[dpdk-dev] [PATCH 1/6] net/tap: use correct tap name

Ferruh Yigit ferruh.yigit at intel.com
Tue Jan 31 16:28:25 CET 2017

On 1/31/2017 2:23 PM, Pascal Mazon wrote:
> On 01/31/2017 02:06 PM, Ferruh Yigit wrote:> On 1/31/2017 9:42 AM, 
> Pascal Mazon wrote:
>>> dev->data->name contains "net_tap", the device driver name.
>> I see what patch does, just as a note to commit log:
>> AFAIK, "dev->data->name" is device name, and for this case it is
>> "net_tap#", like "net_tap0", "net_tap1" ...
>> "dev->data_drv_name" is the driver name which is "net_tap"
> Indeed, dev->data->name is the device name, looking like "net_tap#",
> with number increasing for each vdev.
> I'll put the following commit log line if that's ok:
>      dev->data->name contains the device name, e.g. "net_tap0".
>>> dev->data->dev_private->name contains the actual iface name,
>>> e.g. "dtap0".
>> Right, I agree this is correct comparing "dev->data->name"
>> But the problem is pmd->name is per eth_dev.
>> If I read code correct, for multiple queue support, each queue pair will
>> create a tap device, so each needs a different name.
>> So can't just use pmd->name. Need to create a name per queue pair, it
>> can be combination of pmd->name + "_" + queue_id? Or can keep a name per
>> queue pair, instead of eth_dev.
>> What do you think?
> Actually that's not exactly how it goes.
> Adding a queue to a netdevice requires to open("/dev/net/tun") and setting
> TUNSETIFF (through ioctl) on the resulting fd.
> That's the important part: queues for a given tap device must set TUNSETIFF
> with a common ifreq.ifr_name (in our case, pmd->name).
> This is best explained in the kernel doc, there:

Thank you for the clarification.
If so, why PMD keeps a fd per queue?

Overall, patch looks good except mentioned detail in commit log.

I suggest waiting Keith's patch, and rebase this set on top of it.


> [1] 
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/tuntap.txt#n108

More information about the dev mailing list