svn commit: r362338 - in head: share/man/man4 sys/conf sys/kern sys/netinet sys/netinet6 sys/netipsec sys/netpfil/pf

[Mark Johnston]

On Mon, Jun 22, 2020 at 11:35:38AM -0700, John Baldwin wrote:
> On 6/21/20 6:10 PM, Mark Johnston wrote:
> > On Fri, Jun 19, 2020 at 08:33:35AM -0700, John Baldwin wrote:
> >> On 6/18/20 12:32 PM, Mark Johnston wrote:
> >>> Author: markj
> >>> Date: Thu Jun 18 19:32:34 2020
> >>> New Revision: 362338
> >>> URL: https://svnweb.freebsd.org/changeset/base/362338
> >>>
> >>> Log:
> >>>   Add the SCTP_SUPPORT kernel option.
> >>>   
> >>>   This is in preparation for enabling a loadable SCTP stack.  Analogous to
> >>>   IPSEC/IPSEC_SUPPORT, the SCTP_SUPPORT kernel option must be configured
> >>>   in order to support a loadable SCTP implementation.
> >>>   
> >>>   Discussed with:	tuexen
> >>>   MFC after:	2 weeks
> >>>   Sponsored by:	The FreeBSD Foundation
> >>
> >> Do you want to add similar handling to sys/conf/config.mk that we have
> >> for IPsec?  Also, do we want to avoid building sctp.ko if it is in the
> >> kernel like we do for ipsec.ko and/or only build it if the kernel contains
> >> SCTP_SUPPORT?  (For ipsec.ko we had to do that as it wouldn't compile, not
> >> sure if the same is true for sctp.ko)
> > 
> > Sorry for the delay.
> > I think we do indeed want similar handling in config.mk, I will work on
> > it.  It is probably also reasonable to avoid compiling sctp.ko when
> > SCTP_SUPPORT is not defined, though I can't see a reason that wouldn't
> > work today since SCTP_SUPPORT is not used in any headers.
> 
> Ok.  ipsec.ko mattered more when the build broke.  Whether or not we compile
> "duplicate" modules for kernels is perhaps a larger question.  I think I
> might favor that change, but it is a larger change that merits some thought.
> In particular, you want good code coverage for things like LINT builds, so
> maybe we really should still compile modules whenever possible.

I tend to assume that a buildkernel of GENERIC without any special flags
will always build all modules (except those not available for the target
platform of course), so I was a bit surprised to see that this isn't the
case for ipsec.ko.  As Rodney pointed out it provides marginally better
coverage against build breaks.  If you think we can restore the old
behaviour for ipsec without too much work I think it'd be reasonable to
change that and compile sctp.ko even when "options SCTP" is configured.
I can't spot any similar cases in sys/modules/Makefile with a bit of
skimming.