Re: [Lse-tech] [PATCH 09/11] Task watchers: Add support for per-task watchers

[Peter Williams <pwil3058@bigpond.net.au>]

Andrew Morton wrote:
> Matt Helsley <matthltc@us.ibm.com> wrote:
> > > > +static inline int notify_per_task_watchers(unsigned int val,
> > > > +					   struct task_struct *task)
> > > > +{
> > > > +	if (get_watch_event(val) != WATCH_TASK_INIT)
> > > > +		return raw_notifier_call_chain(&task->notify, val, task);
> > > > +	RAW_INIT_NOTIFIER_HEAD(&task->notify);
> > > > +	if (task->real_parent)
> > > > +		return raw_notifier_call_chain(&task->real_parent->notify,
> > > > +		   			       val, task);
> > > > +}
> > > It's possible for this task to exit without returning a result.
> > Assuming you meant s/task/function/:
> >
> > 	In the common case this will return a result because most tasks have a
> > real parent. The only exception should be the init task. However, the
> > init task does not "fork" from another task so this function will never
> > get called with WATCH_TASK_INIT and the init task.
> >
> > 	This means that if one wants to use per-task watchers to associate data
> > and a function call with *every* task, special care will need to be
> > taken to register with the init task.
>
> no......
>
> It's possible for this function to fall off the end without returning
> anything.  The compiler should have spat a warning.

I checked and it does.

--
Peter Williams                                   pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
 -- Ambrose Bierce
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