Re: [PATCH 2/2] enhance sysfs rfkill interface

[Dmitry Torokhov]

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@xxxxxxxxx> wrote:
> 
> > On Fri, Mar 12, 2010 at 07:03:08PM +0100, florian@xxxxxxxxxxx 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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