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 ---

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 | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)

diff --git a/lib/list-test.c b/lib/list-test.c index 976e9ae1f3c5..1960615d1a9f 100644 --- a/lib/list-test.c +++ b/lib/list-test.c @@ -252,6 +252,23 @@ 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(test, list_is_head(&a, &a)); + /* Non-head element of same list */ + KUNIT_EXPECT_FALSE(test, list_is_head(&a, &b)); + /* Head element of different list */ + KUNIT_EXPECT_FALSE(test, list_is_head(&a, &c)); +} + + static void list_test_list_is_first(struct kunit *test) { struct list_head a, b; @@ -729,6 +746,7 @@ 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 Mon, Feb 7, 2022 at 8:01 PM David Gow davidgow@google.com 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().

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

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

• Patch 1/3 unchanged

---

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

diff --git a/lib/list-test.c b/lib/list-test.c index ee09505df16f..976e9ae1f3c5 100644 --- a/lib/list-test.c +++ b/lib/list-test.c @@ -161,6 +161,24 @@ 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) +{

•   /* This test doesn't check correctness under concurrent access */
  

nit: I personally didn't read this comment in the intended way at first. I'd personally find something like

NOTE: this doesn't test for concurrency/memory ordering/however-you-want-to-word-it issues

a bit more readable.

•   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(&a);
  

Is this supposed to use list_del_init_careful(&a)? That would make it match the name of the test case.

•   /* 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 +725,7 @@ 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