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Subject: Re: [PATCH 3/2] fcntl: F_[SG]ETOWN_TID
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Oleg Nesterov <oleg@redhat.com>
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Date: Mon, 03 Aug 2009 20:36:59 +0200
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On Mon, 2009-08-03 at 20:06 +0200, Oleg Nesterov wrote:
> 
> As for F_XXXOWN/F_XXXWOWN_TID interaction. Another option, perhaps, is add
> F_{SET,GET}OWN_EX which accepts a use-visible
> 
>         struct f_setown_struct {
>                 int pid;                // > 0
>                 int type;               // enumerates PIDTYPE_PID, PIDTYPE_PGID, F_PIDTYPE_THREAD
>         }
> 
> pointer via arg. Instead of F_XXXOWN_TID + int who.
> 
> This way at least the users of new api can't be confused.

This would expose PIDTYPE* to userspace, and also fixes the value of
F_PIDTYPE_THREAD.

I'm not sure we want to go there (unless of course, PIDTYPE_* is already
exposed somewhere).