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

[Jiri Pirko <jiri@resnulli.us>]

Wed, Mar 27, 2019 at 08:45:38AM CET, jiri@resnulli.us wrote:
>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.

To correct myself, all is exposed by kernel, just not implemented in
userspace. I thought that generated port name would be good to have.
Not really good idea to generate it again in userspace. Anyway, I'll
leave this patch out for now, I can send it separatelly later on.


>
>>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,
>>