Re: [PATCH net] tuntap: correct the return value in tun_set_iff()

[Michael S. Tsirkin]

On Tue, Apr 23, 2013 at 02:40:39PM +0800, Jason Wang wrote:
> commit (3be8fbab tuntap: fix error return code in tun_set_iff()) breaks the
> creation of multiqueue tuntap since it forbids to create more than one queues
> for a multiqueue tuntap device. We need return 0 instead -EBUSY here since we
> don't want to re-initialize the device when one or more queues has been already
> attached. Add a comment and correct the return value to zero.
> 
> Reported-by: Jerry Chu <hkchu@xxxxxxxxxx>
> Cc: Jerry Chu <hkchu@xxxxxxxxxx>
> Cc: Wei Yongjun <weiyj.lk@xxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

> ---
>  drivers/net/tun.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 729ed53..3a8977e 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1594,7 +1594,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
>  
>  		if (tun->flags & TUN_TAP_MQ &&
>  		    (tun->numqueues + tun->numdisabled > 1))
> -			return -EBUSY;
> +			/* One or more queue has already been attached, no need
> +			 * to initialize the device again.
> +			 */
> +			return 0;
>  	}
>  	else {
>  		char *name;
> -- 
> 1.7.1
> 
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