Re: [PATCH net-next 1/2] net: dsa: mv88e6xxx: Keep ATU/VTU violation statistics

[Florian Fainelli <f.fainelli@gmail.com>]

On 03/28/2018 12:33 PM, Andrew Lunn wrote:
> On Wed, Mar 28, 2018 at 11:17:19AM -0700, Florian Fainelli wrote:
>> On 03/27/2018 02:59 PM, Andrew Lunn wrote:
>>> Count the numbers of various ATU and VTU violation statistics and
>>> return them as part of the ethtool -S statistics.
>>>
>>> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
>>> ---
>>>  drivers/net/dsa/mv88e6xxx/chip.c        | 50 ++++++++++++++++++++++++++++-----
>>>  drivers/net/dsa/mv88e6xxx/chip.h        | 13 ++++++---
>>>  drivers/net/dsa/mv88e6xxx/global1_atu.c | 12 +++++---
>>>  drivers/net/dsa/mv88e6xxx/global1_vtu.c |  8 ++++--
>>>  drivers/net/dsa/mv88e6xxx/serdes.c      | 15 ++++++----
>>>  drivers/net/dsa/mv88e6xxx/serdes.h      |  8 +++---
>>>  6 files changed, 78 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
>>> index 9a5d786b4885..186021f98c5d 100644
>>> --- a/drivers/net/dsa/mv88e6xxx/chip.c
>>> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
>>> @@ -723,6 +723,24 @@ static int mv88e6320_stats_get_strings(struct mv88e6xxx_chip *chip,
>>>  					   STATS_TYPE_BANK0 | STATS_TYPE_BANK1);
>>>  }
>>>  
>>> +static const uint8_t *mv88e6xxx_atu_vtu_stats_strings[] = {
>>
>> Why not const char *?
> 
> The ethtool call passes i uint8_t *data to receive the copy into. I'm
> keeping it consistent.

Fair enough.

> 
>>> +static void mv88e6xxx_atu_vtu_get_strings(uint8_t *data)
>>> +{
>>> +	int i;
>>
>> unsigned int i?
> 
> I could do, but it seems unlikely it will overflow 31 bits.

The size cannot be negative, so unsigned int would seem like a natural
choice.

> 
>>> +
>>> +	for (i = 0; i < ARRAY_SIZE(mv88e6xxx_atu_vtu_stats_strings); i++)
>>> +		strlcpy(data + i * ETH_GSTRING_LEN,
>>> +			mv88e6xxx_atu_vtu_stats_strings[i],
>>> +			ETH_GSTRING_LEN);
>>> +}
>>> +
>>>  static void mv88e6xxx_get_strings(struct dsa_switch *ds, int port,
>>>  				  uint8_t *data)
>>>  {
>>> @@ -736,9 +754,12 @@ static void mv88e6xxx_get_strings(struct dsa_switch *ds, int port,
>>>  
>>>  	if (chip->info->ops->serdes_get_strings) {
>>>  		data += count * ETH_GSTRING_LEN;
>>> -		chip->info->ops->serdes_get_strings(chip, port, data);
>>> +		count = chip->info->ops->serdes_get_strings(chip, port, data);
>>>  	}
>>>  
>>> +	data += count * ETH_GSTRING_LEN;
>>> +	mv88e6xxx_atu_vtu_get_strings(data);
>>> +
>>>  	mutex_unlock(&chip->reg_lock);
>>>  }
>>>  
>>> @@ -783,10 +804,13 @@ static int mv88e6xxx_get_sset_count(struct dsa_switch *ds, int port)
>>>  	if (chip->info->ops->serdes_get_sset_count)
>>>  		serdes_count = chip->info->ops->serdes_get_sset_count(chip,
>>>  								      port);
>>> -	if (serdes_count < 0)
>>> +	if (serdes_count < 0) {
>>>  		count = serdes_count;
>>> -	else
>>> -		count += serdes_count;
>>> +		goto out;
>>> +	}
>>> +	count += serdes_count;
>>> +	count += ARRAY_SIZE(mv88e6xxx_atu_vtu_stats_strings);
>>> +
>>>  out:
>>>  	mutex_unlock(&chip->reg_lock);
>>>  
>>> @@ -841,6 +865,16 @@ static int mv88e6390_stats_get_stats(struct mv88e6xxx_chip *chip, int port,
>>>  					 0);
>>>  }
>>>  
>>> +static void mv88e6xxx_atu_vtu_get_stats(struct mv88e6xxx_chip *chip, int port,
>>> +					uint64_t *data)
>>> +{
>>> +	*data++ = chip->ports[port].atu_member_violation;
>>> +	*data++ = chip->ports[port].atu_miss_violation;
>>> +	*data++ = chip->ports[port].atu_full_violation;
>>> +	*data++ = chip->ports[port].vtu_member_violation;
>>> +	*data++ = chip->ports[port].vtu_miss_violation;
>>
>> This looks fine, but I suppose you could just have an u64 pointer which
>> is initialized to point to atu_member_violation, and then just do
>> pointer arithmetics to iterate, this would avoid possibly missing that
>> function in case new ATU/VTU violations are handled in the future?
> 
> KISS. This works and is obvious.

Fair enough.
-- 
Florian