Re: [PATCH] pid: sys_wait... fixes (v2)

[Oleg Nesterov]

On 12/06, Eric W. Biederman wrote:
> 
> +static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
> +{
> +	struct pid *pid = NULL;
> +	if (type == PIDTYPE_PID)
> +		pid = task->pids[type].pid;
> +	else if (type < PIDTYPE_MAX)
> +		pid = task->group_leader->pids[type].pid;
> +	return pid;
> +}

Looks like a useful helper regardless.

> +static int eligible_child(enum pid_type type, struct pid *pid, int options,
> +			  struct task_struct *p)
>  {
>  	int err;
> -	struct pid_namespace *ns;
>  
> -	ns = current->nsproxy->pid_ns;
> -	if (pid > 0) {
> -		if (task_pid_nr_ns(p, ns) != pid)
> -			return 0;
> -	} else if (!pid) {
> -		if (task_pgrp_nr_ns(p, ns) != task_pgrp_vnr(current))
> -			return 0;
> -	} else if (pid != -1) {
> -		if (task_pgrp_nr_ns(p, ns) != -pid)
> +	if (type < PIDTYPE_MAX) {
> +		if (task_pid_type(p, type) != pid)
>  			return 0;
>  	}

Minor, minor nit.

If type == PIDTYPE_MAX, pid must be == NULL. but task_pid_type(PIDTYPE_PID)
also returns NULL. So we can just do

	if (task_pid_type(p, type) != pid)
		return 0;

Not that it really makes a difference though.

Oleg.

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