1 files changed, 47 insertions, 0 deletions

diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h
new file mode 100644
index 000000000000..23c1ec79a31b
--- /dev/null
+++ b/include/linux/flex_array.h
@@ -0,0 +1,47 @@
+#ifndef _FLEX_ARRAY_H
+#define _FLEX_ARRAY_H
+
+#include <linux/types.h>
+#include <asm/page.h>
+
+#define FLEX_ARRAY_PART_SIZE PAGE_SIZE
+#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE
+
+struct flex_array_part;
+
+/*
+ * This is meant to replace cases where an array-like
+ * structure has gotten too big to fit into kmalloc()
+ * and the developer is getting tempted to use
+ * vmalloc().
+ */
+
+struct flex_array {
+        union {
+                struct {
+                        int element_size;
+                        int total_nr_elements;
+                        struct flex_array_part *parts[0];
+                };
+                /*
+                 * This little trick makes sure that
+                 * sizeof(flex_array) == PAGE_SIZE
+                 */
+                char padding[FLEX_ARRAY_BASE_SIZE];
+        };
+};
+
+#define FLEX_ARRAY_INIT(size, total) { { {\
+        .element_size = (size),         \
+        .total_nr_elements = (total),   \
+} } }
+
+struct flex_array *flex_array_alloc(int element_size, int total, gfp_t flags);
+int flex_array_prealloc(struct flex_array *fa, int start, int end, gfp_t flags);
+void flex_array_free(struct flex_array *fa);
+void flex_array_free_parts(struct flex_array *fa);
+int flex_array_put(struct flex_array *fa, int element_nr, void *src,
+                gfp_t flags);
+void *flex_array_get(struct flex_array *fa, int element_nr);
+
+#endif /* _FLEX_ARRAY_H */