writeback: remove writeback_control.more_io

When wbc.more_io was first introduced, it indicates whether there are
at least one superblock whose s_more_io contains more IO work. Now with
the per-bdi writeback, it can be replaced with a simple b_more_io test.

Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index e09592d..b225d0d 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -404,7 +404,6 @@
 		__field(	int,	pages_written		)
 		__field(	long,	pages_skipped		)
 		__field(	int,	sync_mode		)
-		__field(	char,	more_io			)	
 		__field(       pgoff_t,	writeback_index		)
 	),
 
@@ -415,16 +414,15 @@
 		__entry->pages_written	= pages_written;
 		__entry->pages_skipped	= wbc->pages_skipped;
 		__entry->sync_mode	= wbc->sync_mode;
-		__entry->more_io	= wbc->more_io;
 		__entry->writeback_index = inode->i_mapping->writeback_index;
 	),
 
 	TP_printk("dev %d,%d ino %lu ret %d pages_written %d pages_skipped %ld "
-		  " more_io %d sync_mode %d writeback_index %lu",
+		  "sync_mode %d writeback_index %lu",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino, __entry->ret,
 		  __entry->pages_written, __entry->pages_skipped,
-		  __entry->more_io, __entry->sync_mode,
+		  __entry->sync_mode,
 		  (unsigned long) __entry->writeback_index)
 );