[dpdk-dev] [PATCH 1/2] net/tap: fix setting speed by argument

[Ferruh Yigit]

On 9/19/2017 5:45 AM, Pascal Mazon wrote:
> Hi,
> 
> The patch looks mainly ok to me.
> 
> I'll put some comments inline.
> 
> On 18/09/2017 20:47, Ferruh Yigit wrote:
>> From: Vipin Varghese <vipin.varghese at intel.com>
>>
>> tap speed argument is not working without generating any error.
> Can you describe the error, paste the log?
>>
>> This patch sets the configured speed during device start.
>>
>> Fixes: 02f96a0a82d1 ("net/tap: add TUN/TAP device PMD")
>> Cc: stable at dpdk.org
>>
>> Signed-off-by: Vipin Varghese <vipin.varghese at intel.com>
>> ---
>>  drivers/net/tap/rte_eth_tap.c | 27 +++++++++++++++++++++++++++
>>  drivers/net/tap/rte_eth_tap.h |  2 ++
>>  2 files changed, 29 insertions(+)
>>
>> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
>> index 01cba0fa1..00dad167f 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -545,6 +545,7 @@ tap_ioctl(struct pmd_internals *pmd, unsigned long request,
>>  	case SIOCGIFHWADDR:
>>  	case SIOCSIFHWADDR:
>>  	case SIOCSIFMTU:
>> +	case SIOCETHTOOL:
>>  		break;
>>  	default:
>>  		RTE_ASSERT(!"unsupported request type: must not happen");
>> @@ -585,6 +586,32 @@ static int
>>  tap_dev_start(struct rte_eth_dev *dev)
>>  {
>>  	int err;
>> +	struct ifreq ifr;
>> +	struct ethtool_cmd edata = {0};
>> +	struct pmd_internals *pmd = dev->data->dev_private;
>> +
>> +	/*set & get speed to device*/
>> +	edata.speed = pmd_link.link_speed;
>> +	edata.cmd = ETHTOOL_SSET;
>> +	ifr.ifr_data = (caddr_t)&edata;
>> +	if (tap_ioctl(pmd, SIOCETHTOOL, &ifr, 0, LOCAL_ONLY) < 0) {
> I think it would be best to also try setting the speed on the remote
> (tap_ioctl(REMOTE_ONLY)), but continue execution even if that fails.

Hi Pascal,

It looks like this ioctl fails to set tap speed. And as far as I can see speed
is hardcoded in kernel [1], do you know if it is possible to set speed of tap
interface?

Thanks,
ferruh

[1]
http://elixir.free-electrons.com/linux/v4.13.9/source/drivers/net/tun.c#L2460

>> +		RTE_LOG(WARNING, PMD,
>> +			"Could not set param speed %d for ifindex for %s.\n",
>> +				pmd_link.link_speed,
>> +				pmd->name);
>> +
>> +		/* fetch current speed of created device */
>> +		edata.cmd = ETHTOOL_GSET;
>> +		ifr.ifr_data = (caddr_t)&edata;
>> +		if (tap_ioctl(pmd, SIOCETHTOOL, &ifr, 0, LOCAL_ONLY) < 0)
>> +			return 0;
>> +
>> +		pmd_link.link_speed = edata.speed;
>> +		RTE_LOG(INFO, PMD, "get speed %d for ifindex for %s.\n",
> I would say "got".
> 
>> +			pmd_link.link_speed,
>> +			pmd->name);
>> +	}
>> +	dev->data->dev_link = pmd_link;
>>  
>>  	err = tap_intr_handle_set(dev, 1);
>>  	if (err)
>> diff --git a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h
>> index 928a0454e..3e91db4ae 100644
>> --- a/drivers/net/tap/rte_eth_tap.h
>> +++ b/drivers/net/tap/rte_eth_tap.h
>> @@ -40,6 +40,8 @@
>>  #include <net/if.h>
>>  
>>  #include <linux/if_tun.h>
>> +#include <linux/ethtool.h>
>> +#include <linux/sockios.h>
>>  
>>  #include <rte_ethdev.h>
>>  #include <rte_ether.h>
> These includes are only useful inside rte_eth_tap.c, I would put them
> there only.
>