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

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

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?

<...>

> @@ -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);

> +		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..

> +		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);
>  }
>