Re: [PATCH bug-fix] iproute: fix documentation for ip rule scan order

[Phil Sutter <phil@nwl.cc>]

On Thu, Sep 08, 2016 at 01:48:08PM +0200, Michal Kubecek wrote:
> On Thu, Sep 08, 2016 at 12:33:03PM +0200, Phil Sutter wrote:
> > On Thu, Sep 08, 2016 at 11:59:55AM +0200, Michal Kubecek wrote:
> > > 
> > > I'm sorry I didn't notice before but this just reverts the change done
> > > by commit 49572501664d ("iproute2: clarification of various man8 pages").
> > > IMHO the problem is that both versions are equally confusing as the word
> > > "priority" can be understood in two different senses.
> > > 
> > > How about more explicit formulation, e.g.
> > > 
> > >   ... in order of decreasing logical priority (i.e. increasing numeric
> > >   values).
> > > 
> > > Would that be better?
> > 
> > Looks like the real issue is missing definition of priority. What about
> > this:
> > 
> > diff --git a/man/man8/ip-rule.8 b/man/man8/ip-rule.8
> > index 3508d8090fd2c..13fe9f7f892ee 100644
> > --- a/man/man8/ip-rule.8
> > +++ b/man/man8/ip-rule.8
> > @@ -93,7 +93,7 @@ Each policy routing rule consists of a
> >  .B selector
> >  and an
> >  .B action predicate.
> > -The RPDB is scanned in order of increasing priority. The selector
> > +The RPDB is scanned in order of decreasing priority. The selector
> >  of each rule is applied to {source address, destination address, incoming
> >  interface, tos, fwmark} and, if the selector matches the packet,
> >  the action is performed. The action predicate may return with success.
> > @@ -221,8 +221,10 @@ value to match.
> >  
> >  .TP
> >  .BI priority " PREFERENCE"
> > -the priority of this rule. Each rule should have an explicitly
> > -set
> > +the priority of this rule.
> > +.I PREFERENCE
> > +is an unsigned integer value, higher number means lower priority.  Each rule
> > +should have an explicitly set
> >  .I unique
> >  priority value.
> >  The options preference and order are synonyms with priority.
> 
> Formally, this would be certainly sufficient. But for clarity (and
> inattentive readers), I would still prefer to be more explicit in the
> first hunk, e.g.
> 
>   ... in order of decreasing priority (increasing PREFERENCE values).

I'm fine with that, though fear mentioning PREFERENCE here might confuse
readers. I'd go with "i.e. increasing numeric values" instead. But after
all this is quite a discussion for such a tiny bit of documentation. :)

Cheers, Phil