From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60490 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753760AbeDQQBc (ORCPT ); Tue, 17 Apr 2018 12:01:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Haberland , Christian Borntraeger , Christoph Hellwig , Sagi Grimberg , Ming Lei , Jens Axboe Subject: [PATCH 4.16 42/68] blk-mq: make sure that correct hctx->next_cpu is set Date: Tue, 17 Apr 2018 17:57:55 +0200 Message-Id: <20180417155751.044663858@linuxfoundation.org> In-Reply-To: <20180417155749.341779147@linuxfoundation.org> References: <20180417155749.341779147@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit a1c735fb790745f94a359df45c11df4a69760389 upstream. >>>From commit 20e4d81393196 (blk-mq: simplify queue mapping & schedule with each possisble CPU), one hctx can be mapped from all offline CPUs, then hctx->next_cpu can be set as wrong. This patch fixes this issue by making hctx->next_cpu pointing to the first CPU in hctx->cpumask if all CPUs in hctx->cpumask are offline. Cc: Stefan Haberland Tested-by: Christian Borntraeger Reviewed-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Fixes: 20e4d81393196 ("blk-mq: simplify queue mapping & schedule with each possisble CPU") Cc: stable@vger.kernel.org Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-mq.c | 2 ++ 1 file changed, 2 insertions(+) --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2439,6 +2439,8 @@ static void blk_mq_map_swqueue(struct re */ hctx->next_cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); + if (hctx->next_cpu >= nr_cpu_ids) + hctx->next_cpu = cpumask_first(hctx->cpumask); hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; } }