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=-3.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 3EEF3C43441 for ; Mon, 12 Nov 2018 02:32:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF989214DB for ; Mon, 12 Nov 2018 02:32:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZCpQ98Mb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF989214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730430AbeKLMXD (ORCPT ); Mon, 12 Nov 2018 07:23:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:45582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729612AbeKLMXD (ORCPT ); Mon, 12 Nov 2018 07:23:03 -0500 Received: from localhost (unknown [206.108.79.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 04B6320871; Mon, 12 Nov 2018 02:32:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541989925; bh=gkzsYs54GGYLBvF4p6dzXo6kbRPQZ+LyXv+aPjJeLYI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZCpQ98MbaFX7dEFQ4ubD2k4vc8oJyD/rUYsHqR6aEG0rKdSlk83BVvGWDNF0J+Vfj 0uxs3hXXek0ctai4Lfs9ioacY1I9BgoCLYjaAHaFuWfAL6fMm53o9Dkvb1a54L+Ooj L2NkgDl1QVN7dta6B/XFRzQJzyJ0Dv460V5ubnUY= Date: Sun, 11 Nov 2018 18:32:04 -0800 From: Greg Kroah-Hartman To: Bart Van Assche Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Sagi Grimberg , Christoph Hellwig , Sasha Levin Subject: Re: [PATCH 4.19 078/361] nvmet-rdma: use a private workqueue for delete Message-ID: <20181112023204.GC28618@kroah.com> References: <20181111221619.915519183@linuxfoundation.org> <20181111221630.901793876@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 11, 2018 at 05:27:05PM -0800, Bart Van Assche wrote: > On 11/11/18 2:17 PM, Greg Kroah-Hartman wrote: > > 4.19-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Sagi Grimberg > > > > [ Upstream commit 2acf70ade79d26b97611a8df52eb22aa33814cd4 ] > > > > Queue deletion is done asynchronous when the last reference on the queue > > is dropped. Thus, in order to make sure we don't over allocate under a > > connect/disconnect storm, we let queue deletion complete before making > > forward progress. > > > > However, given that we flush the system_wq from rdma_cm context which > > runs from a workqueue context, we can have a circular locking complaint > > [1]. Fix that by using a private workqueue for queue deletion. > > Hi Greg, > > You may want to drop this patch. A bug was discovered in this patch a few > days ago. I think not backporting this patch is better than backporting it. > See also the discussion at > http://lists.infradead.org/pipermail/linux-nvme/2018-November/020766.html. A > quote from that e-mail thread: "I think we need to revert 2acf70a > ("nvmet-rdma: use a private workqueue for delete") altogether because it > never made any difference..". Now dropped from the 4.18 and 4.19 queues, thanks. greg k-h