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block: fix drain_all condition in blk_drain_queue()

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When trying to drain all requests, blk_drain_queue() checked only
q->rq.count[]; however, this only tracks REQ_ALLOCED requests.  This
patch updates blk_drain_queue() such that it looks at all the counters
and queues so that request_queue is actually empty on completion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2011-12-14 00:33:37 +01:00 committed by Jens Axboe
parent 34f6055c80
commit 481a7d6479
1 changed files with 18 additions and 6 deletions
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24
block/blk-core.c
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@ -358,7 +358,8 @@ EXPORT_SYMBOL(blk_put_queue);
void blk_drain_queue(struct request_queue *q, bool drain_all)
{
while (true) {
int nr_rqs;
bool drain = false;
int i;
spin_lock_irq(q->queue_lock);
@ -368,14 +369,25 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
__blk_run_queue(q);
if (drain_all)
nr_rqs = q->rq.count[0] + q->rq.count[1];
else
nr_rqs = q->rq.elvpriv;
drain |= q->rq.elvpriv;
/*
* Unfortunately, requests are queued at and tracked from
* multiple places and there's no single counter which can
* be drained. Check all the queues and counters.
*/
if (drain_all) {
drain |= !list_empty(&q->queue_head);
for (i = 0; i < 2; i++) {
drain |= q->rq.count[i];
drain |= q->in_flight[i];
drain |= !list_empty(&q->flush_queue[i]);
}
}
spin_unlock_irq(q->queue_lock);
if (!nr_rqs)
if (!drain)
break;
msleep(10);
}