fs/fs-writeback.c: : make wb_do_writeback() as static

It's not used globally and could be static.
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fs-writeback.c

@@ -963,7 +963,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
 /*
  * Retrieve work items and do the writeback they describe
  */
-long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
+static long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
 {
 	struct backing_dev_info *bdi = wb->bdi;
 	struct wb_writeback_work *work;

include/linux/writeback.h

@@ -95,7 +95,6 @@ int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
 void sync_inodes_sb(struct super_block *);
 long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
 				enum wb_reason reason);
-long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
 void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
 void inode_wait_for_writeback(struct inode *inode);