Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753089Ab2EBGmZ (ORCPT ); Wed, 2 May 2012 02:42:25 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:36155 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752657Ab2EBGmW (ORCPT ); Wed, 2 May 2012 02:42:22 -0400 Date: Tue, 1 May 2012 22:06:25 -0700 From: Greg KH To: Jiang Liu Cc: Yinghai Lu , Kenji Kaneshige , Bjorn Helgaas , Don Dutile , Jiang Liu , Keping Chen , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH v2 04/19] PCI: serialize hotplug operations triggered by PCI hotplug sysfs interfaces Message-ID: <20120502050625.GB23579@kroah.com> References: <1335539820-11232-1-git-send-email-jiang.liu@huawei.com> <1335539820-11232-5-git-send-email-jiang.liu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1335539820-11232-5-git-send-email-jiang.liu@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1199 Lines: 46 On Fri, Apr 27, 2012 at 11:16:45PM +0800, Jiang Liu wrote: > + /* Avoid deadlock with pci_hp_deregister() */ > + while (!pci_hotplug_try_enter()) { > + /* Check whether the slot has been deregistered. */ > + if (list_empty(&slot->slot_list)) { > + retval = -ENODEV; > + goto exit_put; > + } > + msleep(1); > + } Oh my. Wow. {sigh} ick. My eyes hurt. And your cpu load just went crazy. You can now handle all of the nasty emails from sysadmins asking why their systems look like their load is high for no good reason. Not to mention all of the other issues here. My statement about not inventing new lock types has now been proven true. The fact that this would even be a chunk of code that was proposed to be merged makes me weep. You owe me a bottle of whatever you are drinking if you expect me to continue to review these patch submissions. I'm stopping here in the series, please rework this whole thing in a major way. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/