[PATCH 11/12] pid: rewrite task helper functions avoiding task->pid and task->tgid

[Peter Zijlstra]

On Tue, Aug 20, 2013 at 05:32:03PM -0400, Richard Guy Briggs wrote:
> This stops these four task helper functions from using the deprecated and
> error-prone task->pid and task->tgid.
> 
> (informed by ebiederman's ea5a4d01)
> Cc: "Eric W. Biederman" <ebiederm at xmission.com>
> Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
> ---
>  include/linux/sched.h |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 8e69807..46e739d 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1579,7 +1579,7 @@ static inline int pid_alive(struct task_struct *p)
>   */
>  static inline int is_global_init(struct task_struct *tsk)
>  {
> -	return tsk->pid == 1;
> +	return task_pid_nr(tsk) == 1;
>  }
>  
>  extern struct pid *cad_pid;
> @@ -1930,7 +1930,7 @@ extern struct task_struct *idle_task(int cpu);
>   */
>  static inline bool is_idle_task(const struct task_struct *p)
>  {
> -	return p->pid == 0;
> +	return task_pid(p) == &init_struct_pid;
>  }
>  extern struct task_struct *curr_task(int cpu);
>  extern void set_curr_task(int cpu, struct task_struct *p);

Why would you ever want to do this? It just makes these tests more
expensive for no gain what so ff'ing ever.