f2fs: use macro for code readability

This patch introduces DEF_NIDS_PER_INODE/GET_ORPHAN_BLOCKS/F2FS_CP_PACKS macro
instead of numbers in code for readability.

change log from v1:
 o fix typo pointed out by Jaegeuk Kim.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 0ed77f3..08ed2b0 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -90,6 +90,8 @@
 #define CP_ORPHAN_PRESENT_FLAG	0x00000002
 #define CP_UMOUNT_FLAG		0x00000001
 
+#define F2FS_CP_PACKS		2	/* # of checkpoint packs */
+
 struct f2fs_checkpoint {
 	__le64 checkpoint_ver;		/* checkpoint block version number */
 	__le64 user_block_count;	/* # of user blocks */
@@ -126,6 +128,9 @@
  */
 #define F2FS_ORPHANS_PER_BLOCK	1020
 
+#define GET_ORPHAN_BLOCKS(n)	((n + F2FS_ORPHANS_PER_BLOCK - 1) / \
+					F2FS_ORPHANS_PER_BLOCK)
+
 struct f2fs_orphan_block {
 	__le32 ino[F2FS_ORPHANS_PER_BLOCK];	/* inode numbers */
 	__le32 reserved;	/* reserved */
@@ -147,6 +152,7 @@
 #define F2FS_NAME_LEN		255
 #define F2FS_INLINE_XATTR_ADDRS	50	/* 200 bytes for inline xattrs */
 #define DEF_ADDRS_PER_INODE	923	/* Address Pointers in an Inode */
+#define DEF_NIDS_PER_INODE	5	/* Node IDs in an Inode */
 #define ADDRS_PER_INODE(fi)	addrs_per_inode(fi)
 #define ADDRS_PER_BLOCK		1018	/* Address Pointers in a Direct Block */
 #define NIDS_PER_BLOCK		1018	/* Node IDs in an Indirect Block */
@@ -166,8 +172,9 @@
 #define MAX_INLINE_DATA		(sizeof(__le32) * (DEF_ADDRS_PER_INODE - \
 						F2FS_INLINE_XATTR_ADDRS - 1))
 
-#define INLINE_DATA_OFFSET	(PAGE_CACHE_SIZE - sizeof(struct node_footer) \
-			- sizeof(__le32) * (DEF_ADDRS_PER_INODE + 5 - 1))
+#define INLINE_DATA_OFFSET	(PAGE_CACHE_SIZE - sizeof(struct node_footer) -\
+				sizeof(__le32) * (DEF_ADDRS_PER_INODE + \
+				DEF_NIDS_PER_INODE - 1))
 
 struct f2fs_inode {
 	__le16 i_mode;			/* file mode */
@@ -197,7 +204,7 @@
 
 	__le32 i_addr[DEF_ADDRS_PER_INODE];	/* Pointers to data blocks */
 
-	__le32 i_nid[5];		/* direct(2), indirect(2),
+	__le32 i_nid[DEF_NIDS_PER_INODE];	/* direct(2), indirect(2),
 						double_indirect(1) node id */
 } __packed;