts as true, and may only be set to false during a
> @@ -193,10 +207,19 @@ struct kunit {
>  	struct list_head resources; /* Protected by lock. */
>  };
>  
> -void kunit_init_test(struct kunit *test, const char *name);
> +void kunit_init_test(struct kunit *test, const char *name, char *log);
>  
>  int kunit_run_tests(struct kunit_suite *suite);
>  
> +size_t kunit_suite_num_test_cases(struct kunit_suite *suite);
> +
> +unsigned int kunit_test_case_num(struct kunit_suite *suite,
> +				 struct kunit_case *test_case);
> +
> +int __kunit_test_suites_init(struct kunit_suite **suites);
> +
> +void __kunit_test_suites_exit(struct kunit_suite **suites);
> +
>  /**
>   * kunit_test_suites() - used to register one or more &struct kunit_suite
>   *			 with KUnit.
> @@ -226,20 +249,24 @@ struct kunit {
>  	static struct kunit_suite *suites[] = { __VA_ARGS__, NULL};	\
>  	static int kunit_test_suites_init(void)				\
>  	{								\
> -		unsigned int i;						\
> -		for (i = 0; suites[i] != NULL; i++)			\
> -			kunit_run_tests(suites[i]);			\
> -		return 0;						\
> +		return __kunit_test_suites_init(suites);		\
>  	}								\
>  	late_initcall(kunit_test_suites_init);				\
>  	static void __exit kunit_test_suites_exit(void)			\
>  	{								\
> -		return;							\
> +		return __kunit_test_suites_exit(suites);		\
>  	}								\
>  	module_exit(kunit_test_suites_exit)
>  
>  #define kunit_test_suite(suite)	kunit_test_suites(&suite)
>  
> +#define kunit_suite_for_each_test_case(suite, test_case)		\
> +	for (test_case = suite->test_cases;				\
> +	     test_case && test_case->run_case;				\

test_case does not become NULL for the final entry in suite->test_cases
so do not test for such.


> +	     test_case++)
> +
> +bool kunit_suite_has_succeeded(struct kunit_suite *suite);
> +
>  /*
>   * Like kunit_alloc_resource() below, but returns the struct kunit_resource
>   * object that contains the allocation. This is mostly for testing purposes.
> @@ -356,8 +383,17 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
>  
>  void kunit_cleanup(struct kunit *test);
>  
> -#define kunit_printk(lvl, test, fmt, ...) \
> -	printk(lvl "\t# %s: " fmt, (test)->name, ##__VA_ARGS__)
> +/* printk and log to per-test or per-suite log buffer */
> +#define kunit_log(lvl, test, fmt, ...)				\

'test' can be either a test or a suite, so this name is misleading.  I suggest
changing it to test_or_suite.


> +	do {								\
> +		printk(lvl fmt, ##__VA_ARGS__);				\
> +		snprintf((test)->log, KUNIT_LOG_SIZE,			\
> +			  "%s" fmt "\n",				\
> +			 (test)->log, ##__VA_ARGS__);			\
> +	} while (0)
> +

If kunit_log() is called multiple times in a test run for a single test case,
does each call overwrite the previous value of (test)->log?  For example,
kunit_print_subtest_start() calls kunit_log() twice.


> +#define kunit_printk(lvl, test, fmt, ...)				\
> +	kunit_log(lvl, test, "\t# %s: " fmt, (test)->name, ##__VA_ARGS__)
>  
>  /**
>   * kunit_info() - Prints an INFO level message associated with @test.
> diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
> index fab5564..869aab0 100644
> --- a/lib/kunit/Makefile
> +++ b/lib/kunit/Makefile
> @@ -3,7 +3,8 @@ obj-$(CONFIG_KUNIT) +=			kunit.o
>  kunit-objs +=				test.o \
>  					string-stream.o \
>  					assert.o \
> -					try-catch.o
> +					try-catch.o \
> +					debugfs.o
>  
>  obj-$(CONFIG_KUNIT_TEST) +=		kunit-test.o
>  

Please make debugfs.o configurable distinctly from KUNIT.  Or it
might be possible to make KUNIT_LOG_SIZE zero (and make sure the
code handles a NULL log) if that is easier to implement.

The data size of the log buffers could otherwise be excessively
large for a tiny resource constrained embedded platform.  For
example, with the proposed KUNIT_LOG_SIZE of 512, if there were
200 test cases enabled, the log space would be 100k bytes.  If
2000 test cases were enabled, the log space would be 1000k bytes.

I can easily imagine a user configuring an acceptance test with
tens of thousands of test cases.


