Confused, please help...
On 05/21, Mike Christie wrote:
>
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -338,6 +338,7 @@ static int vhost_worker(void *data)
> struct vhost_worker *worker = data;
> struct vhost_work *work, *work_next;
> struct llist_node *node;
> + bool dead = false;
>
> for (;;) {
> /* mb paired w/ kthread_stop */
> @@ -349,8 +350,22 @@ static int vhost_worker(void *data)
> }
>
> node = llist_del_all(&worker->work_list);
> - if (!node)
> + if (!node) {
> schedule();
> + /*
> + * When we get a SIGKILL our release function will
> + * be called. That will stop new IOs from being queued
> + * and check for outstanding cmd responses. It will then
> + * call vhost_task_stop to tell us to return and exit.
> + */
But who will call the release function / vhost_task_stop() and when this
will happen after this thread gets SIGKILL ?
> + if (!dead && signal_pending(current)) {
> + struct ksignal ksig;
> +
> + dead = get_signal(&ksig);
> + if (dead)
> + clear_thread_flag(TIF_SIGPENDING);
If you do clear_thread_flag(TIF_SIGPENDING), then why do we need 1/3 ?
Also. Suppose that vhost_worker() dequeues SIGKILL and clears TIF_SIGPENDING.
SIGSTOP, PTRACE_INTERRUPT, freezer can come and set TIF_SIGPENDING again.
In this case the main for (;;) loop will spin without sleeping until
vhost_task_should_stop() becomes true?
Oleg.
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