[dpdk-dev] 答复: [PATCH] net/virtio-user: support changing tap interface name

[Tan, Jianfeng]

On 3/28/2017 11:02 AM, Wenfeng Liu wrote:
> Hi Jianfeng,
>
> At 2017-03-28 10:05:11, "Tan, Jianfeng" <jianfeng.tan at intel.com> wrote:
>> Hi Wenfeng,
>>
>> Thank you for implementing this.
>>
>> On 3/11/2017 11:36 PM, Wenfeng Liu wrote:
>>> This patch adds a new option 'iface' to change the interface name of
>>> tap device with vhost-kernel as backend.
>>>
>>> Signed-off-by: Wenfeng Liu <liuwf at arraynetworks.com.cn>
>>> ---
>>>    drivers/net/virtio/virtio_user/virtio_user_dev.c | 12 ++++++++----
>>>    drivers/net/virtio/virtio_user/virtio_user_dev.h |  2 +-
>>>    drivers/net/virtio/virtio_user_ethdev.c          | 24
> +++++++++++++++++++++---
>>>    3 files changed, 30 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>> index 21ed00d..e7fd65f 100644
>>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
>>> @@ -193,9 +193,6 @@ int virtio_user_stop_device(struct virtio_user_dev
> *dev)
>>>    	for (i = 0; i < dev->max_queue_pairs; ++i)
>>>    		dev->ops->enable_qp(dev, i, 0);
>>>    
>>> -	free(dev->ifname);
>>> -	dev->ifname = NULL;
>> If we do not free it here, we need to free it at virtio_user_pmd_remove().
> Yes, I put the free in virtio_user_dev_uninit(), which will be called by
> virtio_user_pmd_remove().
>
>>> -
>>>    	return 0;
>>>    }
>>>    
>>> @@ -268,7 +265,7 @@ int virtio_user_stop_device(struct virtio_user_dev
> *dev)
>>>    
>>>    int
>>>    virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int
> queues,
>>> -		     int cq, int queue_size, const char *mac)
>>> +		     int cq, int queue_size, const char *mac, char **ifname)
>>>    {
>>>    	snprintf(dev->path, PATH_MAX, "%s", path);
>>>    	dev->max_queue_pairs = queues;
>>> @@ -277,6 +274,11 @@ int virtio_user_stop_device(struct virtio_user_dev
> *dev)
>>>    	dev->mac_specified = 0;
>>>    	parse_mac(dev, mac);
>>>    
>>> +	if (*ifname) {
>>> +		dev->ifname = *ifname;
>>> +		*ifname = NULL;
>>> +	}
>>> +
>>>    	if (virtio_user_dev_setup(dev) < 0) {
>>>    		PMD_INIT_LOG(ERR, "backend set up fails");
>>>    		return -1;
>>> @@ -327,6 +329,8 @@ int virtio_user_stop_device(struct virtio_user_dev
> *dev)
>>>    		free(dev->vhostfds);
>>>    		free(dev->tapfds);
>>>    	}
>>> +
>>> +	free(dev->ifname);
> Here is the free in virtio_user_dev_uninit().

Oops, I missed that.

>
>>>    }
>>>    
>>>    static uint8_t
>>> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> b/drivers/net/virtio/virtio_user/virtio_user_dev.h
>>> index 0d39f40..6ecb91e 100644
>>> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
>>> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
>>> @@ -69,7 +69,7 @@ struct virtio_user_dev {
>>>    int virtio_user_start_device(struct virtio_user_dev *dev);
>>>    int virtio_user_stop_device(struct virtio_user_dev *dev);
>>>    int virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int
> queues,
>>> -			 int cq, int queue_size, const char *mac);
>>> +			 int cq, int queue_size, const char *mac, char
> **ifname);
>>>    void virtio_user_dev_uninit(struct virtio_user_dev *dev);
>>>    void virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t
> queue_idx);
>>>    #endif
>>> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
> b/drivers/net/virtio/virtio_user_ethdev.c
>>> index 0b226ac..16d1526 100644
>>> --- a/drivers/net/virtio/virtio_user_ethdev.c
>>> +++ b/drivers/net/virtio/virtio_user_ethdev.c
>>> @@ -243,6 +243,8 @@
>>>    	VIRTIO_USER_ARG_PATH,
>>>    #define VIRTIO_USER_ARG_QUEUE_SIZE     "queue_size"
>>>    	VIRTIO_USER_ARG_QUEUE_SIZE,
>>> +#define VIRTIO_USER_ARG_INTERFACE_NAME "iface"
>>> +	VIRTIO_USER_ARG_INTERFACE_NAME,
>>>    	NULL
>>>    };
>>>    
>>> @@ -259,6 +261,9 @@
>>>    
>>>    	*(char **)extra_args = strdup(value);
>>>    
>>> +	if (!*(char **)extra_args)
>>> +		return -ENOMEM;
>>> +
>>>    	return 0;
>>>    }
>>>    
>>> @@ -347,6 +352,7 @@
>>>    	uint64_t cq = VIRTIO_USER_DEF_CQ_EN;
>>>    	uint64_t queue_size = VIRTIO_USER_DEF_Q_SZ;
>>>    	char *path = NULL;
>>> +	char *ifname = NULL;
>>>    	char *mac_addr = NULL;
>>>    	int ret = -1;
>>>    
>>> @@ -375,6 +381,15 @@
>>>    		goto end;
>>>    	}
>>>    
>>> +	if (rte_kvargs_count(kvlist, VIRTIO_USER_ARG_INTERFACE_NAME) == 1) {
>>> +		if (rte_kvargs_process(kvlist,
> VIRTIO_USER_ARG_INTERFACE_NAME,
>>> +				       &get_string_arg, &ifname) < 0) {
>>> +			PMD_INIT_LOG(ERR, "error to parse %s",
>>> +				     VIRTIO_USER_ARG_INTERFACE_NAME);
>>> +			goto end;
>>> +		}
>>> +	}
>>> +
>>>    	if (rte_kvargs_count(kvlist, VIRTIO_USER_ARG_MAC) == 1) {
>>>    		if (rte_kvargs_process(kvlist, VIRTIO_USER_ARG_MAC,
>>>    				       &get_string_arg, &mac_addr) < 0) {
>>> @@ -413,7 +428,7 @@
>>>    		cq = 1;
>>>    	}
>>>    
>>> -	if (queues > 1 && cq == 0) {
>>> +	if (queues > 1 && cq == VIRTIO_USER_DEF_CQ_EN) {
>> Any specific reason for above change? What if we set
>> VIRTIO_USER_DEF_CQ_EN=1 in future? I think zero is more clear.
> Because cq was initialized to VIRTIO_USER_DEF_CQ_EN in this function, I
> thought this comparison was intend to tell whether cq had been given a
> different value, so I used
> VIRTIO_USER_DEF_CQ_EN instead the magic number 0. Did I understand this
> correctly? If not, I am happy to change it back.

No, our purpose is not to check if cq is assigned a different value. We 
are checking if cq is enabled or not as mq requires cq.

Besides that, it looks good to me.

Reviewed-by: Jianfeng Tan <jianfeng.tan at intel.com>