From 8b70f45e2eb275da886b9c9dee190436d12d876a Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Tue, 2 Jun 2015 08:35:10 +0900 Subject: [PATCH] null_blk: restart request processing on completion handler 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 Cc: Jens Axboe Signed-off-by: Jens Axboe --- 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 6f0a58e7613d..6f9b7534928e 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; }