[PATCH v4 2/6] mm/writeback: Don't check force_wait to handle bdi->work_list

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

Changelog:
 v3 - > v4:
    * add Tejun's Reviewed-by

After commit 839a8e86("writeback: replace custom worker pool implementation
with unbound workqueue"), bdi_writeback_workfn runs off bdi_writeback->dwork,
on each execution, it processes bdi->work_list and reschedules if there are
more things to do instead of flush any work that race with us existing. It is
unecessary to check force_wait in wb_do_writeback since it is always 0 after
the mentioned commit. This patch remove the force_wait in wb_do_writeback.

Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 fs/fs-writeback.c |   10 ++--------
 1 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f892dec..e15aa97 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -959,7 +959,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
 /*
  * Retrieve work items and do the writeback they describe
  */
-static long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
+static long wb_do_writeback(struct bdi_writeback *wb)
 {
 	struct backing_dev_info *bdi = wb->bdi;
 	struct wb_writeback_work *work;
@@ -967,12 +967,6 @@ static long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
 
 	set_bit(BDI_writeback_running, &wb->bdi->state);
 	while ((work = get_next_work_item(bdi)) != NULL) {
-		/*
-		 * Override sync mode, in case we must wait for completion
-		 * because this thread is exiting now.
-		 */
-		if (force_wait)
-			work->sync_mode = WB_SYNC_ALL;
 
 		trace_writeback_exec(bdi, work);
 
@@ -1021,7 +1015,7 @@ void bdi_writeback_workfn(struct work_struct *work)
 		 * rescuer as work_list needs to be drained.
 		 */
 		do {
-			pages_written = wb_do_writeback(wb, 0);
+			pages_written = wb_do_writeback(wb);
 			trace_writeback_pages_written(pages_written);
 		} while (!list_empty(&bdi->work_list));
 	} else {
-- 
1.7.5.4