netdev - Re: [net-next 06/12] i40e/ixgbe/igb: fail on new WoL flag setting WAKE

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Date:   Thu, 8 Nov 2018 07:42:50 +0100
From:   Michal Kubecek <mkubecek@...e.cz>
To:     Kevin Easton <kevin@...rana.org>
Cc:     Jeff Kirsher <jeffrey.t.kirsher@...el.com>, davem@...emloft.net,
        Todd Fujinaka <todd.fujinaka@...el.com>,
        netdev@...r.kernel.org, nhorman@...hat.com, sassmann@...hat.com
Subject: Re: [net-next 06/12] i40e/ixgbe/igb: fail on new WoL flag setting
 WAKE_MAGICSECURE

On Thu, Nov 08, 2018 at 06:05:26AM +0000, Kevin Easton wrote:
> On Wed, Nov 07, 2018 at 02:48:24PM -0800, Jeff Kirsher wrote:
> > From: Todd Fujinaka <todd.fujinaka@...el.com>
> > 
> > There's a new flag for setting WoL filters that is only
> > enabled on one manufacturer's NICs, and it's not ours. Fail
> > with EOPNOTSUPP.
> > 
> > Signed-off-by: Todd Fujinaka <todd.fujinaka@...el.com>
> > Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
> > Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
> > ---
> >  drivers/net/ethernet/intel/i40e/i40e_ethtool.c   | 3 ++-
> >  drivers/net/ethernet/intel/igb/igb_ethtool.c     | 2 +-
> >  drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 3 ++-
> >  3 files changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > index 9f8464f80783..9c1211ad2c6b 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > @@ -2377,7 +2377,8 @@ static int i40e_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
> >  		return -EOPNOTSUPP;
> >  
> >  	/* only magic packet is supported */
> > -	if (wol->wolopts && (wol->wolopts != WAKE_MAGIC))
> > +	if (wol->wolopts && (wol->wolopts != WAKE_MAGIC)
> > +			  | (wol->wolopts != WAKE_FILTER))
> >  		return -EOPNOTSUPP;
> 
> This doesn't look right.  WAKE_MAGIC and WAKE_FILTER are distinct, so
> 
> (wol->wolopts != WAKE_MAGIC) | (wol->wolopts != WAKE_FILTER)
> 
> will always be 1.

Right. Also, using "|" with logical values is rather confusing. While
the result works as expected, its priority is higher than priority of
&& (which would not be true for ||), making the code counterintuitive.

BtW, the patch subject is also wrong, the newly added flag it is dealing
with is WAKE_FILTER, not WAKE_MAGICSECURE.

> It looks like the existing test in this driver was fine - it *only*
> accepted wol->wolopts of either 0 or WAKE_MAGIC, it was already
> rejecting everything else including WAKE_FILTER.

Another way to write the check would be

	if (wol->wolopts & ~WAKE_MAGIC)

> > diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > index 5acf3b743876..c57671068245 100644
> > --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > @@ -2113,7 +2113,7 @@ static int igb_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
> >  {
> >  	struct igb_adapter *adapter = netdev_priv(netdev);
> >  
> > -	if (wol->wolopts & (WAKE_ARP | WAKE_MAGICSECURE))
> > +	if (wol->wolopts & (WAKE_ARP | WAKE_MAGICSECURE | WAKE_FILTER))
> >  		return -EOPNOTSUPP;
> >  
> >  	if (!(adapter->flags & IGB_FLAG_WOL_SUPPORTED))

I would also suggest taking the opposite approach here, i.e. listing the
flags which _are_ supported so that we don't have to update the code if
another wol flag is added (or userspace sends an invalid one):

#define SUPPORTED_WOL_MODES \
	(WAKE_PHY | WAKE_UCAST | WAKE_MCAST | WAKE_BCAST | WAKE_MAGIC)
...
	if (wol->wolopts & ~SUPPORTED_WOL_MODES)
		return -EOPNOTSUPP;


> > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> > index 732b1e6ecc43..acba067cc15a 100644
> > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> > @@ -2206,7 +2206,8 @@ static int ixgbe_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
> >  {
> >  	struct ixgbe_adapter *adapter = netdev_priv(netdev);
> >  
> > -	if (wol->wolopts & (WAKE_PHY | WAKE_ARP | WAKE_MAGICSECURE))
> > +	if (wol->wolopts & (WAKE_PHY | WAKE_ARP | WAKE_MAGICSECURE |
> > +			    WAKE_FILTER))
> >  		return -EOPNOTSUPP;
> >  
> >  	if (ixgbe_wol_exclusion(adapter, wol))

...and here.

Michal Kubecek