Date: Tue, 13 Oct 2009 02:04:15 +0900 (JST)
Message-Id: <20091013.020415.78716977.anemo@mba.ocn.ne.jp>
To: alessandro.zummo@towertech.it
Cc: andy.sharp@lsi.com, thomas.hommel@gefanuc.com, rtc-linux@googlegroups.com,
       linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH 1/2] rtc-ds1511: Fix races around device registration
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
In-Reply-To: <20091012184739.46bb1052@i1501.lan.towertech.it>
References: <1255365461-5732-1-git-send-email-anemo@mba.ocn.ne.jp>
	<20091012184739.46bb1052@i1501.lan.towertech.it>
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On Mon, 12 Oct 2009 18:47:39 +0200, Alessandro Zummo <alessandro.zummo@towertech.it> wrote:
> > * Call dev_set_drvdata before rtc device creation
> > * Use its own spinlock instead of rtc->irq_lock
> 
>  why?

Because pdata->rtc must be initialized to use the irq_lock
(pdata->rtc->irq_lock).  There is a small window which rtc methods can
be called before pdata->rtc is initialized.

And there is no need use the irq_lock to protect hardware registers.
The driver's own spinlock shoule be enough.

---
Atsushi Nemoto
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