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

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 9/24/2019 9:54 AM, Andrew Rybchenko wrote:
> 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.

Ah, right, we need it here as you explained. Thx.

> 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);
>>>   }
>>>
> 
>