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Date: Tue, 28 May 2013 17:42:48 +0200
From: Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de>
Message-ID: <20130528154248.GD14466@pandem0nium>
References: <179dd3afbd3ecdcd2144bd3016e1b01eaf0d5263.1369754967.git.mschiffer@universe-factory.net>
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In-Reply-To: <179dd3afbd3ecdcd2144bd3016e1b01eaf0d5263.1369754967.git.mschiffer@universe-factory.net>
Subject: Re: [B.A.T.M.A.N.] [PATCH maint] batman-adv: wait for rtnl in
 batadv_store_mesh_iface instead of failing if it is taken
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On Tue, May 28, 2013 at 05:32:32PM +0200, Matthias Schiffer wrote:
> The rtnl_lock in batadv_store_mesh_iface has been converted to a rtnl_try=
lock
> some time ago to avoid a possible deadlock between rtnl and s_active on r=
emoval
> of the sysfs nodes.
>=20
> The behaviour introduced by that was quite confusing as it could lead to =
the
> sysfs store to fail, making batman-adv setup scripts unreliable. As recen=
tly the
> sysfs removal was postponed to a worker not running with the rtnl taken, =
the
> deadlock can't occur any more and it is safe to change the trylock back t=
o a
> lock to make the sysfs store reliable again.
>=20
> Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

Reviewed-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>

Thanks for posting,
	Simon

> ---
>  sysfs.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>=20
> diff --git a/sysfs.c b/sysfs.c
> index 15a22ef..929e304 100644
> --- a/sysfs.c
> +++ b/sysfs.c
> @@ -582,10 +582,7 @@ static ssize_t batadv_store_mesh_iface(struct kobjec=
t *kobj,
>  	    (strncmp(hard_iface->soft_iface->name, buff, IFNAMSIZ) =3D=3D 0))
>  		goto out;
> =20
> -	if (!rtnl_trylock()) {
> -		ret =3D -ERESTARTSYS;
> -		goto out;
> -	}
> +	rtnl_lock();
> =20
>  	if (status_tmp =3D=3D BATADV_IF_NOT_IN_USE) {
>  		batadv_hardif_disable_interface(hard_iface,
> --=20
> 1.8.3
>=20

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