diff --git a/include/charset.h b/include/charset.h
index 4f7ae8fafd..020f8a90df 100644
--- a/include/charset.h
+++ b/include/charset.h
@@ -178,7 +178,7 @@ s32 utf_to_upper(const s32 code);
  * ReturnValue:		number of non-zero words.
  *			This is not the number of utf-16 letters!
  */
-size_t u16_strlen(const u16 *in);
+size_t u16_strlen(const void *in);
 
 /**
  * u16_strlen - count non-zero words
@@ -214,7 +214,7 @@ u16 *u16_strcpy(u16 *dest, const u16 *src);
  * @src:		source buffer (null terminated)
  * Return:		allocated new buffer on success, NULL on failure
  */
-u16 *u16_strdup(const u16 *src);
+u16 *u16_strdup(const void *src);
 
 /**
  * utf16_to_utf8() - Convert an utf16 string to utf8
diff --git a/lib/charset.c b/lib/charset.c
index 5e349ed5ee..72d745da4f 100644
--- a/lib/charset.c
+++ b/lib/charset.c
@@ -335,11 +335,16 @@ s32 utf_to_upper(const s32 code)
 	return ret;
 }
 
-size_t u16_strlen(const u16 *in)
+size_t u16_strlen(const void *in)
 {
-	size_t i;
-	for (i = 0; in[i]; i++);
-	return i;
+	const char *pos = in;
+	size_t ret;
+
+	for (; pos[0] || pos[1]; pos += 2)
+		;
+	ret = pos - (char *)in;
+	ret >>= 1;
+	return ret;
 }
 
 size_t u16_strnlen(const u16 *in, size_t count)
@@ -362,18 +367,18 @@ u16 *u16_strcpy(u16 *dest, const u16 *src)
 	return tmp;
 }
 
-u16 *u16_strdup(const u16 *src)
+u16 *u16_strdup(const void *src)
 {
 	u16 *new;
+	size_t len;
 
 	if (!src)
 		return NULL;
-
-	new = malloc((u16_strlen(src) + 1) * sizeof(u16));
+	len = (u16_strlen(src) + 1) * sizeof(u16);
+	new = malloc(len);
 	if (!new)
 		return NULL;
-
-	u16_strcpy(new, src);
+	memcpy(new, src, len);
 
 	return new;
 }