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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 00B55C48BDF for ; Fri, 18 Jun 2021 14:02:10 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A7B776120A for ; Fri, 18 Jun 2021 14:02:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7B776120A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8KE+Gpv7vDaYH7r+SVscjUkUtpK64mDC4YvCv7CP5yk=; b=ThRvOSbMufMMMG LTa9BmIPoYZRaCIdwM7hw27xoKoSXZ+RswO5nyoAZPts2H+QWvNNZ2lFRmy9bnFnkbSZL/JNUx7Mf qrdsKNOD0tXmGOtRzwd7z9PBKSPl9oWCG8skv+sNzyNOeNUdAobkEsbCjxIwOq/EXHdCjuAutZ5H2 30CWR944mHSZJlfL8+PKjx7AnqWf5rL2AvPx4NMbEOyzthAqh/DgakV3y4CkEvQ3hM2i5b+nABKPn fxa/Luv8wGG96L4rvaJGrmN4h/oXyMWJmhyOVq9ZKSFLajeVhy4bbumFQwbqVbt0RQl9ayn7Rv5b4 U03j1dGAZC2jIVktK5Dw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1luF4I-00EP8e-LS; Fri, 18 Jun 2021 14:01:58 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1luF4F-00EP6s-99 for linux-nvme@lists.infradead.org; Fri, 18 Jun 2021 14:01:57 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id D8BE068D08; Fri, 18 Jun 2021 16:01:47 +0200 (CEST) Date: Fri, 18 Jun 2021 16:01:47 +0200 From: Christoph Hellwig To: Ming Lei Cc: Christoph Hellwig , Jens Axboe , Jeffle Xu , Damien Le Moal , Keith Busch , Sagi Grimberg , "Wunderlich, Mark" , "Vasudevan, Anil" , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH 13/16] block: switch polling to be bio based Message-ID: <20210618140147.GA16258@lst.de> References: <20210615131034.752623-1-hch@lst.de> <20210615131034.752623-14-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210618_070155_512934_CD62FD96 X-CRM114-Status: GOOD ( 15.04 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Jun 16, 2021 at 10:30:23AM +0800, Ming Lei wrote: > Not sure disk is valid, we only hold the disk when opening a bdev, but > the bdev can be closed during polling. How? On a block device the caller needs to hold the block device open to read/write from it. On a file systems the file systems needs to be mounted, which also holds a bdev reference. > Also disk always holds one > reference on request queue, so if disk is valid, no need to grab queue's > refcnt in bio_poll(). But we need to avoid going into the lowlevel blk-mq polling code to not reference the potentially freed hctxs or tags as correctly pointed by yourself on the previous iteration. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme