From mboxrd@z Thu Jan  1 00:00:00 1970
From: Felipe Balbi <balbi@ti.com>
Subject: Re: [PATCH] cbus-tahvo: Add tahvo_write_reg locking
Date: Mon, 7 Nov 2011 08:10:45 +0200
Message-ID: <20111107061044.GB4265@legolas.emea.dhcp.ti.com>
References: <20111105171954.230d12fb@milhouse>
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To: Michael =?iso-8859-1?Q?B=FCsch?= <m@bues.ch>
Cc: Tony Lindgren <tony@atomide.com>, Felipe Balbi <balbi@ti.com>, linux-omap <linux-omap@vger.kernel.org>


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Hi,

On Sat, Nov 05, 2011 at 05:19:54PM +0100, Michael B=FCsch wrote:
> tahvo_write_reg() needs to take the mutex to avoid a race
> condition with tahvo_set_clear_reg_bits:
>=20
> tahvo_set_clear_reg_bits():   |  tahvo_write_reg():
>     __tahvo_read_reg()        |
>                               |      __tahvo_write_reg() <-- race here
>     __tahvo_write_reg()       |
>=20
> Signed-off-by: Michael Buesch <m@bues.ch>
>=20
> ---
>=20
> Index: linux-3.1/drivers/cbus/tahvo.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- linux-3.1.orig/drivers/cbus/tahvo.c	2011-11-05 17:03:39.598846119 +01=
00
> +++ linux-3.1/drivers/cbus/tahvo.c	2011-11-05 17:04:36.274768324 +0100
> @@ -104,7 +104,9 @@ void tahvo_write_reg(struct device *chil
>  {
>  	struct tahvo		*tahvo =3D dev_get_drvdata(child->parent);
> =20
> +	mutex_lock(&tahvo->mutex);
>  	__tahvo_write_reg(tahvo, reg, val);
> +	mutex_unlock(&tahvo->mutex);

yeah, my bad. The same should be done with tahvo_read_reg(). Care to
resend this patch adding the change to tahvo_read_reg() too...

--=20
balbi

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