Re: [BUG] mm: bdi: export BDI attributes in sysfs

[Greg KH <greg@kroah.com>]

On Thu, May 15, 2008 at 03:05:10PM -0700, Arthur Jones wrote:
> Hi Greg, ...
> 
> On Thu, May 15, 2008 at 02:02:54PM -0700, Greg KH wrote:
> > On Thu, May 15, 2008 at 12:54:57PM -0700, Linus Torvalds wrote:
> > >
> > >
> > > On Thu, 15 May 2008, Miklos Szeredi wrote:
> > > >
> > > > Actually nothing should need protection.  The only problem AFAICS is
> > > > that the device_create()/dev_set_drvdata() interface is racy: somebody
> > > > can come in after the device has been created but before drvdata has
> > > > been set, and then we are in trouble.
> > >
> > > Well, I'm not sure that the locking should be at that level. Maybe the
> > > locking *should* be in the driver that does this. It may need to do other
> > > setup too, after all.
> > >
> > > Of course, doing a device_create_drvdata() thing might be the right
> > > solution, at least part of the time. Greg?
> > 
> > Here's a patch that is build tested only.
> > 
> > Can someone who can reproduce this let me know if it solves the problem?
> 
> Yes, this patch survives many power cycles
> without hitting the BUG...
> 
> Thanks for looking into this...

Great!

Thanks for testing this, I'll clean it up a bit more and send it to
Linus later this evening.  Gotta go take the kids to swimming lessons...

thanks,

greg k-h