From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tetsuya Mukawa <mukawa@igel.co.jp>
Subject: Re: [PATCH] vhost: provide vhost API to unregister vhost
 unix domain socket
Date: Thu, 18 Jun 2015 10:00:36 +0900
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On 2015/06/17 20:05, Xie, Huawei wrote:
> On 6/17/2015 12:17 PM, Tetsuya Mukawa wrote:
>> On 2015/06/02 10:50, Huawei Xie wrote:
>>> rte_vhost_driver_unregister will remove the listenfd from event list, and then close it.
>>>
>>> Signed-off-by: Huawei Xie <huawei.xie@intel.com>
>>> Signed-off-by: Peng Sun <peng.a.sun@intel.com>
>>> ---
>>>  
>>> +/**
>>> + * Unregister the specified vhost server
>>> + */
>>> +int
>>> +rte_vhost_driver_unregister(const char *path)
>>> +{
>>> +	int i;
>>> +	int count;
>>> +
>>> +	pthread_mutex_lock(&g_vhost_server.server_mutex);
>>> +
>>> +	for (i = 0; i < g_vhost_server.vserver_cnt; i++) {
>>> +		if (!strcmp(g_vhost_server.server[i]->path, path)) {
>>> +			fdset_del(&g_vhost_server.fdset,
>>> +				g_vhost_server.server[i]->listenfd);
>>> +
>>> +			close(g_vhost_server.server[i]->listenfd);
>>> +			free(g_vhost_server.server[i]->path);
>>> +			free(g_vhost_server.server[i]);
>>> +
>>> +			unlink(path);
>>> +
>>> +			count = --g_vhost_server.vserver_cnt;
>>> +			g_vhost_server.server[i] =
>>> +				g_vhost_server.server[count];
>>> +			g_vhost_server.server[count] =
>>> +				NULL;
>>> +			pthread_mutex_unlock(&g_vhost_server.server_mutex);
>>> +
>>> +			return 0;
>>> +		}
>>> +	}
>>> +	pthread_mutex_unlock(&g_vhost_server.server_mutex);
>>> +
>>> +	return -1;
>>> +}
>>> +
>>>
>> Hi Xie,
>>
>> It seems vserver_cnt is incremented when socket is registered, and
>> decremented when unregistered.
>> And this value is used for index value of g_vhost_server.server[ ], when
>> a new socket is registered.
> When we unregister a server at index x,  we will move the server at the
> tail of the array to the location x.
>> So I have a question about below case.
>>
>> Step1. socket0 is registered.
>> Step2: scoekt1 is registered.
>> Step3. socket0 is unregistered.
> When socket0 is unregistered, socket1  will be moved to location at index 0.

Thanks for explanation, I overlooked this behavior.
Now I don't have any concerns.

Thanks,
Tetsuya