Btrfs: cleanup duplicated division functions

div_factor{_fine} has been implemented for two times, cleanup it.
And I move them into a independent file named math.h because they are
common math functions.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

fs/btrfs/extent-tree.c

@@ -33,6 +33,7 @@
 #include "volumes.h"
 #include "locking.h"
 #include "free-space-cache.h"
+#include "math.h"
 
 #undef SCRAMBLE_DELAYED_REFS
 
@@ -649,24 +650,6 @@ void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 	rcu_read_unlock();
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-	if (factor == 10)
-		return num;
-	num *= factor;
-	do_div(num, 10);
-	return num;
-}
-
-static u64 div_factor_fine(u64 num, int factor)
-{
-	if (factor == 100)
-		return num;
-	num *= factor;
-	do_div(num, 100);
-	return num;
-}
-
 u64 btrfs_find_block_group(struct btrfs_root *root,
 			   u64 search_start, u64 search_hint, int owner)
 {

fs/btrfs/math.h

@@ -0,0 +1,44 @@
+
+/*
+ * Copyright (C) 2012 Fujitsu.  All rights reserved.
+ * Written by Miao Xie <miaox@cn.fujitsu.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __BTRFS_MATH_H
+#define __BTRFS_MATH_H
+
+#include <asm/div64.h>
+
+static inline u64 div_factor(u64 num, int factor)
+{
+	if (factor == 10)
+		return num;
+	num *= factor;
+	do_div(num, 10);
+	return num;
+}
+
+static inline u64 div_factor_fine(u64 num, int factor)
+{
+	if (factor == 100)
+		return num;
+	num *= factor;
+	do_div(num, 100);
+	return num;
+}
+
+#endif

fs/btrfs/volumes.c

@@ -25,7 +25,6 @@
 #include <linux/capability.h>
 #include <linux/ratelimit.h>
 #include <linux/kthread.h>
-#include <asm/div64.h>
 #include "compat.h"
 #include "ctree.h"
 #include "extent_map.h"
@@ -36,6 +35,7 @@
 #include "async-thread.h"
 #include "check-integrity.h"
 #include "rcu-string.h"
+#include "math.h"
 
 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
@@ -2338,18 +2338,6 @@ static int chunk_profiles_filter(u64 chunk_type,
 	return 1;
 }
 
-static u64 div_factor_fine(u64 num, int factor)
-{
-	if (factor <= 0)
-		return 0;
-	if (factor >= 100)
-		return num;
-
-	num *= factor;
-	do_div(num, 100);
-	return num;
-}
-
 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
 			      struct btrfs_balance_args *bargs)
 {
@@ -2514,15 +2502,6 @@ static int should_balance_chunk(struct btrfs_root *root,
 	return 1;
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-	if (factor == 10)
-		return num;
-	num *= factor;
-	do_div(num, 10);
-	return num;
-}
-
 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_balance_control *bctl = fs_info->balance_ctl;