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Re: [Qemu-devel] [PATCH 2/3] iothread: export iothread_stop()
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] iothread: export iothread_stop() |
Date: |
Fri, 22 Sep 2017 21:06:26 +0800 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Fri, 09/22 16:56, Peter Xu wrote:
> So that internal iothread users can explicitly stop one iothread without
> destroying it.
>
> Since at it, fix iothread_stop() to allow re-entrance. Before this
I don't think there is any re-entrace here. Maybe you mean
s/re-entrance/calling multiple times/
?
> patch we may call iothread_stop() twice on single iothread, while that
> may not be correct since qemu_thread_join() is not allowed to run twice.
> From manual of pthread_join():
Is one call from iothread_stop_all() and one from object finalize?
>
> Joining with a thread that has previously been joined results in
> undefined behavior.
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
> include/sysemu/iothread.h | 1 +
> iothread.c | 24 ++++++++++++++++--------
> 2 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
> index b07663f..110329b 100644
> --- a/include/sysemu/iothread.h
> +++ b/include/sysemu/iothread.h
> @@ -52,6 +52,7 @@ GMainContext *iothread_get_g_main_context(IOThread
> *iothread);
> * "query-iothreads".
> */
> IOThread *iothread_create(const char *id, Error **errp);
> +void iothread_stop(IOThread *iothread);
> void iothread_destroy(IOThread *iothread);
>
> #endif /* IOTHREAD_H */
> diff --git a/iothread.c b/iothread.c
> index 74e400c..894756b 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -80,13 +80,10 @@ static void *iothread_run(void *opaque)
> return NULL;
> }
>
> -static int iothread_stop(Object *object, void *opaque)
> +void iothread_stop(IOThread *iothread)
> {
> - IOThread *iothread;
> -
> - iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
> - if (!iothread || !iothread->ctx) {
> - return 0;
> + if (iothread->stopping) {
> + return;
> }
> iothread->stopping = true;
> aio_notify(iothread->ctx);
> @@ -94,6 +91,17 @@ static int iothread_stop(Object *object, void *opaque)
> g_main_loop_quit(iothread->main_loop);
> }
> qemu_thread_join(&iothread->thread);
> +}
> +
> +static int iothread_stop_iter(Object *object, void *opaque)
> +{
> + IOThread *iothread;
> +
> + iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
> + if (!iothread || !iothread->ctx) {
> + return 0;
> + }
I think the check of iothread->ctx can be moved to iothread_stop() too.
Fam
> + iothread_stop(iothread);
> return 0;
> }
>
> @@ -108,7 +116,7 @@ static void iothread_instance_finalize(Object *obj)
> {
> IOThread *iothread = IOTHREAD(obj);
>
> - iothread_stop(obj, NULL);
> + iothread_stop(iothread);
> qemu_cond_destroy(&iothread->init_done_cond);
> qemu_mutex_destroy(&iothread->init_done_lock);
> if (!iothread->ctx) {
> @@ -328,7 +336,7 @@ void iothread_stop_all(void)
> aio_context_release(ctx);
> }
>
> - object_child_foreach(container, iothread_stop, NULL);
> + object_child_foreach(container, iothread_stop_iter, NULL);
> }
>
> static gpointer iothread_g_main_context_init(gpointer opaque)
> --
> 2.7.4
>
>
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, (continued)
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Stefan Hajnoczi, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Paolo Bonzini, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Daniel P. Berrange, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Paolo Bonzini, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Daniel P. Berrange, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Stefan Hajnoczi, 2017/09/22
- Re: [Qemu-devel] [PATCH 1/3] iothread: provide helpers for internal use, Daniel P. Berrange, 2017/09/22
[Qemu-devel] [PATCH 2/3] iothread: export iothread_stop(), Peter Xu, 2017/09/22
- Re: [Qemu-devel] [PATCH 2/3] iothread: export iothread_stop(),
Fam Zheng <=
[Qemu-devel] [PATCH 3/3] iothread: delay the context release to finalize, Peter Xu, 2017/09/22