Re: [PATCH net-next] ethtool: ioctl: improve error checking for set_wol

[Justin Chen <justin.chen@broadcom.com>]

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On 6/1/23 9:22 AM, Justin Chen wrote:
> 
> 
> On 6/1/2023 8:55 AM, Simon Horman wrote:
>> + Daniil Tatianin <d-tatianin@yandex-team.ru>, Andrew Lunn 
>> <andrew@lunn.ch>
>>    as per ./scripts/get_maintainer.pl --git-min-percent 25 
>> net/ethtool/ioctl.c
>>
>> On Wed, May 31, 2023 at 01:53:49PM -0700, Justin Chen wrote:
>>> The netlink version of set_wol checks for not supported wolopts and 
>>> avoids
>>> setting wol when the correct wolopt is already set. If we do the same 
>>> with
>>> the ioctl version then we can remove these checks from the driver layer.
>>
>> Hi Justin,
>>
>> Are you planning follow-up patches for the driver layer?
>>
> 
> I was planning to for the Broadcom drivers since those I can test. But I 
> could do it across the board if that is preferred.
> 
>>> Signed-off-by: Justin Chen <justin.chen@broadcom.com>
>>> ---
>>>   net/ethtool/ioctl.c | 14 ++++++++++++--
>>>   1 file changed, 12 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
>>> index 6bb778e10461..80f456f83db0 100644
>>> --- a/net/ethtool/ioctl.c
>>> +++ b/net/ethtool/ioctl.c
>>> @@ -1436,15 +1436,25 @@ static int ethtool_get_wol(struct net_device 
>>> *dev, char __user *useraddr)
>>>   static int ethtool_set_wol(struct net_device *dev, char __user 
>>> *useraddr)
>>>   {
>>> -    struct ethtool_wolinfo wol;
>>> +    struct ethtool_wolinfo wol, cur_wol;
>>>       int ret;
>>> -    if (!dev->ethtool_ops->set_wol)
>>> +    if (!dev->ethtool_ops->get_wol || !dev->ethtool_ops->set_wol)
>>>           return -EOPNOTSUPP;
>>
>> Are there cases where (in-tree) drivers provide set_wol byt not get_wol?
>> If so, does this break their set_wol support?
>>
> 
> My original thought was to match netlink set wol behavior. So drivers 
> that do that won't work with netlink set_wol right now. I'll skim around 
> to see if any drivers do this. But I would reckon this should be a 
> driver fix.
> 
> Thanks,
> Justin
> 

I see a driver at drivers/net/phy/microchip.c. But this is a phy driver 
set_wol hook.

Justin

>>> +    memset(&cur_wol, 0, sizeof(struct ethtool_wolinfo));
>>> +    cur_wol.cmd = ETHTOOL_GWOL;
>>> +    dev->ethtool_ops->get_wol(dev, &cur_wol);
>>> +
>>>       if (copy_from_user(&wol, useraddr, sizeof(wol)))
>>>           return -EFAULT;
>>> +    if (wol.wolopts & ~cur_wol.supported)
>>> +        return -EOPNOTSUPP;
>>> +
>>> +    if (wol.wolopts == cur_wol.wolopts)
>>> +        return 0;
>>> +
>>>       ret = dev->ethtool_ops->set_wol(dev, &wol);
>>>       if (ret)
>>>           return ret;

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