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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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