> diff --git a/lib/kunit/debugfs.c b/lib/kunit/debugfs.c
> new file mode 100644
> index 0000000..b856d6b
> --- /dev/null
> +++ b/lib/kunit/debugfs.c
> @@ -0,0 +1,105 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020, Oracle and/or its affiliates.
> + *    Author: Alan Maguire <alan.maguire@oracle.com>
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/module.h>
> +
> +#include <kunit/test.h>
> +
> +#include "string-stream.h"
> +
> +#define KUNIT_DEBUGFS_ROOT             "kunit"
> +#define KUNIT_DEBUGFS_RESULTS          "results"
> +
> +/*
> + * Create a debugfs representation of test suites:
> + *
> + * Path						Semantics
> + * /sys/kernel/debug/kunit/<testsuite>/results	Show results of last run for
> + *						testsuite
> + *
> + */
> +
> +static struct dentry *debugfs_rootdir;
> +
> +void kunit_debugfs_cleanup(void)
> +{
> +	debugfs_remove_recursive(debugfs_rootdir);
> +}
> +
> +void kunit_debugfs_init(void)
> +{
> +	if (!debugfs_rootdir)
> +		debugfs_rootdir = debugfs_create_dir(KUNIT_DEBUGFS_ROOT, NULL);
> +}
> +
> +static void debugfs_print_result(struct seq_file *seq,
> +				 struct kunit_suite *suite,
> +				 struct kunit_case *test_case)
> +{
> +	if (!test_case)
> +		return;
> +
> +	seq_printf(seq, "%s", test_case->log);
> +}
> +
> +/*
> + * /sys/kernel/debug/kunit/<testsuite>/results shows all results for testsuite.
> + */
> +static int debugfs_print_results(struct seq_file *seq, void *v)
> +{
> +	struct kunit_suite *suite = (struct kunit_suite *)seq->private;
> +	bool success = kunit_suite_has_succeeded(suite);
> +	struct kunit_case *test_case;
> +
> +	if (!suite)
> +		return 0;
> +
> +	seq_printf(seq, "%s", suite->log);
> +
> +	kunit_suite_for_each_test_case(suite, test_case)
> +		debugfs_print_result(seq, suite, test_case);
> +
> +	seq_printf(seq, "%s %d - %s\n",
> +		   kunit_status_to_string(success), 1, suite->name);
> +	return 0;
> +}
> +
> +static int debugfs_release(struct inode *inode, struct file *file)
> +{
> +	return single_release(inode, file);
> +}
> +
> +static int debugfs_results_open(struct inode *inode, struct file *file)
> +{
> +	struct kunit_suite *suite;
> +
> +	suite = (struct kunit_suite *)inode->i_private;
> +
> +	return single_open(file, debugfs_print_results, suite);
> +}
> +
> +static const struct file_operations debugfs_results_fops = {
> +	.open = debugfs_results_open,
> +	.read = seq_read,
> +	.llseek = seq_lseek,
> +	.release = debugfs_release,
> +};
> +
> +void kunit_debugfs_create_suite(struct kunit_suite *suite)
> +{
> +	/* First add /sys/kernel/debug/kunit/<testsuite> */
> +	suite->debugfs = debugfs_create_dir(suite->name, debugfs_rootdir);
> +
> +	debugfs_create_file(KUNIT_DEBUGFS_RESULTS, S_IFREG | 0444,
> +			    suite->debugfs,
> +			    suite, &debugfs_results_fops);
> +}
> +
> +void kunit_debugfs_destroy_suite(struct kunit_suite *suite)
> +{
> +	debugfs_remove_recursive(suite->debugfs);
> +}
> diff --git a/lib/kunit/debugfs.h b/lib/kunit/debugfs.h
> new file mode 100644
> index 0000000..9a92d5e
> --- /dev/null
> +++ b/lib/kunit/debugfs.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020, Oracle and/or its affiliates.
> + */
> +
> +#ifndef _KUNIT_DEBUGFS_H
> +#define _KUNIT_DEBUGFS_H
> +
> +#include <kunit/test.h>
> +
> +void kunit_debugfs_create_suite(struct kunit_suite *suite);
> +void kunit_debugfs_destroy_suite(struct kunit_suite *suite);
> +void kunit_debugfs_init(void);
> +void kunit_debugfs_cleanup(void);
> +
> +#endif /* _KUNIT_DEBUGFS_H */
> diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
> index ccb8d2e..aceb5bf 100644
> --- a/lib/kunit/kunit-test.c
> +++ b/lib/kunit/kunit-test.c
> @@ -134,7 +134,7 @@ static void kunit_resource_test_init_resources(struct kunit *test)
>  {
>  	struct kunit_test_resource_context *ctx = test->priv;
>  
> -	kunit_init_test(&ctx->test, "testing_test_init_test");
> +	kunit_init_test(&ctx->test, "testing_test_init_test", NULL);
>  
>  	KUNIT_EXPECT_TRUE(test, list_empty(&ctx->test.resources));
>  }
> @@ -301,7 +301,7 @@ static int kunit_resource_test_init(struct kunit *test)
>  
>  	test->priv = ctx;
>  
> -	kunit_init_test(&ctx->test, "test_test_context");
> +	kunit_init_test(&ctx->test, "test_test_context", NULL);
>  
>  	return 0;
>  }
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index 9242f93..aec607f 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -10,6 +10,7 @@
>  #include <linux/kernel.h>
>  #include <linux/sched/debug.h>
>  
> +#include "debugfs.h"
>  #include "string-stream.h"
>  #include "try-catch-impl.h"
>  
> @@ -28,73 +29,91 @@ static void kunit_print_tap_version(void)
>  	}
>  }
>  
> -static size_t kunit_test_cases_len(struct kunit_case *test_cases)
> +size_t kunit_suite_num_test_cases(struct kunit_suite *suite)
>  {
>  	struct kunit_case *test_case;
>  	size_t len = 0;
>  
> -	for (test_case = test_cases; test_case->run_case; test_case++)
> +	kunit_suite_for_each_test_case(suite, test_case)
>  		len++;
>  
>  	return len;
>  }
> +EXPORT_SYMBOL_GPL(kunit_suite_num_test_cases);
>  
>  static void kunit_print_subtest_start(struct kunit_suite *suite)
>  {
>  	kunit_print_tap_version();
> -	pr_info("\t# Subtest: %s\n", suite->name);
> -	pr_info("\t1..%zd\n", kunit_test_cases_len(suite->test_cases));
> +	kunit_log(KERN_INFO, suite, "# Subtest: %s", suite->name);
> +	kunit_log(KERN_INFO, suite, "1..%zd",
> +		  kunit_suite_num_test_cases(suite));

