Re: [PATCH 09/16] virtio-net: drop config_mutex

From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel@vger.kernel.org
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH 09/16] virtio-net: drop config_mutex
Date: Mon, 06 Oct 2014 15:46:15 +0400	[thread overview]
Message-ID: <54328107.5090400@cogentembedded.com> (raw)
In-Reply-To: <1412525038-15871-10-git-send-email-mst@redhat.com>

Hello.

On 10/5/2014 8:07 PM, Michael S. Tsirkin wrote:

> config_mutex served two purposes: prevent multiple concurrent config
> change handlers, and synchronize access to config_enable flag.

> Since commit dbf2576e37da0fcc7aacbfbb9fd5d3de7888a3c1
>      workqueue: make all workqueues non-reentrant
> all workqueues are non-reentrant, and config_enable
> is now gone.

> Get rid of the unnecessary lock.

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>   drivers/net/virtio_net.c | 7 +------
>   1 file changed, 1 insertion(+), 6 deletions(-)

> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index fa17afa..d80fef4 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
[...]
> @@ -1430,7 +1426,7 @@ static void virtnet_config_changed_work(struct work_struct *work)
>   		netif_tx_stop_all_queues(vi->dev);
>   	}
>   done:
> -	mutex_unlock(&vi->config_lock);
> +	return;

    There's no need for this *return*.

>   }
>
>   static void virtnet_config_changed(struct virtio_device *vdev)

WBR, Sergei