[CRIU] [PATCH v2 11/57] pid: Add equel_pid() helper

[Andrei Vagin]

On Tue, Mar 28, 2017 at 06:35:47PM +0300, Kirill Tkhai wrote:
> This allows to compare pids values on the whole hierarhy.
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  criu/include/pid.h |   17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/criu/include/pid.h b/criu/include/pid.h
> index 475b17a3..478e5d0b 100644
> --- a/criu/include/pid.h
> +++ b/criu/include/pid.h
> @@ -4,6 +4,7 @@
>  #include <compel/task-state.h>
>  #include "stdbool.h"
>  #include "rbtree.h"
> +#include "log.h"
>  
>  /*
>   * Task states, used in e.g. struct pid's state.
> @@ -45,6 +46,22 @@ struct pid {
>  	} ns[1]; /* Must be at the end of struct pid */
>  };
>  
> +#define equal_pid(a, b)							\
> +({									\
> +	int ___i, ___ret = true;					\
> +	if (a->level == b->level) {					\
> +		for (___i = 0; ___i < a->level; ___i++)			\
> +			if (a->ns[___i].virt != b->ns[___i].virt) {	\
> +				___ret = false;				\
> +				break;					\
> +			}						\
> +	} else {							\
> +		pr_err("Wrong pid nesting level\n");			\

Why do we need this message here?

> +		___ret = false;						\
> +	}								\
> +	___ret;								\
> +})
> +
>  /*
>   * When we have to restore a shared resource, we mush select which
>   * task should do it, and make other(s) wait for it. In order to
>