Re: [dpdk-dev] [PATCH 5/7] ethdev: do nothing if all-multicast mode is applied again

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 9/24/19 11:36 AM, Ferruh Yigit wrote:
> On 9/9/2019 1:13 PM, Andrew Rybchenko wrote:
>> Since driver callbacks return status code now, there is no necessity
>> to enable or disable all-multicast mode once again if it is already
>> successfully enabled or disabled.
>>
>> Configuration restore at startup tries to ensure that configured
>> all-multicast mode is applied and start will return error if it fails.
>>
>> Also it avoids theoretical cases when already configured all-multicast
>> mode is applied once again and fails. In this cases it is unclear
>> which value should be reported on get (configured or opposite).
>>
>> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> ---
>>   lib/librte_ethdev/rte_ethdev.c | 40 ++++++++++++++++++++--------------
>>   1 file changed, 24 insertions(+), 16 deletions(-)
>>
>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>> index 8115226c91..e1921e8225 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -1416,16 +1416,22 @@ rte_eth_dev_config_restore(struct rte_eth_dev *dev,
>>   	}
>>   
>>   	/* replay all multicast configuration */
>> -	if (rte_eth_allmulticast_get(port_id) == 1) {
>> -		ret = rte_eth_allmulticast_enable(port_id);
>> +	/*
>> +	 * use callbacks directly since we don't need port_id check and
>> +	 * would like to bypass the same value set
>> +	 */
>> +	if (rte_eth_allmulticast_get(port_id) == 1 &&
>> +	    *dev->dev_ops->allmulticast_enable != NULL) {
>> +		ret = (*dev->dev_ops->allmulticast_enable)(dev);
> I am for using the API here, it is more abstract instead of adding the dev_ops
> null checks etc. Will there be any downside to use the API?

API does not call operation if value matches and it will exactly match here
for sure since we just get it and applying once again.
Can't say that I like usage callback directly here, but it looks acceptable
for me. I've tried to clarify why it is done this way in the comment above.

> <...>
>
>> @@ -1962,16 +1968,17 @@ int
>>   rte_eth_allmulticast_enable(uint16_t port_id)
>>   {
>>   	struct rte_eth_dev *dev;
>> -	uint8_t old_allmulticast;
>> -	int diag;
>> +	int diag = 0;
>>   
>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>>   	dev = &rte_eth_devices[port_id];
>>   
>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->allmulticast_enable, -ENOTSUP);
>> -	old_allmulticast = dev->data->all_multicast;
>> -	diag = (*dev->dev_ops->allmulticast_enable)(dev);
>> -	dev->data->all_multicast = (diag == 0) ? 1 : old_allmulticast;
>> +
>> +	if (dev->data->all_multicast == 0) {
> What about adding this check even before 'allmulticast_enable' check, so if the
> multicast is already enabled why bother having dev_ops or not:
>
> if (dev->data->all_multicast == 1)
> 	return eth_err(port_id, diag);

Yes, it is a good idea. If so, similar fix up will be required for 
promiscuous mode.

>> +		diag = (*dev->dev_ops->allmulticast_enable)(dev);
>> +		dev->data->all_multicast = (diag == 0) ? 1 : 0;
>> +	}
>>   
>>   	return eth_err(port_id, diag);
>>   }
>> @@ -1980,18 +1987,19 @@ int
>>   rte_eth_allmulticast_disable(uint16_t port_id)
>>   {
>>   	struct rte_eth_dev *dev;
>> -	uint8_t old_allmulticast;
>> -	int diag;
>> +	int diag = 0;
>>   
>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>>   	dev = &rte_eth_devices[port_id];
>>   
>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->allmulticast_disable, -ENOTSUP);
>> -	old_allmulticast = dev->data->all_multicast;
>> -	dev->data->all_multicast = 0;
>> -	diag = (*dev->dev_ops->allmulticast_disable)(dev);
>> -	if (diag != 0)
>> -		dev->data->all_multicast = old_allmulticast;
>> +
>> +	if (dev->data->all_multicast == 1) {
> Same comment with above, can we move this check above..

Yes, will fix in the next version as well. Thanks for review.

>> +		dev->data->all_multicast = 0;
>> +		diag = (*dev->dev_ops->allmulticast_disable)(dev);
>> +		if (diag != 0)
>> +			dev->data->all_multicast = 1;
>> +	}
>>   
>>   	return eth_err(port_id, diag);
>>   }
>>