Re: [PATCH] wlcore: move handling from hardirq to the irq thread function

[Felipe Balbi <balbi@ti.com>]

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On Mon, Mar 25, 2013 at 01:33:25PM +0200, Luciano Coelho wrote:
> On Mon, 2013-03-25 at 13:11 +0200, Felipe Balbi wrote:
> > On Mon, Mar 25, 2013 at 12:53:44PM +0200, Luciano Coelho wrote:
> > > Spin locks and completions are expensive in hard IRQ context and cause
> > > problems with RT kernels.  In RT kernels, both spin locks and
> > > completions can schedule(), so we can't use them in hard irq context.
> > > 
> > > Move handling code into the irq thread function to avoid that.
> > > 
> > > Reported-by: Gregoire Gentil <gregoire@alwaysinnovating.com>
> > > Signed-off-by: Luciano Coelho <coelho@ti.com>
> > > ---
> > >  drivers/net/wireless/ti/wlcore/main.c |   53 +++++++++++++--------------------
> > >  1 file changed, 21 insertions(+), 32 deletions(-)
> > > 
> > > diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
> > > index 248daa9..c2730a7 100644
> > > --- a/drivers/net/wireless/ti/wlcore/main.c
> > > +++ b/drivers/net/wireless/ti/wlcore/main.c
> > > @@ -651,6 +651,25 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
> > >  	unsigned long flags;
> > >  	struct wl1271 *wl = cookie;
> > >  
> > > +	/* complete the ELP completion */
> > > +	spin_lock_irqsave(&wl->wl_lock, flags);
> > > +	set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
> > > +	if (wl->elp_compl) {
> > > +		complete(wl->elp_compl);
> > > +		wl->elp_compl = NULL;
> > > +	}
> > > +
> > > +	if (test_bit(WL1271_FLAG_SUSPENDED, &wl->flags)) {
> > > +		/* don't enqueue a work right now. mark it as pending */
> > > +		set_bit(WL1271_FLAG_PENDING_WORK, &wl->flags);
> > > +		wl1271_debug(DEBUG_IRQ, "should not enqueue work");
> > > +		disable_irq_nosync(wl->irq);
> > > +		pm_wakeup_event(wl->dev, 0);
> > > +		spin_unlock_irqrestore(&wl->wl_lock, flags);
> > > +		return IRQ_HANDLED;
> > > +	}
> > > +	spin_unlock_irqrestore(&wl->wl_lock, flags);
> > 
> > I still think _irqrestore() here is wrong, since it will reenable the
> > IRQ line... other than that, it looks alright.
> 
> As we discussed earlier, it won't re-enable, since it was not enabled
> when we saved.  But, in any case, as we agreed, I'll send a separate
> patch removing it.  Don't want to mix two things in the same patch.

alright...

Reviewed-by: Felipe Balbi <balbi@ti.com>

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balbi

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