writeback: remove writeback_inodes_wbc

This was just an odd wrapper around writeback_inodes_wb.  Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 6981e4b..94a602e 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -614,8 +614,8 @@
 	return 1;
 }
 
-static void writeback_inodes_wb(struct bdi_writeback *wb,
-				struct writeback_control *wbc)
+void writeback_inodes_wb(struct bdi_writeback *wb,
+		struct writeback_control *wbc)
 {
 	int ret = 0;
 
@@ -660,13 +660,6 @@
 	/* Leave any unwritten inodes on b_io */
 }
 
-void writeback_inodes_wbc(struct writeback_control *wbc)
-{
-	struct backing_dev_info *bdi = wbc->bdi;
-
-	writeback_inodes_wb(&bdi->wb, wbc);
-}
-
 /*
  * The maximum number of pages to writeout in a single bdi flush/kupdate
  * operation.  We do this so we don't hold I_SYNC against an inode for
@@ -705,7 +698,6 @@
 			 struct wb_writeback_args *args)
 {
 	struct writeback_control wbc = {
-		.bdi			= wb->bdi,
 		.sb			= args->sb,
 		.sync_mode		= args->sync_mode,
 		.older_than_this	= NULL,