Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755107AbbGPM5q (ORCPT ); Thu, 16 Jul 2015 08:57:46 -0400 Received: from mga02.intel.com ([134.134.136.20]:46921 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751505AbbGPM5o (ORCPT ); Thu, 16 Jul 2015 08:57:44 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,488,1432623600"; d="scan'208";a="730041402" Date: Thu, 16 Jul 2015 18:29:30 +0530 From: Vinod Koul To: Jiang Liu Cc: Dave Jiang , Dan Williams , Jarkko Nikula , David Woodhouse , Tony Luck , x86@kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Subject: Re: [Patch V2] ioatdma: Ignore IOAT devices under hotplug-capable PCI host bridge Message-ID: <20150716125930.GP5086@localhost> References: <1436341305-19936-1-git-send-email-jiang.liu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1436341305-19936-1-git-send-email-jiang.liu@linux.intel.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: 1201 Lines: 27 On Wed, Jul 08, 2015 at 03:41:42PM +0800, Jiang Liu wrote: > The dmaengine core assumes that async DMA devices will only be removed > when they not used anymore, or it assumes dma_async_device_unregister() > will only be called by dma driver exit routines. But this assumption is > not true for the IOAT driver, which calls dma_async_device_unregister() > from ioat_remove(). So current IOAT driver doesn't support device > hot-removal because it may cause system crash to hot-remove an inuse > IOAT device. > > To support CPU socket hot-removal, all PCI devices, including IOAT > devices embedded in the socket, will be hot-removed. The idea solution > is to enhance the dmaengine core and IOAT driver to support hot-removal, > but that's too hard. > > This patch implements a hack to disable IOAT devices under hotplug-capable > CPU socket so it won't break socket hot-removal. Applied now, please ensure you use the right subsystem name -- ~Vinod -- 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/