Re: [PATCH] lib/atomic64_test.c: convert to use KUnit

[David Gow]

On Tue, May 3, 2022 at 3:23 AM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
>
> The test currently is a bunch of checks (implemented using BUG_ON())
> that can be built into the kernel or as a module.
>
> Convert it to a KUnit test, which can also run in both modes.
> From a user's perspective, this change adds a CONFIG_KUNIT=y dep and
> changes the output format of the test [1]. The test itself is the same.
>
> This hopefully makes the test easier to run and more consistent with
> similar tests in lib/.
> Since it has no dependencies, it can be run without explicitly setting
> up a .kunitconfig via
> $ ./tools/testing/kunit/kunit.py run atomic
> ...
> [13:53:44] Starting KUnit Kernel (1/1)...
> [13:53:44] ============================================================
> [13:53:47] =================== atomic (2 subtests) ====================
> [13:53:47] [PASSED] test_atomic
> [13:53:47] [PASSED] test_atomic64
> [13:53:47] ===================== [PASSED] atomic ======================
> [13:53:47] ============================================================
> [13:53:47] Testing complete. Passed: 2, Failed: 0, Crashed: 0, Skipped: 0, Errors: 0
> [13:53:47] Elapsed time: 13.902s total, 1.629s configuring, 9.331s building, 2.852s running
>
> It can be run on ARCH=x86_64 (and others) via:
> $ ./tools/testing/kunit/kunit.py run --arch=x86_64 atomic
>
> The message about which platform the test ran on won't show up in
> kunit.py, but still gets printed out in dmesg, e.g.
> > TAP version 14
> > 1..1
> >     # Subtest: atomic
> >     1..2
> >     ok 1 - test_atomic
> >     ok 2 - test_atomic64
> >     # atomic: ran on x86-64 platform with CX8 and with SSE
> > # atomic: pass:2 fail:0 skip:0 total:2
> > # Totals: pass:2 fail:0 skip:0 total:2
> > ok 1 - atomic
>
> Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
>
> [1] https://www.kernel.org/doc/html/latest/dev-tools/ktap.html
> ---

This looks good to me. It's nice to see these tests being standardised.

> Meta:
> 1. this patch applies on top of the kunit branch,
> https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/?h=kunit

(To anyone else trying it: make sure you update this first, as the
prerequisites only just landed.)

> 2. checkpatch complains about aligning with parens, but it wants me to
> indent the `#ifdef CONFIG_X86_64` which seems inappropriate in context.

Huh... checkpatch isn't showing any such warning on my system.

> 3. this file doesn't seem to have a clear maintainer, so I assume this
> conversion is fine to go through the kunit branch. The only observable
> differences are the new CONFIG_KUNIT=y dep and more standardized (KTAP)
> output format.
> ---

I'm happy to vouch for this not breaking anything, even though I'm
definitely not an expert on the atomics code.

