[PATCH 02/10] workqueue: remove unneeded check

[Lai Jiangshan]

Since we always pass flush responsibility to next, we will not deprive it,
now the ->first_flusher can only be changed by the first_flusher, no one
can change it, no race as 4ce48b37 said.

Remove the check introduced by 4ce48b37, use BUG_ON() instead.

Also move "wq->first_flusher = NULL;" later.

This patch doesn't make any functional difference.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
---
 kernel/workqueue.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 360b7e2..acd9e2f 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2682,12 +2682,7 @@ void flush_workqueue(struct workqueue_struct *wq)
 
 	mutex_lock(&wq->flush_mutex);
 
-	/* we might have raced, check again with mutex held */
-	if (wq->first_flusher != &this_flusher)
-		goto out_unlock;
-
-	wq->first_flusher = NULL;
-
+	BUG_ON(wq->first_flusher != &this_flusher);
 	BUG_ON(!list_empty(&this_flusher.list));
 	BUG_ON(wq->flush_color != this_flusher.flush_color);
 
@@ -2728,6 +2723,7 @@ void flush_workqueue(struct workqueue_struct *wq)
 
 		if (list_empty(&wq->flusher_queue)) {
 			BUG_ON(wq->flush_color != wq->work_color);
+			wq->first_flusher = NULL;
 			break;
 		}
 
-- 
1.7.4.4

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