cmpxchg in 2.5.38

[Pete Zaitcev]

The cmpxchg() is used in kernel/pid.c:next_free_map():

                        if (cmpxchg(&map->page, NULL, (void *) page))
                                free_page(page);

It is implemented on alpha, i386, ia64, ppc64, ppc, sparc64,
x86_64, but not on mips, cris, arm, s390, s390x, sparc, sh, parisc.
Do all architectures have to have it?

-- Pete