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.m...@gmail.com>
Cc: Jens Axboe <ax...@fb.com>
---
drivers/block/null_blk.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 6f0a58e..6f9b753 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -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;
}
--
1.9.1
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