list_is_head() was added recently[1], and didn't have a KUnit test. The implementation is trivial, so it's not a particularly exciting test, but it'd be nice to get back to full coverage of the list functions.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/in...

Signed-off-by: David Gow davidgow@google.com Acked-by: Daniel Latypov dlatypov@google.com Acked-by: Brendan Higgins brendanhiggins@google.com ---

Changes since v2: https://lore.kernel.org/linux-kselftest/20220208040122.695258-2-davidgow@goo... - Use the _MSG variants of the assert macros, as suggested by Daniel Latypov. Changes since v1: https://lore.kernel.org/linux-kselftest/20220205061539.273330-2-davidgow@goo... - Test both non-head elements of the same list and head elements of different lists.

--- lib/list-test.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)

diff --git a/lib/list-test.c b/lib/list-test.c index f82a3c7788b8..19f13059439b 100644 --- a/lib/list-test.c +++ b/lib/list-test.c @@ -253,6 +253,24 @@ static void list_test_list_bulk_move_tail(struct kunit *test) KUNIT_EXPECT_EQ(test, i, 2); }

+static void list_test_list_is_head(struct kunit *test) +{ + struct list_head a, b, c; + + /* Two lists: [a] -> b, [c] */ + INIT_LIST_HEAD(&a); + INIT_LIST_HEAD(&c); + list_add_tail(&b, &a); + + KUNIT_EXPECT_TRUE_MSG(test, list_is_head(&a, &a), + "Head element of same list"); + KUNIT_EXPECT_FALSE_MSG(test, list_is_head(&a, &b), + "Non-head element of same list"); + KUNIT_EXPECT_FALSE_MSG(test, list_is_head(&a, &c), + "Head element of different list"); +} + + static void list_test_list_is_first(struct kunit *test) { struct list_head a, b; @@ -730,6 +748,7 @@ static struct kunit_case list_test_cases[] = { KUNIT_CASE(list_test_list_move), KUNIT_CASE(list_test_list_move_tail), KUNIT_CASE(list_test_list_bulk_move_tail), + KUNIT_CASE(list_test_list_is_head), KUNIT_CASE(list_test_list_is_first), KUNIT_CASE(list_test_list_is_last), KUNIT_CASE(list_test_list_empty),

On Wed, Feb 09, 2022 at 01:28:11PM +0800, David Gow wrote:

The list_del_init_careful() function was added[1] after the list KUnit test. Add a very basic test to cover it.

Note that this test only covers the single-threaded behaviour (which matches list_del_init()), as is already the case with the test for list_empty_careful().

Now the negative tests make more sense, thanks!

Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com to the entire series.

Signed-off-by: David Gow davidgow@google.com

Changes since v2: https://lore.kernel.org/linux-kselftest/20220208040122.695258-1-davidgow@goo...

• Fix the test calling list_del_init() instead of list_del_init_careful()
• Improve the comment noting we only test single-threaded behaviour.

Changes since v1: https://lore.kernel.org/linux-kselftest/20220205061539.273330-1-davidgow@goo...

• Patch 1/3 unchanged

---

lib/list-test.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)

diff --git a/lib/list-test.c b/lib/list-test.c index ee09505df16f..f82a3c7788b8 100644 --- a/lib/list-test.c +++ b/lib/list-test.c @@ -161,6 +161,25 @@ static void list_test_list_del_init(struct kunit *test) KUNIT_EXPECT_TRUE(test, list_empty_careful(&a)); } +static void list_test_list_del_init_careful(struct kunit *test) +{

• /* NOTE: This test only checks the behaviour of this function in

• * isolation. It does not verify memory model guarantees. */
  

• struct list_head a, b;
• LIST_HEAD(list);
• list_add_tail(&a, &list);
• list_add_tail(&b, &list);
• /* before: [list] -> a -> b */
• list_del_init_careful(&a);
• /* after: [list] -> b, a initialised */
• KUNIT_EXPECT_PTR_EQ(test, list.next, &b);
• KUNIT_EXPECT_PTR_EQ(test, b.prev, &list);
• KUNIT_EXPECT_TRUE(test, list_empty_careful(&a));

+}

static void list_test_list_move(struct kunit *test) { struct list_head a, b; @@ -707,6 +726,7 @@ static struct kunit_case list_test_cases[] = { KUNIT_CASE(list_test_list_replace_init), KUNIT_CASE(list_test_list_swap), KUNIT_CASE(list_test_list_del_init),

• KUNIT_CASE(list_test_list_del_init_careful), KUNIT_CASE(list_test_list_move), KUNIT_CASE(list_test_list_move_tail), KUNIT_CASE(list_test_list_bulk_move_tail),

-- 2.35.0.263.gb82422642f-goog