Re: [patch net-next v2 11/12] net: devlink: expose phys port name

[Jiri Pirko <jiri@resnulli.us>]

Tue, Mar 26, 2019 at 09:35:58PM CET, jakub.kicinski@netronome.com wrote:
>On Tue, 26 Mar 2019 13:03:06 +0100, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@mellanox.com>
>> 
>> Currently, it is exposed via rtnetlink. But it is relevant to devlink
>> ports, so expose it here too.
>> 
>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>
>Why?  User space has access to all the components which are used to
>generate the name in a typed, structured form.  That's strictly

Nope. It does has access only to flavour. Not to port number for
example. So I thought either expose that or the generated name.

>superior to the string netdev string.
>
>Do you have some use in mind for the new attribute?
>
>> diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
>> index 5bb4ea67d84f..2d0365e45141 100644
>> --- a/include/uapi/linux/devlink.h
>> +++ b/include/uapi/linux/devlink.h
>> @@ -332,6 +332,8 @@ enum devlink_attr {
>>  	DEVLINK_ATTR_FLASH_UPDATE_FILE_NAME,	/* string */
>>  	DEVLINK_ATTR_FLASH_UPDATE_COMPONENT,	/* string */
>>  
>> +	DEVLINK_ATTR_PORT_PHYS_NAME,		/* string */
>> +
>>  	/* add new attributes above here, update the policy in devlink.c */
>>  
>>  	__DEVLINK_ATTR_MAX,
>> diff --git a/net/core/devlink.c b/net/core/devlink.c
>> index 6bbd07e3861e..356d7ee7c404 100644
>> --- a/net/core/devlink.c
>> +++ b/net/core/devlink.c
>> @@ -508,6 +508,57 @@ static void devlink_notify(struct devlink *devlink, enum devlink_command cmd)
>>  				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
>>  }
>>  
>> +static int __devlink_port_phys_port_name_get(struct devlink_port *devlink_port,
>> +					     char *name, size_t len)
>> +{
>> +	struct devlink_port_attrs *attrs = &devlink_port->attrs;
>> +	int n = 0;
>> +
>> +	if (!attrs->set)
>> +		return -EOPNOTSUPP;
>> +
>> +	switch (attrs->flavour) {
>> +	case DEVLINK_PORT_FLAVOUR_PHYSICAL:
>> +		if (!attrs->split)
>> +			n = snprintf(name, len, "p%u", attrs->port_number);
>> +		else
>> +			n = snprintf(name, len, "p%us%u", attrs->port_number,
>> +				     attrs->split_subport_number);
>> +		break;
>> +	case DEVLINK_PORT_FLAVOUR_CPU:
>> +	case DEVLINK_PORT_FLAVOUR_DSA:
>> +		/* As CPU and DSA ports do not have a netdevice associated
>> +		 * case should not ever happen.
>> +		 */
>> +		WARN_ON(1);
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (n >= len)
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static int devlink_nl_port_phys_port_name_put(struct sk_buff *msg,
>> +					      struct devlink_port *devlink_port)
>> +{
>> +	struct devlink_port_attrs *attrs = &devlink_port->attrs;
>> +	char phys_name[IFNAMSIZ];
>> +	int err;
>> +
>> +	if (attrs->flavour != DEVLINK_PORT_FLAVOUR_PHYSICAL)
>> +		return 0;
>> +
>> +	err = __devlink_port_phys_port_name_get(devlink_port,
>> +						phys_name, sizeof(phys_name));
>> +	if (err)
>> +		return err;
>> +	if (nla_put_string(msg, DEVLINK_ATTR_PORT_PHYS_NAME, phys_name))
>> +		return -EMSGSIZE;
>> +	return 0;
>> +}
>> +
>>  static int devlink_nl_port_attrs_put(struct sk_buff *msg,
>>  				     struct devlink_port *devlink_port)
>>  {
>> @@ -526,6 +577,9 @@ static int devlink_nl_port_attrs_put(struct sk_buff *msg,
>>  	if (nla_put_u32(msg, DEVLINK_ATTR_PORT_SPLIT_SUBPORT_NUMBER,
>>  			attrs->split_subport_number))
>>  		return -EMSGSIZE;
>> +	if (devlink_nl_port_phys_port_name_put(msg, devlink_port))
>> +		return -EMSGSIZE;
>> +
>>  	return 0;
>>  }
>>  
>> @@ -5414,38 +5468,6 @@ void devlink_port_attrs_set(struct devlink_port *devlink_port,
>>  }
>>  EXPORT_SYMBOL_GPL(devlink_port_attrs_set);
>>  
>> -static int __devlink_port_phys_port_name_get(struct devlink_port *devlink_port,
>> -					     char *name, size_t len)
>> -{
>> -	struct devlink_port_attrs *attrs = &devlink_port->attrs;
>> -	int n = 0;
>> -
>> -	if (!attrs->set)
>> -		return -EOPNOTSUPP;
>> -
>> -	switch (attrs->flavour) {
>> -	case DEVLINK_PORT_FLAVOUR_PHYSICAL:
>> -		if (!attrs->split)
>> -			n = snprintf(name, len, "p%u", attrs->port_number);
>> -		else
>> -			n = snprintf(name, len, "p%us%u", attrs->port_number,
>> -				     attrs->split_subport_number);
>> -		break;
>> -	case DEVLINK_PORT_FLAVOUR_CPU:
>> -	case DEVLINK_PORT_FLAVOUR_DSA:
>> -		/* As CPU and DSA ports do not have a netdevice associated
>> -		 * case should not ever happen.
>> -		 */
>> -		WARN_ON(1);
>> -		return -EINVAL;
>> -	}
>> -
>> -	if (n >= len)
>> -		return -EINVAL;
>> -
>> -	return 0;
>> -}
>> -
>>  int devlink_sb_register(struct devlink *devlink, unsigned int sb_index,
>>  			u32 size, u16 ingress_pools_count,
>>  			u16 egress_pools_count, u16 ingress_tc_count,
>