From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH 09/16] virtio-net: drop config_mutex
Date: Mon, 06 Oct 2014 16:07:32 +0400
Message-ID: <54328604.30403@cogentembedded.com>
References: <1412525038-15871-1-git-send-email-mst@redhat.com>
	<1412525038-15871-10-git-send-email-mst@redhat.com>
	<54328107.5090400@cogentembedded.com>
	<20141006115636.GA26184@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <virtualization-bounces@lists.linux-foundation.org>
In-Reply-To: <20141006115636.GA26184@redhat.com>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/virtualization>,
	<mailto:virtualization-request@lists.linux-foundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/virtualization/>
List-Post: <mailto:virtualization@lists.linux-foundation.org>
List-Help: <mailto:virtualization-request@lists.linux-foundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/virtualization>,
	<mailto:virtualization-request@lists.linux-foundation.org?subject=subscribe>
Sender: virtualization-bounces@lists.linux-foundation.org
Errors-To: virtualization-bounces@lists.linux-foundation.org
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org
List-Id: virtualization@lists.linuxfoundation.org

On 10/6/2014 3:56 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*.

> I know - it's removed by the follow-up patch.

    Yeah, I saw.

> It's formatted like this to make diff smaller
> and make review easier.

    Don't understand how adding this line makes diff smaller though...
You first need to add it and then to delete it, where's the save?

WBR, Sergei