Messages in this thread | | | Date | Fri, 2 Feb 2024 20:50:32 +0100 | From | Christian Brauner <> | Subject | Re: [PATCH 1/3] pidfd_poll: report POLLHUP when pid_task() == NULL |
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On Fri, Feb 02, 2024 at 08:05:29PM +0100, Oleg Nesterov wrote: > On 02/02, Christian Brauner wrote: > > > > > I think we need a simpler patch. I was going to send it as 4/4, but I'd > > > like to think more, _perhaps_ we can also discriminate the PIDFD_THREAD > > > and non-PIDFD_THREAD waiters. I'll try to make the patch(es) tomorrow or > > > > Right, I didn't go that far. > > > > > at least provided more info. > > > > > > 3 notes for now: > > > > > > 1. we can't use wake_up_poll(), it passes nr_exclusive => 1 > > > > Bah. So we need the same stuff we did for io_uring and use > > __wake_up() directly. Or we add wake_up_all_poll() and convert the other > > three callsites: > > ... > > > +#define wake_up_all_poll(x, m) \ > > + __wake_up(x, TASK_NORMAL, 0, poll_to_key(m)) > > Agreed, but I think this + s/wake_up/wake_up_all_poll/ conversions > need a separate patch.
Yeah, I know. This is just a scribbled draft.
> > > > -void do_notify_pidfd(struct task_struct *task) > > +void pidfd_wake_up_poll(struct task_struct *task, bool dead) > > { > > - struct pid *pid; > > - > > WARN_ON(task->exit_state == 0); > > - pid = task_pid(task); > > - wake_up_all(&pid->wait_pidfd); > > + WARN_ON(mask == 0); > > + wake_up_all_poll(&task_pid(task)->wait_pidfd, > > + EPOLLIN | EPOLLRDNORM | dead ? EPOLLHUP : 0); > > No... > > This is still overcomplicated and is not right.
I'm all ears.
> Christian, I'll write another email tomorrow.
Sure, there's no rush. I had not intended that this patch be used. I have another large series I need to take care of so I can't spend a lot of time on writing this anyway. I just hadn't used the keyed apis before and got curious. So don't get the impression that I intend to write this. I fully expected you to do it.
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