Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934278AbYBHQk0 (ORCPT ); Fri, 8 Feb 2008 11:40:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933454AbYBHQjT (ORCPT ); Fri, 8 Feb 2008 11:39:19 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:35116 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933996AbYBHQjQ (ORCPT ); Fri, 8 Feb 2008 11:39:16 -0500 Subject: Re: [-mm PATCH] sysdev_unregister() should call kobject_del() From: Badari Pulavarty To: Greg KH , haveblue@us.ibm.com Cc: Andrew Morton , lkml In-Reply-To: <20080208054158.GA12742@kroah.com> References: <1202428618.26309.45.camel@dyn9047017100.beaverton.ibm.com> <20080208003825.GB27317@kroah.com> <1202433946.26309.47.camel@dyn9047017100.beaverton.ibm.com> <20080208045533.GA10988@kroah.com> <1202447322.13910.3.camel@badari-laptop.beaverton.ibm.com> <20080208054158.GA12742@kroah.com> Content-Type: text/plain Date: Fri, 08 Feb 2008 08:42:05 -0800 Message-Id: <1202488925.26309.60.camel@dyn9047017100.beaverton.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4946 Lines: 137 On Thu, 2008-02-07 at 21:41 -0800, Greg KH wrote: > On Thu, Feb 07, 2008 at 09:08:42PM -0800, Badari Pulavarty wrote: > > > > On Thu, 2008-02-07 at 20:55 -0800, Greg KH wrote: > > > On Thu, Feb 07, 2008 at 05:25:46PM -0800, Badari Pulavarty wrote: > > > > On Thu, 2008-02-07 at 16:38 -0800, Greg KH wrote: > > > > > On Thu, Feb 07, 2008 at 03:56:58PM -0800, Badari Pulavarty wrote: > > > > > > Hi Greg, > > > > > > > > > > > > While playing with hotplug memory remove on 2.6.24-mm1, I > > > > > > noticed that /sysfs directory entries are not getting removed. > > > > > > > > > > > > sysdev_unregister() used to call kobject_unregister(). > > > > > > But in 2.6.24-mm1, its only dropping the ref. It should > > > > > > call kobject_del() to remove the object. Correct ? > > > > > > > > > > > > With this change, the directories are getting removed > > > > > > correctly. Comments ? > > > > > > > > > > Ick, no, this shouldn't be needed, someone else must be holding a > > > > > reference to the kobject device somewhere. See the kobject documenation > > > > > for more info. > > > > > > > > > > I'll try to see where we grab 2 references... > > > > > > > > I will take a closer look then. I was taking easy way out :( > > > > > > Hm, I don't see anything obvious in the sys.c core. What code is > > > controlling these objects that you are creating and removing from the > > > system? > > > > add_memory_block()/register_memory() is creating sysfs entries > > for the memory blocks. > > > > I am trying to make use of remove_memory_block() to clean up > > sysfs entries. BTW, remove_memory_block() is never tested > > before, since we don't support memory remove yet. > > So how are you testing the sysdev removal logic then if you can't remove > memory? I am now adding code to remove memory, I am making use of the existing unregister_memory() code and ran into this. > > Oh, one thing, remove the link in unregister_memory, before you call > sysdev_unregister(). You are trying to get the name of a kobject, and > the whole object, that has just been blown away, not nice... I can add remove link before unregister() as you suggested. Regarding accessing kobject after freeing up, no one calls with "root". Why not clean it up first, like this ? Dave, are you okay with this ? Thanks, Badari register_memory()/unregister_memory() never gets called with "root". unregister_memory() is accessing kobject_name of the object just freed up. Since no one uses the code, lets take the code out. And also, make register_memory() static (since unregister_memory() is already static). Signed-off-by: Badari Pulavarty --- drivers/base/memory.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) Index: linux-2.6.24/drivers/base/memory.c =================================================================== --- linux-2.6.24.orig/drivers/base/memory.c 2008-02-07 16:59:52.000000000 -0800 +++ linux-2.6.24/drivers/base/memory.c 2008-02-08 08:26:33.000000000 -0800 @@ -62,8 +62,8 @@ void unregister_memory_notifier(struct n /* * register_memory - Setup a sysfs device for a memory block */ -int register_memory(struct memory_block *memory, struct mem_section *section, - struct node *root) +static +int register_memory(struct memory_block *memory, struct mem_section *section) { int error; @@ -71,26 +71,16 @@ int register_memory(struct memory_block memory->sysdev.id = __section_nr(section); error = sysdev_register(&memory->sysdev); - - if (root && !error) - error = sysfs_create_link(&root->sysdev.kobj, - &memory->sysdev.kobj, - kobject_name(&memory->sysdev.kobj)); - return error; } static void -unregister_memory(struct memory_block *memory, struct mem_section *section, - struct node *root) +unregister_memory(struct memory_block *memory, struct mem_section *section) { BUG_ON(memory->sysdev.cls != &memory_sysdev_class); BUG_ON(memory->sysdev.id != __section_nr(section)); sysdev_unregister(&memory->sysdev); - if (root) - sysfs_remove_link(&root->sysdev.kobj, - kobject_name(&memory->sysdev.kobj)); } /* @@ -361,7 +351,7 @@ static int add_memory_block(unsigned lon mutex_init(&mem->state_mutex); mem->phys_device = phys_device; - ret = register_memory(mem, section, NULL); + ret = register_memory(mem, section); if (!ret) ret = mem_create_simple_file(mem, phys_index); if (!ret) @@ -415,7 +405,7 @@ int remove_memory_block(unsigned long no mem_remove_simple_file(mem, state); mem_remove_simple_file(mem, phys_device); mem_remove_simple_file(mem, removable); - unregister_memory(mem, section, NULL); + unregister_memory(mem, section); return 0; } -- 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/