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

-- David

>  lib/Kconfig.debug   |   4 +-
>  lib/atomic64_test.c | 107 +++++++++++++++++++++-----------------------
>  2 files changed, 55 insertions(+), 56 deletions(-)
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 075cd25363ac..4cf8d5feda0a 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -2223,7 +2223,9 @@ config PERCPU_TEST
>           If unsure, say N.
>
>  config ATOMIC64_SELFTEST
> -       tristate "Perform an atomic64_t self-test"
> +       tristate "Perform an atomic64_t self-test" if !KUNIT_ALL_TESTS
> +       depends on KUNIT
> +       default KUNIT_ALL_TESTS
>         help
>           Enable this option to test the atomic64_t functions at boot or
>           at module load time.
> diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
> index d9d170238165..46cb0130f8d0 100644
> --- a/lib/atomic64_test.c
> +++ b/lib/atomic64_test.c
> @@ -5,13 +5,9 @@
>   * Copyright © 2010  Luca Barbieri
>   */
>
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +#include <kunit/test.h>
>
> -#include <linux/init.h>
> -#include <linux/bug.h>
> -#include <linux/kernel.h>
>  #include <linux/atomic.h>
> -#include <linux/module.h>
>
>  #ifdef CONFIG_X86
>  #include <asm/cpufeature.h>    /* for boot_cpu_has below */
> @@ -23,9 +19,7 @@ do {                                                          \
>         r = v0;                                                 \
>         atomic##bit##_##op(val, &v);                            \
>         r c_op val;                                             \
> -       WARN(atomic##bit##_read(&v) != r, "%Lx != %Lx\n",       \
> -               (unsigned long long)atomic##bit##_read(&v),     \
> -               (unsigned long long)r);                         \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_read(&v), r);       \
>  } while (0)
>
>  /*
> @@ -46,8 +40,8 @@ do {                                                          \
>         atomic##bit##_set(&v, v0);                              \
>         r = v0;                                                 \
>         r c_op val;                                             \
> -       BUG_ON(atomic##bit##_##op(val, &v) != r);               \
> -       BUG_ON(atomic##bit##_read(&v) != r);                    \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_##op(val, &v), r);  \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_read(&v), r);       \
>  } while (0)
>
>  #define TEST_FETCH(bit, op, c_op, val)                         \
> @@ -55,8 +49,8 @@ do {                                                          \
>         atomic##bit##_set(&v, v0);                              \
>         r = v0;                                                 \
>         r c_op val;                                             \
> -       BUG_ON(atomic##bit##_##op(val, &v) != v0);              \
> -       BUG_ON(atomic##bit##_read(&v) != r);                    \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_##op(val, &v), v0); \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_read(&v), r);       \
>  } while (0)
>
>  #define RETURN_FAMILY_TEST(bit, op, c_op, val)                 \
> @@ -72,8 +66,8 @@ do {                                                          \
>  #define TEST_ARGS(bit, op, init, ret, expect, args...)         \
>  do {                                                           \
>         atomic##bit##_set(&v, init);                            \
> -       BUG_ON(atomic##bit##_##op(&v, ##args) != ret);          \
> -       BUG_ON(atomic##bit##_read(&v) != expect);               \
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_##op(&v, ##args), ret);\
> +       KUNIT_ASSERT_EQ(test, atomic##bit##_read(&v), expect);  \
>  } while (0)
>
>  #define XCHG_FAMILY_TEST(bit, init, new)                               \
> @@ -101,7 +95,7 @@ do {                                                 \
>                         i, (i) - one, (i) - one);       \
>  } while (0)
>
> -static __init void test_atomic(void)
> +static void test_atomic(struct kunit *test)
>  {
>         int v0 = 0xaaa31337;
>         int v1 = 0xdeadbeef;
> @@ -144,7 +138,7 @@ static __init void test_atomic(void)
>  }
>
>  #define INIT(c) do { atomic64_set(&v, c); r = c; } while (0)
> -static __init void test_atomic64(void)
> +static void test_atomic64(struct kunit *test)
>  {
>         long long v0 = 0xaaa31337c001d00dLL;
>         long long v1 = 0xdeadbeefdeafcafeLL;
> @@ -156,12 +150,12 @@ static __init void test_atomic64(void)
>
>         atomic64_t v = ATOMIC64_INIT(v0);
>         long long r = v0;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         atomic64_set(&v, v1);
>         r = v1;
> -       BUG_ON(v.counter != r);
> -       BUG_ON(atomic64_read(&v) != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
> +       KUNIT_ASSERT_EQ(test, atomic64_read(&v), r);
>
>         TEST(64, add, +=, onestwos);
>         TEST(64, add, +=, -one);
> @@ -190,12 +184,12 @@ static __init void test_atomic64(void)
>         INIT(v0);
>         atomic64_inc(&v);
>         r += one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(v0);
>         atomic64_dec(&v);
>         r -= one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INC_RETURN_FAMILY_TEST(64, v0);
>         DEC_RETURN_FAMILY_TEST(64, v0);
> @@ -204,73 +198,76 @@ static __init void test_atomic64(void)
>         CMPXCHG_FAMILY_TEST(64, v0, v1, v2);
>
>         INIT(v0);
> -       BUG_ON(atomic64_add_unless(&v, one, v0));
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_FALSE(test, atomic64_add_unless(&v, one, v0));
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(v0);
> -       BUG_ON(!atomic64_add_unless(&v, one, v1));
> +       KUNIT_ASSERT_TRUE(test, atomic64_add_unless(&v, one, v1));
>         r += one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(onestwos);
> -       BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
> +       KUNIT_ASSERT_EQ(test, atomic64_dec_if_positive(&v), (onestwos - 1));
>         r -= one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(0);
> -       BUG_ON(atomic64_dec_if_positive(&v) != -one);
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, atomic64_dec_if_positive(&v), -one);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(-one);
> -       BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, atomic64_dec_if_positive(&v), (-one - one));
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(onestwos);
> -       BUG_ON(!atomic64_inc_not_zero(&v));
> +       KUNIT_ASSERT_TRUE(test, atomic64_inc_not_zero(&v));
>         r += one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(0);
> -       BUG_ON(atomic64_inc_not_zero(&v));
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_FALSE(test, atomic64_inc_not_zero(&v));
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         INIT(-one);
> -       BUG_ON(!atomic64_inc_not_zero(&v));
> +       KUNIT_ASSERT_TRUE(test, atomic64_inc_not_zero(&v));
>         r += one;
> -       BUG_ON(v.counter != r);
> +       KUNIT_ASSERT_EQ(test, v.counter, r);
>
>         /* Confirm the return value fits in an int, even if the value doesn't */
>         INIT(v3);
> +
>         r_int = atomic64_inc_not_zero(&v);
> -       BUG_ON(!r_int);
> +       KUNIT_ASSERT_NE(test, r_int, 0);
>  }
>
> -static __init int test_atomics_init(void)
> -{
> -       test_atomic();
> -       test_atomic64();
> +static struct kunit_case atomic_test_cases[] = {
> +       KUNIT_CASE(test_atomic),
> +       KUNIT_CASE(test_atomic64),
> +       {},
> +};
>
> +static void atomic_suite_exit(struct kunit_suite *suite)
> +{
>  #ifdef CONFIG_X86
> -       pr_info("passed for %s platform %s CX8 and %s SSE\n",
> +       kunit_info(suite, "ran on %s platform %s CX8 and %s SSE\n",
>  #ifdef CONFIG_X86_64
> -               "x86-64",
> +                  "x86-64",
>  #elif defined(CONFIG_X86_CMPXCHG64)
> -               "i586+",
> +                  "i586+",
>  #else
> -               "i386+",
> +                  "i386+",
>  #endif
> -              boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
> -              boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
> -#else
> -       pr_info("passed\n");
> +                  boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
> +                  boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
>  #endif
> -
> -       return 0;
>  }
>
> -static __exit void test_atomics_exit(void) {}
> +static struct kunit_suite atomic_test_suite = {
> +       .name = "atomic",
> +       .test_cases = atomic_test_cases,
> +       .suite_exit = atomic_suite_exit,
> +};
>
> -module_init(test_atomics_init);
> -module_exit(test_atomics_exit);
> +kunit_test_suites(&atomic_test_suite);
>
>  MODULE_LICENSE("GPL");
>
> base-commit: 38289a26e1b8a37755f3e07056ca416c1ee2a2e8
> --
> 2.36.0.464.gb9c8b46e94-goog
>