Re: [PATCH] autofs: fix the wrong usage of the deprecated task_pgrp_nr()

["Serge E. Hallyn" <serue@us.ibm.com>]

Quoting Oleg Nesterov (oleg@redhat.com):
> On 01/19, Serge E. Hallyn wrote:
> >
> > Quoting Oleg Nesterov (oleg@redhat.com):
> > > On 01/19, Serge E. Hallyn wrote:
> > > >
> > > > But so there does still need to be a patch modifying parse_options()
> > > > to return an error if pgrp= was not specified, right?
> > >
> > > Why? In that case we should use the caller's pgrp. This is what the
> > > current tries to do, why should the patch change this behaviour?
> >
> > Well, because Ian said that not specifying it is supposed to
> > be an error :)  I didn't quite understand why, so am fishing
> > for more info...
> 
> I think you misunderstood him. Or I am totally confused ;)
> 
> In any case. Both autofs and autofs4 use current's pgrp if this
> option was not specified, and these patches doesn't change this
> behaviour.
> 
> 
> Actually, I am very much surprized this one-liner patch has so
> many questions. Isn't it "obiously correct" ?

I'm not sure which one-liner you're talking about.  In fact,
the patch I'm looking at right now isn't the one i looked at
before my last response.  Dangit.

The patch turning the cached pid_t into a struct pid is
certainly mostly right.  It shouldn't store a pid_t.

But as for passing pid_t's in from userspace and especially
printing them out in error messages, I believe what Ian was
trying to do before, which seemed sensible, was to always
use values in the init_pid_ns.  After all, if you do a DPRINTK
with pid_vnr(somepid), then by the time a human reads the logs
the subjective pidns might no longer exist.  So for logs I'd
tend to agree with printing out the pid_t in the init_pid_ns.

-serge