From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754228AbbFAXgd (ORCPT ); Mon, 1 Jun 2015 19:36:33 -0400 Received: from mail-pa0-f41.google.com ([209.85.220.41]:33679 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753989AbbFAXgQ (ORCPT ); Mon, 1 Jun 2015 19:36:16 -0400 From: Akinobu Mita To: linux-kernel@vger.kernel.org Cc: Akinobu Mita , Jens Axboe Subject: [PATCH 2/2] null_blk: restart request processing on completion handler Date: Tue, 2 Jun 2015 08:35:10 +0900 Message-Id: <1433201710-4284-2-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1433201710-4284-1-git-send-email-akinobu.mita@gmail.com> References: <1433201710-4284-1-git-send-email-akinobu.mita@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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