Btrfs-progs: cleanup duplicated division functions

div_factor 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.

[Eric Sandeen: port kernel commit 3fed40c to userspace]

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

3 files changed, 35 insertions, 17 deletions

diff --git a/extent-tree.c b/extent-tree.c
index 63b1a386..e4582682 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -27,6 +27,7 @@
 #include "crc32c.h"
 #include "volumes.h"
 #include "free-space-cache.h"
+#include "math.h"
 
 #define PENDING_EXTENT_INSERT 0
 #define PENDING_EXTENT_DELETE 1
@@ -300,15 +301,6 @@ wrapped:
 	goto again;
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-	if (factor == 10)
-		return num;
-	num *= factor;
-	num /= 10;
-	return num;
-}
-
 static int block_group_state_bits(u64 flags)
 {
 	int bits = 0;
diff --git a/math.h b/math.h
new file mode 100644
index 00000000..482dba33
--- /dev/null
+++ b/math.h
@@ -0,0 +1,33 @@
+
+/*
+ * 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
+
+static inline u64 div_factor(u64 num, int factor)
+{
+	if (factor == 10)
+		return num;
+	num *= factor;
+	num /= 10;
+	return num;
+}
+
+#endif
diff --git a/volumes.c b/volumes.c
index 0ff22833..10fdc487 100644
--- a/volumes.c
+++ b/volumes.c
@@ -29,6 +29,7 @@
 #include "transaction.h"
 #include "print-tree.h"
 #include "volumes.h"
+#include "math.h"
 
 struct stripe {
 	struct btrfs_device *dev;
@@ -630,14 +631,6 @@ int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
-static u64 div_factor(u64 num, int factor)
-{
-	if (factor == 10)
-		return num;
-	num *= factor;
-	return num / 10;
-}
-
 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
 			       int sub_stripes)
 {