From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B97E4C11F66 for ; Tue, 29 Jun 2021 09:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97E1761CC1 for ; Tue, 29 Jun 2021 09:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232662AbhF2JEB (ORCPT ); Tue, 29 Jun 2021 05:04:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24135 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232591AbhF2JEA (ORCPT ); Tue, 29 Jun 2021 05:04:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624957291; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pCMVXVrREB+3xGNYng722JG4/x5ib1E9Ik1DbsMH2eo=; b=XvP2DgnLTfPulSVOprFj2Sy72RsqC2V+WuaBzVxit+av8Uqh5NJRprFl1hQHeXxLASHvcG Kpujbvl45hqaFjf36UxoWWZ82dmSi0fuBP7WR+xV72eBWT5Eoh6BH8ckJrwi3ybrSySwg1 b1EGigmfBqfvoQV1eObSQ99DxsPTS1U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-576---DtsV0JMHiHA9ooIgDEmw-1; Tue, 29 Jun 2021 05:01:29 -0400 X-MC-Unique: --DtsV0JMHiHA9ooIgDEmw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A5ED0BBF0B; Tue, 29 Jun 2021 09:01:28 +0000 (UTC) Received: from T590 (ovpn-13-8.pek2.redhat.com [10.72.13.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6FFBC5C1D1; Tue, 29 Jun 2021 09:01:21 +0000 (UTC) Date: Tue, 29 Jun 2021 17:01:16 +0800 From: Ming Lei To: Daniel Wagner Cc: Wen Xiong , james.smart@broadcom.com, linux-kernel@vger.kernel.org, sagi@grimberg.me, wenxiong@linux.vnet.ibm.com Subject: Re: [PATCH 1/1] block: System crashes when cpu hotplug + bouncing port Message-ID: References: <1624850072-17776-1-git-send-email-wenxiong@linux.vnet.ibm.com> <20210628090703.apaowrsazl53lza4@beryllium.lan> <71d1ce491ed5056bfa921f0e14fa646d@imap.linux.ibm.com> <20210629082542.vm3yh6k36d2zh3k5@beryllium.lan> <20210629083549.unco3f7atybqypw3@beryllium.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210629083549.unco3f7atybqypw3@beryllium.lan> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 29, 2021 at 10:35:49AM +0200, Daniel Wagner wrote: > On Tue, Jun 29, 2021 at 10:25:43AM +0200, Daniel Wagner wrote: > > On Tue, Jun 29, 2021 at 11:47:55AM +0800, Ming Lei wrote: > > > > >>data.ctx = __blk_mq_get_ctx(q, cpu); > > > > cpu=2048 if hctx_idx = 4 > > > > > > Yeah, that is the issue I mentioned, any CPU in hctx->cpumask becomes > > > offline, please try the following patch and see if it makes a > > > difference: > > > > Given that cpumask_first_and() will return nr_cpu_ids in this case, > > can't we just bail out here and have to caller handle the error? > > To answer my own question, you want to avoid adding the if into the > hotpath. No, this way fails the request allocation, which isn't expected from NVMe fc/rdma/tcp/loop, since io queue can't be connected in this way. Thanks, Ming