linux-kernel - Re: [PATCH 47/50] staging: omap-thermal: switch mutex to spinlock inside omap-bandgap

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Message-ID: <20130316142216.GR9138@mwanda>
Date:	Sat, 16 Mar 2013 17:22:16 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Eduardo Valentin <eduardo.valentin@...com>
Cc:	devel@...verdev.osuosl.org, gregkh@...uxfoundation.org,
	linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCH 47/50] staging: omap-thermal: switch mutex to spinlock
 inside omap-bandgap

On Sat, Mar 16, 2013 at 08:41:30AM -0400, Eduardo Valentin wrote:
> On 16-03-2013 04:59, Dan Carpenter wrote:
> >On Fri, Mar 15, 2013 at 09:00:35AM -0400, Eduardo Valentin wrote:
> >>@@ -502,9 +504,9 @@ int _omap_bandgap_write_threshold(struct omap_bandgap *bg_ptr, int id, int val,
> >>  	if (ret < 0)
> >>  		goto exit;
> >>
> >>-	mutex_lock(&bg_ptr->bg_mutex);
> >>+	spin_lock(&bg_ptr->lock);
> >
> >These need to disable interrupts because we take the spin lock in
> >the IRQ handler.
> 
> This IRQ gets masked at the IRQ controller level when served
> (ONE_SHOT). Not sure if your comment is applicable in this case..

Yes.  It still applies.  We need to disable IRQs from the current
CPU while we are holding a spin_lock which they will need.

regards,
dan carpenter

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