Re: [PATCH net v3] bonding: fix feature flag setting at init time

From: Jakub Kicinski <kuba@kernel.org>
To: Jarod Wilson <jarod@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Ivan Vecera <ivecera@redhat.com>,
	Jay Vosburgh <j.vosburgh@gmail.com>,
	Veaceslav Falico <vfalico@gmail.com>,
	Andy Gospodarek <andy@greyhouse.net>,
	"David S. Miller" <davem@davemloft.net>,
	Thomas Davis <tadavis@lbl.gov>, Netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net v3] bonding: fix feature flag setting at init time
Date: Fri, 4 Dec 2020 07:45:14 -0800	[thread overview]
Message-ID: <20201204074514.6a249076@kicinski-fedora-pc1c0hjn.DHCP.thefacebook.com> (raw)
In-Reply-To: <CAKfmpSd7JH4Y--z=8iPxekzSeAr0AVmQFPHaOYX71dcRoJouXQ@mail.gmail.com>

On Thu, 3 Dec 2020 22:14:12 -0500 Jarod Wilson wrote:
> On Thu, Dec 3, 2020 at 11:50 AM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Wed,  2 Dec 2020 19:43:57 -0500 Jarod Wilson wrote:  
> > >       bond_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL | NETIF_F_GSO_UDP_L4;
> > > -#ifdef CONFIG_XFRM_OFFLOAD
> > > -     bond_dev->hw_features |= BOND_XFRM_FEATURES;
> > > -#endif /* CONFIG_XFRM_OFFLOAD */
> > >       bond_dev->features |= bond_dev->hw_features;
> > >       bond_dev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
> > >  #ifdef CONFIG_XFRM_OFFLOAD
> > > -     /* Disable XFRM features if this isn't an active-backup config */
> > > -     if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)
> > > -             bond_dev->features &= ~BOND_XFRM_FEATURES;
> > > +     bond_dev->hw_features |= BOND_XFRM_FEATURES;
> > > +     /* Only enable XFRM features if this is an active-backup config */
> > > +     if (BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP)
> > > +             bond_dev->features |= BOND_XFRM_FEATURES;
> > >  #endif /* CONFIG_XFRM_OFFLOAD */  
> >
> > This makes no functional change, or am I reading it wrong?  
> 
> You are correct, there's ultimately no functional change there, it
> primarily just condenses the code down to a single #ifdef block, and
> doesn't add and then remove BOND_XFRM_FEATURES from
> bond_dev->features, instead omitting it initially and only adding it
> when in AB mode. I'd poked at the code in that area while trying to
> get to the bottom of this, thought it made it more understandable, so
> I left it in, but ultimately, it's not necessary to fix the problem
> here.

Makes sense, but please split it out and send separately to net-next.