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SubjectRe: [PATCH 2/2] enhance sysfs rfkill interface
On Fri, Mar 12, 2010 at 09:57:43PM +0100, Florian Mickler wrote:
> On Fri, 12 Mar 2010 10:22:09 -0800
> Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:
>
> > On Fri, Mar 12, 2010 at 07:03:08PM +0100, florian@mickler.org wrote:
> > >
> > > +static ssize_t rfkill_hard_show(struct device *dev,
> > > + struct device_attribute *attr,
> > > + char *buf)
> > > +{
> > > + struct rfkill *rfkill = to_rfkill(dev);
> > > + unsigned long flags;
> > > + u32 state;
> > > +
> > > + spin_lock_irqsave(&rfkill->lock, flags);
> > > + state = rfkill->state;
> > > + spin_unlock_irqrestore(&rfkill->lock, flags);
> >
> > Why exactly is this lock needed?
>
> The rfkill state is updated from multiple contexts... Am I overlooking
> smth obvious here?
>

You are not updating but reading... Are you concerned about seeing
a partial write to u32? It does not happen.

--
Dmitry


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