Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756410Ab2JQJDX (ORCPT ); Wed, 17 Oct 2012 05:03:23 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:44459 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756349Ab2JQJDV (ORCPT ); Wed, 17 Oct 2012 05:03:21 -0400 X-IronPort-AV: E=Sophos;i="4.80,599,1344182400"; d="scan'208";a="6016251" Message-ID: <507E75AA.2000605@cn.fujitsu.com> Date: Wed, 17 Oct 2012 17:08:58 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: KOSAKI Motohiro CC: Yasuaki Ishimatsu , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org Subject: Re: [PATCH 1/4] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove() References: <506C0AE8.40702@jp.fujitsu.com> <506C0C53.60205@jp.fujitsu.com> <50727984.20401@cn.fujitsu.com> <507E54AA.2080806@cn.fujitsu.com> In-Reply-To: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 17:02:57, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 17:02:58, Serialize complete at 2012/10/17 17:02:58 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2771 Lines: 74 At 10/17/2012 04:59 PM, KOSAKI Motohiro Wrote: > On Wed, Oct 17, 2012 at 2:48 AM, Wen Congyang wrote: >> At 10/13/2012 03:10 AM, KOSAKI Motohiro Wrote: >>>>>> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) >>>>>> +static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device) >>>>>> { >>>>>> int result; >>>>>> struct acpi_memory_info *info, *n; >>>>>> >>>>>> + list_for_each_entry_safe(info, n, &mem_device->res_list, list) { >>>>> >>>>> Which lock protect this loop? >>>> >>>> There is no any lock to protect it now... >>> >>> When iterate an item removal list, you should use lock for protecting from >>> memory corruption. >>> >>> >>> >>> >>>>>> +static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) >>>>>> +{ >>>>>> + int result; >>>>>> >>>>>> /* >>>>>> * Ask the VM to offline this memory range. >>>>>> * Note: Assume that this function returns zero on success >>>>>> */ >>>>> >>>>> Write function comment instead of this silly comment. >>>>> >>>>>> - list_for_each_entry_safe(info, n, &mem_device->res_list, list) { >>>>>> - if (info->enabled) { >>>>>> - result = remove_memory(info->start_addr, info->length); >>>>>> - if (result) >>>>>> - return result; >>>>>> - } >>>>>> - kfree(info); >>>>>> - } >>>>>> + result = acpi_memory_remove_memory(mem_device); >>>>>> + if (result) >>>>>> + return result; >>>>>> >>>>>> /* Power-off and eject the device */ >>>>>> result = acpi_memory_powerdown_device(mem_device); >>>>> >>>>> This patch move acpi_memory_powerdown_device() from ACPI_NOTIFY_EJECT_REQUEST >>>>> to release callback, but don't explain why. >>>> >>>> Hmm, it doesn't move the code. It just reuse the code in acpi_memory_powerdown_device(). >>> >>> Even if reuse or not reuse, you changed the behavior. If any changes >>> has no good rational, you cannot get an ack. >> >> I don't understand this? IIRC, the behavior isn't changed. > > Heh, please explain why do you think so. > We just introduce a function, and move codes from acpi_memory_disable_device() to the new function. We call the new function in acpi_memory_disable_device(), so the function acpi_memory_disable_device()'s behavior isn't changed. Maybe I don't understand what do you want to say. Thanks Wen Congyang -- 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/