[PATCH 14/20] headers: add list_count_nodes() backport for kernels < 6.5

[Yi Cong <cong.yi@linux.dev>]

From: Yi Cong <yicong@kylinos.cn>

list_count_nodes() was introduced in v6.5 to count the number of
nodes in a struct list_head. Provide an inline backport using
list_for_each() for older kernels.

Signed-off-by: Yi Cong <yicong@kylinos.cn>
---
 backport/backport-include/linux/list.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 backport/backport-include/linux/list.h

diff --git a/backport/backport-include/linux/list.h b/backport/backport-include/linux/list.h
new file mode 100644
index 00000000..47d8d24f
--- /dev/null
+++ b/backport/backport-include/linux/list.h
@@ -0,0 +1,25 @@
+#ifndef __BACKPORT_LINUX_LIST_H
+#define __BACKPORT_LINUX_LIST_H
+#include_next <linux/list.h>
+#include <linux/version.h>
+
+#if LINUX_VERSION_IS_LESS(6,5,0)
+/**
+ * list_count_nodes - count nodes in the list
+ * @head:	the head for your list.
+ *
+ * Introduced in v6.5. Provide a backport for older kernels.
+ */
+static inline size_t list_count_nodes(struct list_head *head)
+{
+	struct list_head *pos;
+	size_t count = 0;
+
+	list_for_each(pos, head)
+		count++;
+
+	return count;
+}
+#endif
+
+#endif /* __BACKPORT_LINUX_LIST_H */
-- 
2.43.0