[PATCH] Fix linked-list KUnit test when run multiple times

[PATCH] Fix linked-list KUnit test when run multiple times

[David Gow]

A few of the lists used in the linked-list KUnit tests (the
for_each_entry{,_reverse} tests) are declared 'static', and so are
not-reinitialised if the test runs multiple times. This was not a
problem when KUnit tests were run once on startup, but when tests are
able to be run manually (e.g. from debugfs[1]), this is no longer the
case.

Making these lists no longer 'static' causes the lists to be
reinitialised, and the test passes each time it is run. While there may
be some value in testing that initialising static lists works, the
for_each_entry_* tests are unlikely to be the right place for it.

Signed-off-by: David Gow <davidgow@google.com>
---
 lib/list-test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/list-test.c b/lib/list-test.c
index 76babb1df889..ee09505df16f 100644
--- a/lib/list-test.c
+++ b/lib/list-test.c
@@ -659,7 +659,7 @@ static void list_test_list_for_each_prev_safe(struct kunit *test)
 static void list_test_list_for_each_entry(struct kunit *test)
 {
 	struct list_test_struct entries[5], *cur;
-	static LIST_HEAD(list);
+	LIST_HEAD(list);
 	int i = 0;
 
 	for (i = 0; i < 5; ++i) {
@@ -680,7 +680,7 @@ static void list_test_list_for_each_entry(struct kunit *test)
 static void list_test_list_for_each_entry_reverse(struct kunit *test)
 {
 	struct list_test_struct entries[5], *cur;
-	static LIST_HEAD(list);
+	LIST_HEAD(list);
 	int i = 0;
 
 	for (i = 0; i < 5; ++i) {
-- 
2.25.0.341.g760bfbb309-goog

Re: [PATCH] Fix linked-list KUnit test when run multiple times

[Brendan Higgins]

On Fri, Jan 24, 2020 at 11:46 AM David Gow <davidgow@google.com> wrote:
>
> A few of the lists used in the linked-list KUnit tests (the
> for_each_entry{,_reverse} tests) are declared 'static', and so are
> not-reinitialised if the test runs multiple times. This was not a
> problem when KUnit tests were run once on startup, but when tests are
> able to be run manually (e.g. from debugfs[1]), this is no longer the
> case.
>
> Making these lists no longer 'static' causes the lists to be
> reinitialised, and the test passes each time it is run. While there may
> be some value in testing that initialising static lists works, the
> for_each_entry_* tests are unlikely to be the right place for it.

Oh good, I am glad we are getting rid of those static variables. (I
thought we already dropped those - whoops.) I think this drops this
last of them, can you confirm David?

Regardless, this patch looks good to me.

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

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>

Thanks for taking care of this!

Re: [PATCH] Fix linked-list KUnit test when run multiple times

[David Gow]

On Fri, Jan 24, 2020 at 2:01 PM Brendan Higgins
<brendanhiggins@google.com> wrote:
> Oh good, I am glad we are getting rid of those static variables. (I
> thought we already dropped those - whoops.) I think this drops this
> last of them, can you confirm David?

Yeah, this is the last of them.

I vaguely recall a suggestion that it may be worth testing that the
LIST_HEAD() macro works with static, but as mentioned in the
description, the for_each_entry_* tests probably aren't the best place
to do that anyway...

-- David

Re: [PATCH] Fix linked-list KUnit test when run multiple times

[Brendan Higgins]

On Fri, Jan 24, 2020 at 3:13 PM David Gow <davidgow@google.com> wrote:
>
> On Fri, Jan 24, 2020 at 2:01 PM Brendan Higgins
> <brendanhiggins@google.com> wrote:
> > Oh good, I am glad we are getting rid of those static variables. (I
> > thought we already dropped those - whoops.) I think this drops this
> > last of them, can you confirm David?
>
> Yeah, this is the last of them.
>
> I vaguely recall a suggestion that it may be worth testing that the
> LIST_HEAD() macro works with static, but as mentioned in the
> description, the for_each_entry_* tests probably aren't the best place
> to do that anyway...

Ah, I think I missed that. Makes sense.