Re: [PATCH v2 1/7] eal: add queue macro extensions from FreeBSD

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Mar 13, 2025 at 09:00:09AM +0100, Morten Brørup wrote:
> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > Sent: Thursday, 13 March 2025 00.02
> > 
> > On Wed, 19 Feb 2025 15:55:17 +0100
> > Thomas Monjalon <thomas@monjalon.net> wrote:
> > 
> > > 14/02/2025 18:20, Stephen Hemminger:
> > > > The Linux version of sys/queue.h is frozen at an older version
> > > > and is missing the _SAFE macro variants. Several drivers started
> > > > introducing the own workarounds for this. Should be handled in EAL.
> > > >
> > > > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> > >
> > > We may want to unify with lib/eal/windows/include/sys/queue.h
> > >
> > >
> > 
> > Not sure, we have several options here:
> >   1. Keep using Linux sys/queue.h and add enhancements in rte_queue.h
> >   2. Make rte_queue.h a copy of FreeBSD version of queue.h (that is
> > what Windows did)
> >   3. Use the bsd version of queue.h.
> >      On Debian/Ubuntu this in libbsd-dev package and referred to as
> > bsd/sys/queue.h
> > 
> > I chose #1 as simplest. But all of these could work. #3 means DPDK has
> > least new
> > code, but adds another dependency to the build.
> 
> +1 to #2:
> If Linux sys/queue.h is frozen, and is a subset of FreeBSD queue.h, #2 would consolidate all the queue macros in one file.
> That seems easier to navigate (for a developer/reviewer looking at the macro definitions/implementations) than including sys/queue.h, queue.h or lib/eal/windows/include/sys/queue.h depending on O/S, and then defining the missing macros in rte_queue.h.
> A comment at the top of the rte_queue.h file could mention that it is a copy of the FreeBSD queue.h file.
> 
> -1 to #3; it adds an unnecessary dependency.
> 
> > 
> > No matter what, should add to checkpatch to block any new files that
> > include sys/queue.h
> > directly.
> 
> +1 to this.
> 

I agree with Morten, #2 looks the best option to me too.
/Bruce