MTD map access: Fix calculation of the number of longs in a bus access

Patch from Ben Dooks <ben-mtd@fluff.org>
Signed-Off-By: David Woodhouse <dwmw2@infradead.org>

include/linux/mtd/map.h

 
 /* Overhauled routines for dealing with different mmap regions of flash */
-/* $Id: map.h,v 1.43 2004/07/14 13:30:27 dwmw2 Exp $ */
+/* $Id: map.h,v 1.45 2004/09/21 14:31:17 bjd Exp $ */
 
 #ifndef __LINUX_MTD_MAP_H__
 #define __LINUX_MTD_MAP_H__
@@ -8,6 +8,7 @@
 #include <linux/config.h>
 #include <linux/types.h>
 #include <linux/list.h>
+#include <linux/mtd/compatmac.h>
 #include <asm/unaligned.h>
 #include <asm/system.h>
 #include <asm/io.h>
@@ -55,6 +56,11 @@
 #define map_bankwidth_is_4(map) (0)
 #endif
 
+/* ensure we never evaluate anything shorted than an unsigned long
+ * to zero, and ensure we'll never miss the end of an comparison (bjd) */
+
+#define map_calc_words(map) ((map_bankwidth(map) + (sizeof(unsigned long)-1))/ sizeof(unsigned long))
+
 #ifdef CONFIG_MTD_MAP_BANK_WIDTH_8
 # ifdef map_bankwidth
 #  undef map_bankwidth
@@ -63,12 +69,12 @@
 #   undef map_bankwidth_is_large
 #   define map_bankwidth_is_large(map) (map_bankwidth(map) > BITS_PER_LONG/8)
 #   undef map_words
-#   define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#   define map_words(map) map_calc_words(map)
 #  endif
 # else
 #  define map_bankwidth(map) 8
 #  define map_bankwidth_is_large(map) (BITS_PER_LONG < 64)
-#  define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#  define map_words(map) map_calc_words(map)
 # endif
 #define map_bankwidth_is_8(map) (map_bankwidth(map) == 8)
 #undef MAX_MAP_BANKWIDTH
@@ -84,11 +90,11 @@
 #  undef map_bankwidth_is_large
 #  define map_bankwidth_is_large(map) (map_bankwidth(map) > BITS_PER_LONG/8)
 #  undef map_words
-#  define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#  define map_words(map) map_calc_words(map)
 # else
 #  define map_bankwidth(map) 16
 #  define map_bankwidth_is_large(map) (1)
-#  define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#  define map_words(map) map_calc_words(map)
 # endif
 #define map_bankwidth_is_16(map) (map_bankwidth(map) == 16)
 #undef MAX_MAP_BANKWIDTH
@@ -104,11 +110,11 @@
 #  undef map_bankwidth_is_large
 #  define map_bankwidth_is_large(map) (map_bankwidth(map) > BITS_PER_LONG/8)
 #  undef map_words
-#  define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#  define map_words(map) map_calc_words(map)
 # else
 #  define map_bankwidth(map) 32
 #  define map_bankwidth_is_large(map) (1)
-#  define map_words(map) (map_bankwidth(map) / sizeof(unsigned long))
+#  define map_words(map) map_calc_words(map)
 # endif
 #define map_bankwidth_is_32(map) (map_bankwidth(map) == 32)
 #undef MAX_MAP_BANKWIDTH