[PATCH] fix round_up/down

[Yinghai Lu <yinghai@kernel.org>]

From: H. Peter Anvin <hpa@zytor.com>

round_up with __type_of__
round_up use mask and | tricks from HPA and linus
    also move round_up/down to kernel.h

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/um/sys-x86_64/signal.c     |    2 --
 arch/x86/include/asm/proto.h    |    3 ---
 drivers/md/dm-exception-store.c |   10 ----------
 include/linux/kernel.h          |    6 ++++++
 4 files changed, 6 insertions(+), 15 deletions(-)

Index: linux-2.6/arch/x86/include/asm/proto.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/proto.h
+++ linux-2.6/arch/x86/include/asm/proto.h
@@ -22,7 +22,4 @@ extern int reboot_force;
 
 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);
 
-#define round_up(x, y) (((x) + (y) - 1) & ~((y) - 1))
-#define round_down(x, y) ((x) & ~((y) - 1))
-
 #endif /* _ASM_X86_PROTO_H */
Index: linux-2.6/include/linux/kernel.h
===================================================================
--- linux-2.6.orig/include/linux/kernel.h
+++ linux-2.6/include/linux/kernel.h
@@ -140,6 +140,7 @@ extern const char linux_proc_banner[];
 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 #define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
+#define rounddown(x, y) (((x) / (y)) * (y))
 #define DIV_ROUND_CLOSEST(x, divisor)(			\
 {							\
 	typeof(divisor) __divisor = divisor;		\
@@ -147,6 +148,11 @@ extern const char linux_proc_banner[];
 }							\
 )
 
+/* need y is 2^n */
+#define __round_mask(x,y) ((__typeof__(x))((y)-1))
+#define round_up(x,y) ((((x)-1) | __round_mask(x,y))+1)
+#define round_down(x,y) ((x) & ~__round_mask(x,y))
+
 #define _RET_IP_		(unsigned long)__builtin_return_address(0)
 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 
Index: linux-2.6/arch/um/sys-x86_64/signal.c
===================================================================
--- linux-2.6.orig/arch/um/sys-x86_64/signal.c
+++ linux-2.6/arch/um/sys-x86_64/signal.c
@@ -165,8 +165,6 @@ struct rt_sigframe
 	struct _fpstate fpstate;
 };
 
-#define round_down(m, n) (((m) / (n)) * (n))
-
 int setup_signal_stack_si(unsigned long stack_top, int sig,
 			  struct k_sigaction *ka, struct pt_regs * regs,
 			  siginfo_t *info, sigset_t *set)
Index: linux-2.6/drivers/md/dm-exception-store.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-exception-store.c
+++ linux-2.6/drivers/md/dm-exception-store.c
@@ -138,16 +138,6 @@ int dm_exception_store_type_unregister(s
 }
 EXPORT_SYMBOL(dm_exception_store_type_unregister);
 
-/*
- * Round a number up to the nearest 'size' boundary.  size must
- * be a power of 2.
- */
-static ulong round_up(ulong n, ulong size)
-{
-	size--;
-	return (n + size) & ~size;
-}
-
 static int set_chunk_size(struct dm_exception_store *store,
 			  const char *chunk_size_arg, char **error)
 {