diff --git a/fs/nls/nls_ascii.c b/fs/nls/nls_ascii.c
index 6993fae..7020e94 100644
--- a/fs/nls/nls_ascii.c
+++ b/fs/nls/nls_ascii.c
@@ -13,7 +13,7 @@
 #include <linux/nls.h>
 #include <linux/errno.h>
 
-static wchar_t charset2uni[256] = {
+static const wchar_t charset2uni[256] = {
 	/* 0x00*/
 	0x0000, 0x0001, 0x0002, 0x0003,
 	0x0004, 0x0005, 0x0006, 0x0007,
@@ -56,7 +56,7 @@
 	0x007c, 0x007d, 0x007e, 0x007f,
 };
 
-static unsigned char page00[256] = {
+static const unsigned char page00[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -75,11 +75,11 @@
 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
 };
 
-static unsigned char *page_uni2charset[256] = {
+static const unsigned char *const page_uni2charset[256] = {
 	page00,
 };
 
-static unsigned char charset2lower[256] = {
+static const unsigned char charset2lower[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -98,7 +98,7 @@
 	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, /* 0x78-0x7f */
 };
 
-static unsigned char charset2upper[256] = {
+static const unsigned char charset2upper[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -119,7 +119,7 @@
 
 static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
 {
-	unsigned char *uni2charset;
+	const unsigned char *uni2charset;
 	unsigned char cl = uni & 0x00ff;
 	unsigned char ch = (uni & 0xff00) >> 8;