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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 CA2F5C433DF for ; Wed, 1 Jul 2020 13:45:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99F2A206B6 for ; Wed, 1 Jul 2020 13:45:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iuP/lgMr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731230AbgGANpe (ORCPT ); Wed, 1 Jul 2020 09:45:34 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:41859 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731194AbgGANp2 (ORCPT ); Wed, 1 Jul 2020 09:45:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593611127; 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=DZxSkx34tkBmlaabILfMfIsOlNK9eGRAl15m0sVIO5M=; b=iuP/lgMrbRGY0wP/AYbu+J69a+BQAw+I7f8rMXVkqr9hiQQF9VhYZQR83TLBUsvmY6jYDc duSM8oU2mUA7t1FFGbsuv3qPaCm7ZgpMaO76EgnafLdbjjHy97qv6uBzIXKnuWtA89AYTC +gsERGyAaLhC57ogIO6Gvxq3zIbN5Us= 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-1-wsgrDM6yNca50KONfE81uQ-1; Wed, 01 Jul 2020 09:45:25 -0400 X-MC-Unique: wsgrDM6yNca50KONfE81uQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6F2D7800C60; Wed, 1 Jul 2020 13:45:23 +0000 (UTC) Received: from T590 (ovpn-12-33.pek2.redhat.com [10.72.12.33]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9D1D710013C0; Wed, 1 Jul 2020 13:45:17 +0000 (UTC) Date: Wed, 1 Jul 2020 21:45:12 +0800 From: Ming Lei To: Marek Szyprowski Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig , Bartlomiej Zolnierkiewicz Subject: Re: [PATCH] blk-mq: put driver tag when this request is completed Message-ID: <20200701134512.GA2443512@T590> References: <20200629094759.2002708-1-ming.lei@redhat.com> <57fb09b1-54ba-f3aa-f82c-d709b0e6b281@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57fb09b1-54ba-f3aa-f82c-d709b0e6b281@samsung.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Marek, On Wed, Jul 01, 2020 at 03:01:03PM +0200, Marek Szyprowski wrote: > Hi > > On 29.06.2020 11:47, Ming Lei wrote: > > It is natural to release driver tag when this request is completed by > > LLD or device since its purpose is for LLD use. > > > > One big benefit is that the released tag can be re-used quicker since > > bio_endio() may take too long. > > > > Meantime we don't need to release driver tag for flush request. > > > > Cc: Christoph Hellwig > > Signed-off-by: Ming Lei > > This patch landed recently in linux-next as commit 36a3df5a4574. Sadly > it causes a regression on one of my test systems (ARM 32bit, Samsung > Exynos5422 SoC based Odroid XU3 board with eMMC). The system boots fine > and then after a few seconds every executed command hangs. No > panic/ops/any other message. I will try to provide more information asap > I find something to share. Simple reverting it in linux-next is not > possible due to dependencies. What is the exact eMMC's driver code(include the host driver)? The usual way for handling completion is that host driver notifies block layer via blk_mq_complete_request() after the LLD specific handling for this request is done. However, there might be driver which may use rq->tag in its rq completion handler. I will see if the special case can be dealt with once you share the driver info. Thanks, Ming