new helper: uaccess_kernel()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 9677a7c..b635273 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -266,7 +266,7 @@ static inline void set_fs(mm_segment_t fs)
 #define access_ok(type, addr, size)	(__range_ok(addr, size) == 0)
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
+	(uaccess_kernel() ? ~0UL : get_fs())
 
 /*
  * The "__xxx" versions of the user access functions do not verify the