Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()

diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 8c9a6762061c..c9f6328d5dda 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c

@@ -12,18 +12,25 @@
  * for more details.
  */
 
+#include <linux/font.h>
 #include <linux/module.h>
-#include <linux/types.h>
 #include <linux/string.h>
+#include <linux/types.h>
+
+#include <asm/sections.h>
 #if defined(__mc68000__)
 #include <asm/setup.h>
 #endif
-#include <linux/font.h>
 
 /*
  * Helpers for font_data_t
  */
 
+static bool font_data_is_internal(font_data_t *fd)
+{
+	return is_kernel_rodata((unsigned long)fd);
+}
+
 /**
  * font_data_size - Return size of the font data in bytes
  * @fd: Font data

@@ -37,6 +44,32 @@ unsigned int font_data_size(font_data_t *fd)
 }
 EXPORT_SYMBOL_GPL(font_data_size);
 
+/**
+ * font_data_is_equal - Compares font data for equality
+ * @lhs: Left-hand side font data
+ * @rhs: Right-hand-size font data
+ *
+ * Font data is equal if is constain the same sequence of values. The
+ * helper also use the checksum, if both arguments contain it. Font data
+ * coming from different origins, internal or from user space, is never
+ * equal. Allowing this would break reference counting.
+ *
+ * Returns:
+ * True if the given font data is equal, false otherwise.
+ */
+bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs)
+{
+	if (font_data_is_internal(lhs) != font_data_is_internal(rhs))
+		return false;