docs: cgroup-v2: fix misc.events key format descriptiongrafted

In misc cgroup, misc.events does not output a simple "max" key. Instead,
each registered misc resource outputs a separate key suffixed with ".max"
(i.e., "<res>.max").
Update the documentation to clarify that the entry key is "<res>.max".

Suggested-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/include/kunit/skbuff.h b/include/kunit/skbuff.h
new file mode 100644
index 000000000..077846943
--- /dev/null
+++ b/include/kunit/skbuff.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit resource management helpers for SKBs (skbuff).
+ *
+ * Copyright (C) 2023 Intel Corporation
+ */
+
+#ifndef _KUNIT_SKBUFF_H
+#define _KUNIT_SKBUFF_H
+
+#include <kunit/resource.h>
+#include <linux/skbuff.h>
+
+static void kunit_action_kfree_skb(void *p)
+{
+	kfree_skb((struct sk_buff *)p);
+}
+
+/**
+ * kunit_zalloc_skb() - Allocate and initialize a resource managed skb.
+ * @test: The test case to which the skb belongs
+ * @len: size to allocate
+ * @gfp: allocation flags
+ *
+ * Allocate a new struct sk_buff with gfp flags, zero fill the given length
+ * and add it as a resource to the kunit test for automatic cleanup.
+ *
+ * Returns: newly allocated SKB, or %NULL on error
+ */
+static inline struct sk_buff *kunit_zalloc_skb(struct kunit *test, int len,
+					       gfp_t gfp)
+{
+	struct sk_buff *res = alloc_skb(len, gfp);
+
+	if (!res || skb_pad(res, len))
+		return NULL;
+
+	if (kunit_add_action_or_reset(test, kunit_action_kfree_skb, res))
+		return NULL;
+
+	return res;
+}
+
+/**
+ * kunit_kfree_skb() - Like kfree_skb except for allocations managed by KUnit.
+ * @test: The test case to which the resource belongs.
+ * @skb: The SKB to free.
+ */
+static inline void kunit_kfree_skb(struct kunit *test, struct sk_buff *skb)
+{
+	if (!skb)
+		return;
+
+	kunit_release_action(test, kunit_action_kfree_skb, (void *)skb);
+}
+
+#endif /* _KUNIT_SKBUFF_H */