writeback: remove wb_list

The wb_list member of struct backing_device_info always has exactly one
element.  Just use the direct bdi->wb pointer instead and simplify some
code.

Also remove bdi_task_init which is now trivial to prepare for the next
patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index d5be1693ac93..d67989b8ba44 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -73,9 +73,9 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
          * If the default thread isn't there, make sure we add it. When
          * it gets created and wakes up, we'll run this work.
          */
-        if (unlikely(list_empty_careful(&bdi->wb_list)))
+        if (unlikely(!bdi->wb.task)) {
                 wake_up_process(default_backing_dev_info.wb.task);
-        else {
+        } else {
                 struct bdi_writeback *wb = &bdi->wb;
 
                 if (wb->task)