The subtest 'is a TAP stream indented 4 spaces'.  (So the old code was
also incorrect since it indented with a tab.)

kunit_print_ok_not_ok() has a similar indentation issue.


>  }
>  
> -static void kunit_print_ok_not_ok(bool should_indent,
> +static void kunit_print_ok_not_ok(void *test_or_suite,
> +				  bool is_test,
>  				  bool is_ok,
>  				  size_t test_number,
>  				  const char *description)
>  {
> -	const char *indent, *ok_not_ok;
> +	struct kunit_suite *suite = is_test ? NULL : test_or_suite;
> +	struct kunit *test = is_test ? test_or_suite : NULL;
>  
> -	if (should_indent)
> -		indent = "\t";
> -	else
> -		indent = "";
> -
> -	if (is_ok)
> -		ok_not_ok = "ok";
> +	/*
> +	 * We do not log the test suite results as doing so would
> +	 * mean debugfs display would consist of the test suite
> +	 * description and status prior to individual test results.
> +	 * Hence directly printk the suite status, and we will
> +	 * separately seq_printf() the suite status for the debugfs
> +	 * representation.
> +	 */
> +	if (suite)
> +		pr_info("%s %zd - %s",
> +			kunit_status_to_string(is_ok),
> +			test_number, description);
>  	else
> -		ok_not_ok = "not ok";
> -
> -	pr_info("%s%s %zd - %s\n", indent, ok_not_ok, test_number, description);
> +		kunit_log(KERN_INFO, test, "\t%s %zd - %s",
> +			  kunit_status_to_string(is_ok),
> +			  test_number, description);
>  }
>  
> -static bool kunit_suite_has_succeeded(struct kunit_suite *suite)
> +bool kunit_suite_has_succeeded(struct kunit_suite *suite)
>  {
>  	const struct kunit_case *test_case;
>  
> -	for (test_case = suite->test_cases; test_case->run_case; test_case++)
> +	kunit_suite_for_each_test_case(suite, test_case) {
>  		if (!test_case->success)
>  			return false;
> +	}
>  
>  	return true;
>  }
> +EXPORT_SYMBOL_GPL(kunit_suite_has_succeeded);
>  
>  static void kunit_print_subtest_end(struct kunit_suite *suite)
>  {
>  	static size_t kunit_suite_counter = 1;
>  
> -	kunit_print_ok_not_ok(false,
> +	kunit_print_ok_not_ok((void *)suite, false,
>  			      kunit_suite_has_succeeded(suite),
>  			      kunit_suite_counter++,
>  			      suite->name);
>  }
>  
> -static void kunit_print_test_case_ok_not_ok(struct kunit_case *test_case,
> -					    size_t test_number)
> +unsigned int kunit_test_case_num(struct kunit_suite *suite,
> +				 struct kunit_case *test_case)
>  {
> -	kunit_print_ok_not_ok(true,
> -			      test_case->success,
> -			      test_number,
> -			      test_case->name);
> +	struct kunit_case *tc;
> +	unsigned int i = 1;
> +
> +	kunit_suite_for_each_test_case(suite, tc) {
> +		if (tc == test_case)
> +			return i;
> +		i++;
> +	}
> +
> +	return 0;
>  }
> +EXPORT_SYMBOL_GPL(kunit_test_case_num);
>  
>  static void kunit_print_string_stream(struct kunit *test,
>  				      struct string_stream *stream)
> @@ -102,6 +121,9 @@ static void kunit_print_string_stream(struct kunit *test,
>  	struct string_stream_fragment *fragment;
>  	char *buf;
>  
> +	if (string_stream_is_empty(stream))
> +		return;
> +
>  	buf = string_stream_get_string(stream);
>  	if (!buf) {
>  		kunit_err(test,
> @@ -175,11 +197,14 @@ void kunit_do_assertion(struct kunit *test,
>  }
>  EXPORT_SYMBOL_GPL(kunit_do_assertion);
>  
> -void kunit_init_test(struct kunit *test, const char *name)
