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Message-Id: <1202488925.26309.60.camel@dyn9047017100.beaverton.ibm.com>
Date: Fri, 08 Feb 2008 08:42:05 -0800
From: Badari Pulavarty <pbadari@...ibm.com>
To: Greg KH <greg@...ah.com>, haveblue@...ibm.com
Cc: Andrew Morton <akpm@...ux-foundation.org>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: [-mm PATCH] sysdev_unregister() should call kobject_del()
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 <pbadari@...ibm.com>
---
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;
}
--
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