[PATCH]block: don't delay blk_run_queue_async

From: Shaohua Li
Date: Wed May 18 2011 - 04:42:36 EST


Let's check a scenario:
1. blk_delay_queue(q, SCSI_QUEUE_DELAY);
2. blk_run_queue_async();
the second one will became a noop, because q->delay_work already has
WORK_STRUCT_PENDING_BIT set, so the delayed work will still run after
SCSI_QUEUE_DELAY. But blk_run_queue_async actually hopes the delayed
work runs immediately.

Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
---
block/blk-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux/block/blk-core.c
===================================================================
--- linux.orig/block/blk-core.c 2011-05-18 16:17:54.000000000 +0800
+++ linux/block/blk-core.c 2011-05-18 16:29:38.000000000 +0800
@@ -316,8 +316,10 @@ EXPORT_SYMBOL(__blk_run_queue);
*/
void blk_run_queue_async(struct request_queue *q)
{
- if (likely(!blk_queue_stopped(q)))
+ if (likely(!blk_queue_stopped(q))) {
+ __cancel_delayed_work(&q->delay_work);
queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
+ }
}
EXPORT_SYMBOL(blk_run_queue_async);



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