Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753900AbdHUNt7 (ORCPT ); Mon, 21 Aug 2017 09:49:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46681 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753854AbdHUNt5 (ORCPT ); Mon, 21 Aug 2017 09:49:57 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 083FC7F7D0 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lvivier@redhat.com From: Laurent Vivier To: linux-kernel@vger.kernel.org Cc: Tejun Heo , linux-block@vger.kernel.org, Jens Axboe , Lai Jiangshan , Michael Ellerman , linuxppc-dev@lists.ozlabs.org Subject: [PATCH 2/2] blk-mq: don't use WORK_CPU_UNBOUND Date: Mon, 21 Aug 2017 15:49:51 +0200 Message-Id: <20170821134951.18848-2-lvivier@redhat.com> In-Reply-To: <20170821134951.18848-1-lvivier@redhat.com> References: <20170821134951.18848-1-lvivier@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 21 Aug 2017 13:49:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1098 Lines: 34 cpumask is the list of CPUs present when the queue is built. If a new CPU is hotplugged, this list is not updated, and when the scheduler asks for a CPU id, blk_mq_hctx_next_cpu() can return WORK_CPU_UNBOUND. And in this case _blk_mq_run_hw_queue() can be executed by the new CPU (that is not present in cpumask) and raises the following warning: WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && cpu_online(hctx->next_cpu)); To fix this problem, this patch modifies blk_mq_hctx_next_cpu() to only return a CPU id present in cpumask. Signed-off-by: Laurent Vivier --- block/blk-mq.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 4603b115e234..bdac1e654814 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1126,9 +1126,6 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) */ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) { - if (hctx->queue->nr_hw_queues == 1) - return WORK_CPU_UNBOUND; - if (--hctx->next_cpu_batch <= 0) { int next_cpu; -- 2.13.5