[Devel] Re: [PATCH 1/13] Round up the API

[Pavel Emelianov]

Eric W. Biederman wrote:
> "Serge E. Hallyn" <serue at us.ibm.com> writes:
> 
>> Quoting Pavel Emelianov (xemul at openvz.org):
>>> The set of functions process_session, task_session, process_group
>>> and task_pgrp is confusing, as the names can be mixed with each other
>>> when looking at the code for a long time.
>>>
>>> The proposals are to
>>> * equip the functions that return the integer with _nr suffix to
>>>   represent that fact,
>>> * and to make all functions work with task (not process) by making
>>>   the common prefix of the same name.
>>>
>>> For monotony the routines signal_session() and set_signal_session()
>>> are replaced with task_session_nr() and set_task_session(), especially
>>> since they are only used with the explicit task->signal dereference.
>>>
>>> I've sent this before, but Andrew didn't include it, so I resend it
>>> as the part of this set.
>>>
>>> Signed-off-by: Pavel Emelianov <xemul at openvz.org>
>>> Acked-by: Serge E. Hallyn <serue at us.ibm.com>
>> Yup, I still like this patch.
> 
> I'm borderline.  Less error prone interfaces sound good, less
> duplication of information sounds good.  Changing the names of
> historical function may be change for the sake of change and
> thus noise.

They are not historical. These calls appeared soon after new
struct pid subsystem.

> 
> However if we are going to go this far I think we need to remove
> the numeric pid cache from the task_struct.

Object. Numerical pid and tgid on task makes it possible (and this
is done in ia64) to export this to user faster.

Moreover there can be places in kernel when we still hold the tasks
and want to know its pid, but the task is dead already and is going
to be delayed_put_task()-ed without pids aboard. I know this can
be properly if()-ed but what for?

> Eric
>