Re: 2.6.21-rc suspend regression: sysfs deadlock

Cornelia Huck
2007-03-15T10:25:47Z

On Wed, 14 Mar 2007 15:23:10 -0400 (EDT),
Alan Stern <stern@rowland.harvard.edu> wrote:

> > > +struct other_task_struct {
> > > + struct kobject *kobj;
> > > + void (*func)(void *);
> > > + void *data;
> > > + struct work_struct work;
> > > +};
> > > +
> > > +static void other_task_work(struct work_struct *work)
> > > +{
> > > + struct other_task_struct *ots = container_of(work,
> > > + struct other_task_struct, work);
> > > +
> > > + (ots->func)(ots->data);
> > > + kobject_put(ots->kobj);
> > > + kfree(ots);
> > > +}
> >
> > The naming seems a bit unintuitive, but I don't have a good
> > alternative idea. Perhaps sysfs_work_struct, sysfs_delayed_work()?
>
> sysfs_work_struct is too generic; other parts of sysfs might also want to
> use workqueues for different purposes.

> I don't like calling it "delayed"-anything, because the operations aren't
> necessarily delayed! On an SMP system they might even execute before the
> sysfs_access_in_other_task() call returns. (Although the two examples we
> have so far can't do that because of lock contention.)

Sure. But then you shouldn't refer to "delay" in the comments for the
functions as well :)

> The major feature added here is that the work takes place in a different
> task's context, not that it is delayed. Hence the choice of names.

Hm. Perhaps device_schedule_access()?