Unlike kqueue/kevent of BSD, the epoll of Linux could be
add/del by using different API on the fly.
This patch drops the notify used by mevent_add/del and
call epoll_ctl to add/delete target fd. Only keeps
global_head to track mevent added and makes the code
logic in mevent_dispatch() a littel bit simpler.
Another thing is related with epoll_ctl. If the target
fd is regular fd which doesn't support epoll, epoll_ctl
will return -1. When DM is start by systemd, the STDIO
is not mapped to terminal, epoll_ctl on STDIO could
return -1. Which block UOS boot. We only call mevent_add
after confirm STDIO is mapped to terminal.
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
