mmap man page:
"On success, mmap() returns a pointer to the mapped area. On error, the
value MAP_FAILED (that is, (void *) -1) is returned, and errno  is  set
to indicate the cause of the error."

The check in postcopy_get_tmp_page is definitely wrong and should be
fixed.
Signed-off-by: NEvgeny Yakovlev <eyakovlev@virtuozzo.com>
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Amit Shah <amit.shah@redhat.com>
Message-Id: <1469785705-16670-1-git-send-email-den@openvz.org>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>