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null_blk: restart request processing on completion handler

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When irqmode=2 (IRQ completion handler is timer) and queue_mode=1
(Block interface to use is rq), the completion handler should restart
request handling for any pending requests on a queue because request
processing stops when the number of commands are queued more than
hw_queue_depth (null_rq_prep_fn returns BLKPREP_DEFER).

Without this change, the following command cannot finish.

	# modprobe null_blk irqmode=2 queue_mode=1 hw_queue_depth=1
	# fio --name=t --rw=read --size=1g --direct=1 \
	  --ioengine=libaio --iodepth=64 --filename=/dev/nullb0

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Akinobu Mita 2015-06-02 08:35:10 +09:00 committed by Jens Axboe
parent 419c21a3b6
commit 8b70f45e2e
1 changed files with 12 additions and 0 deletions
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12
drivers/block/null_blk.c
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@ -243,6 +243,17 @@ static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
cmd = container_of(entry, struct nullb_cmd, ll_list);
entry = entry->next;
end_cmd(cmd);
if (cmd->rq) {
struct request_queue *q = cmd->rq->q;
if (!q->mq_ops && blk_queue_stopped(q)) {
spin_lock(q->queue_lock);
if (blk_queue_stopped(q))
blk_start_queue(q);
spin_unlock(q->queue_lock);
}
}
} while (entry);
}
@ -334,6 +345,7 @@ static int null_rq_prep_fn(struct request_queue *q, struct request *req)
req->special = cmd;
return BLKPREP_OK;
}
blk_stop_queue(q);
return BLKPREP_DEFER;
}