Re: [PATCH bpf] bpf: fix unused-var without NETDEVICES

[Matthieu Baerts]

Hi Alexei,

On 03/06/2020 20:14, Alexei Starovoitov wrote:
> On Wed, Jun 03, 2020 at 11:12:01AM +0200, Matthieu Baerts wrote:
> > Hi Ferenc,
> >
> > On 03/06/2020 10:56, Ferenc Fejes wrote:
> > > Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx> ezt Ãrta (idÅpont:
> > > 2020. jÃn. 3., Sze, 10:11):
> > > > A recent commit added new variables only used if CONFIG_NETDEVICES is
> > > > set.
> > >
> > > Thank you for noticing and fixed this!
> > >
> > > > A simple fix is to only declare these variables if the same
> > > > condition is valid.
> > > >
> > > > Other solutions could be to move the code related to SO_BINDTODEVICE
> > > > option from _bpf_setsockopt() function to a dedicated one or only
> > > > declare these variables in the related "case" section.
> > >
> > > Yes thats indeed a cleaner way to approach this. I will prepare a fix for that.
> >
> > I should have maybe added that I didn't take this approach because in the
> > rest of the code, I don't see that variables are declared only in a "case"
> > section (no "{" ... "}" after "case") and code is generally not moved into a
> > dedicated function in these big switch/cases. But maybe it makes sense here
> > because of the #ifdef!
> > At the end, I took the simple approach because it is for -net.
> >
> > In other words, I don't know what maintainers would prefer here but I am
> > happy to see any another solutions implemented to remove these compiler
> > warnings :)
>
> since CONFIG_NETDEVICES doesn't change anything in .h
> I think the best is to remove #ifdef CONFIG_NETDEVICES from net/core/filter.c
> and rely on sock_bindtoindex() returning ENOPROTOOPT
> in the extreme case of oddly configured kernels.

Good idea, thank you!
I can send a patch implementing that.

And sorry for the oddly configured kernels :)
It's just used to test the compilation of the code related to MPTCP.

Cheers,
Matt
--
Matthieu Baerts | R&D Engineer
matthieu.baerts@xxxxxxxxxxxx
Tessares SA | Hybrid Access Solutions
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