[PATCH v4 6/6] selftests/bpf: Add test cases for bpf_list_is_first/is_last/empty

[Chengkaitao <pilgrimtao@gmail.com>]

From: Kaitao Cheng <chengkaitao@kylinos.cn>

Rename test_list_add_del to list_add_del_and_check and extend it to
cover the new kfuncs: assert list non-empty after insert, assert
is_first(n) and is_last(m_1) after bpf_list_add, and assert list
empty after removing both nodes.

Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
---
 .../testing/selftests/bpf/bpf_experimental.h  | 15 +++++++++++
 .../selftests/bpf/progs/refcounted_kptr.c     | 27 +++++++++++++++----
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index fdcc7a054095..056b2de19b06 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -126,6 +126,21 @@ extern int bpf_list_add_impl(struct bpf_list_head *head, struct bpf_list_node *n
 /* Convenience macro to wrap over bpf_list_add_impl */
 #define bpf_list_add(head, new, prev) bpf_list_add_impl(head, new, prev, NULL, 0)
 
+/* Description
+ *	Return true if 'node' is the first node in the list with head 'head'.
+ */
+extern bool bpf_list_is_first(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
+
+/* Description
+ *	Return true if 'node' is the last node in the list with head 'head'.
+ */
+extern bool bpf_list_is_last(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
+
+/* Description
+ *	Return true if the list with head 'head' has no entries.
+ */
+extern bool bpf_list_empty(struct bpf_list_head *head) __ksym;
+
 /* Description
  *	Remove 'node' from rbtree with root 'root'
  * Returns
diff --git a/tools/testing/selftests/bpf/progs/refcounted_kptr.c b/tools/testing/selftests/bpf/progs/refcounted_kptr.c
index 5a83274e1d26..1b119fe16f5a 100644
--- a/tools/testing/selftests/bpf/progs/refcounted_kptr.c
+++ b/tools/testing/selftests/bpf/progs/refcounted_kptr.c
@@ -367,14 +367,14 @@ long insert_rbtree_and_stash__del_tree_##rem_tree(void *ctx)		\
 INSERT_STASH_READ(true, "insert_stash_read: remove from tree");
 INSERT_STASH_READ(false, "insert_stash_read: don't remove from tree");
 
-/* Insert one node in tree and list, remove it from tree, add a second
- * node after it in list with bpf_list_add, then remove both nodes from
- * list via bpf_list_del.
+/* Insert one node in tree and list, remove it from tree, add a second node
+ * after it with bpf_list_add, check bpf_list_is_first/is_last/empty, then
+ * remove both nodes from list via bpf_list_del.
  */
 SEC("tc")
-__description("test_list_add_del: test bpf_list_add/del")
+__description("list_add_del_and_check: test bpf_list_add/del/is_first/is_last/empty")
 __success __retval(0)
-long test_list_add_del(void *ctx)
+long list_add_del_and_check(void *ctx)
 {
 	long err = 0;
 	struct bpf_rb_node *rb;
@@ -386,6 +386,11 @@ long test_list_add_del(void *ctx)
 		return err;
 
 	bpf_spin_lock(&lock);
+	if (bpf_list_empty(&head)) {
+		bpf_spin_unlock(&lock);
+		return -7;
+	}
+
 	rb = bpf_rbtree_first(&root);
 	if (!rb) {
 		bpf_spin_unlock(&lock);
@@ -418,6 +423,14 @@ long test_list_add_del(void *ctx)
 		return -8;
 	}
 
+	if (!bpf_list_is_first(&head, &n->l) ||
+	    !bpf_list_is_last(&head, &m_1->l)) {
+		bpf_spin_unlock(&lock);
+		bpf_obj_drop(n);
+		bpf_obj_drop(m_1);
+		return -9;
+	}
+
 	l = bpf_list_del(&head, &n->l);
 	l_1 = bpf_list_del(&head, &m_1->l);
 	bpf_spin_unlock(&lock);
@@ -434,6 +447,10 @@ long test_list_add_del(void *ctx)
 	else
 		err = -6;
 
+	bpf_spin_lock(&lock);
+	if (!bpf_list_empty(&head))
+		err = -7;
+	bpf_spin_unlock(&lock);
 	return err;
 }
 
-- 
2.50.1 (Apple Git-155)