[PATCH] detach_pid(): restore optimization

[PATCH] detach_pid(): restore optimization

Kirill's kernel/pid.c rework broke optimization logic in detach_pid().  Non
zero return from __detach_pid() was used to indicate, that this pid can
probably be freed.  Current version always (modulo idle threads) return non
zero value, thus resulting in unneccesary pid_hash scanning.

Also, uninlining __detach_pid() reduces pid.o text size from 2492 to 1600
bytes.

Acked-By: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>