1 files changed, 7 insertions, 1 deletions

diff --git a/arch/sh/include/asm/fixmap.h b/arch/sh/include/asm/fixmap.h
index 76c5a3099cb8..5ac1e40a511c 100644
--- a/arch/sh/include/asm/fixmap.h
+++ b/arch/sh/include/asm/fixmap.h
@@ -46,9 +46,15 @@
  * fix-mapped?
  */
 enum fixed_addresses {
+        /*
+         * The FIX_CMAP entries are used by kmap_coherent() to get virtual
+         * addresses which are of a known color, and so their values are
+         * important. __fix_to_virt(FIX_CMAP_END - n) must give an address
+         * which is the same color as a page (n<<PAGE_SHIFT).
+         */
 #define FIX_N_COLOURS 8
         FIX_CMAP_BEGIN,
-        FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS),
+        FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1,
         FIX_UNCACHED,
 #ifdef CONFIG_HIGHMEM
         FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */