[PATCH -next] writeback: remove unused delaration of bdi_async_bio_wq

[Xiu Jianfeng]

From: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>

It seems it was introduced by commit d3f77dfdc718 ("blkcg: implement
REQ_CGROUP_PUNT") unintentionally, but the definition does not exist,
remove it.

Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
---
 include/linux/backing-dev.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index fbad4fcd408e..1a97277f99b1 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -46,7 +46,6 @@ extern spinlock_t bdi_lock;
 extern struct list_head bdi_list;
 
 extern struct workqueue_struct *bdi_wq;
-extern struct workqueue_struct *bdi_async_bio_wq;
 
 static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
 {
-- 
2.34.1