> +void kunit_init_test(struct kunit *test, const char *name, char *log)
>  {
>  	spin_lock_init(&test->lock);
>  	INIT_LIST_HEAD(&test->resources);
>  	test->name = name;
> +	test->log = log;
> +	if (test->log)
> +		test->log[0] = '\0';
>  	test->success = true;
>  }
>  EXPORT_SYMBOL_GPL(kunit_init_test);
> @@ -290,7 +315,7 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
>  	struct kunit_try_catch *try_catch;
>  	struct kunit test;
>  
> -	kunit_init_test(&test, test_case->name);
> +	kunit_init_test(&test, test_case->name, test_case->log);
>  	try_catch = &test.try_catch;
>  
>  	kunit_try_catch_init(try_catch,
> @@ -303,19 +328,20 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
>  	kunit_try_catch_run(try_catch, &context);
>  
>  	test_case->success = test.success;
> +
> +	kunit_print_ok_not_ok(&test, true, test_case->success,
> +			      kunit_test_case_num(suite, test_case),
> +			      test_case->name);
>  }
>  
>  int kunit_run_tests(struct kunit_suite *suite)
>  {
>  	struct kunit_case *test_case;
> -	size_t test_case_count = 1;
>  
>  	kunit_print_subtest_start(suite);
>  
> -	for (test_case = suite->test_cases; test_case->run_case; test_case++) {
> +	kunit_suite_for_each_test_case(suite, test_case)
>  		kunit_run_case_catch_errors(suite, test_case);
> -		kunit_print_test_case_ok_not_ok(test_case, test_case_count++);
> -	}
>  
>  	kunit_print_subtest_end(suite);
>  
> @@ -323,6 +349,51 @@ int kunit_run_tests(struct kunit_suite *suite)
>  }
>  EXPORT_SYMBOL_GPL(kunit_run_tests);
>  
> +static void kunit_init_suite(struct kunit_suite *suite)
> +{
> +	struct kunit_case *test_case;
> +
> +	/* Allocate logs before creating debugfs representation. */
> +	suite->log = kzalloc(KUNIT_LOG_SIZE, GFP_KERNEL);
> +	kunit_suite_for_each_test_case(suite, test_case)
> +		test_case->log = kzalloc(KUNIT_LOG_SIZE, GFP_KERNEL);
> +
> +	kunit_debugfs_create_suite(suite);
> +}
> +
> +int __kunit_test_suites_init(struct kunit_suite **suites)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; suites[i] != NULL; i++) {
> +		kunit_init_suite(suites[i]);
> +		kunit_run_tests(suites[i]);
> +	}
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(__kunit_test_suites_init);
> +
> +static void kunit_exit_suite(struct kunit_suite *suite)
> +{
> +	struct kunit_case *test_case;
> +
> +	/* Destroy debugfs representation before freeing logs used by it. */
> +	kunit_debugfs_destroy_suite(suite);
> +
> +	kfree(suite->log);
> +	kunit_suite_for_each_test_case(suite, test_case)
> +		kfree(test_case->log);
> +}
> +
> +void __kunit_test_suites_exit(struct kunit_suite **suites)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; suites[i] != NULL; i++)
> +		kunit_exit_suite(suites[i]);
> +}
> +EXPORT_SYMBOL_GPL(__kunit_test_suites_exit);
> +
>  struct kunit_resource *kunit_alloc_and_get_resource(struct kunit *test,
>  						    kunit_resource_init_t init,
>  						    kunit_resource_free_t free,
> @@ -489,12 +560,15 @@ void kunit_cleanup(struct kunit *test)
>  
>  static int __init kunit_init(void)
>  {
> +	kunit_debugfs_init();
> +
>  	return 0;
>  }
>  late_initcall(kunit_init);
>  
>  static void __exit kunit_exit(void)
>  {
> +	kunit_debugfs_cleanup();
>  }
>  module_exit(kunit_exit);
>  
>