From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39918) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dvNfF-0001e1-DE for qemu-devel@nongnu.org; Fri, 22 Sep 2017 09:06:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dvNfA-0003F5-R7 for qemu-devel@nongnu.org; Fri, 22 Sep 2017 09:06:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38904) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dvNfA-0003EJ-HI for qemu-devel@nongnu.org; Fri, 22 Sep 2017 09:06:36 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A220F8A002 for ; Fri, 22 Sep 2017 13:06:35 +0000 (UTC) Date: Fri, 22 Sep 2017 21:06:26 +0800 From: Fam Zheng Message-ID: <20170922130626.GE32000@lemon> References: <1506070572-7549-1-git-send-email-peterx@redhat.com> <1506070572-7549-3-git-send-email-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1506070572-7549-3-git-send-email-peterx@redhat.com> Subject: Re: [Qemu-devel] [PATCH 2/3] iothread: export iothread_stop() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: qemu-devel@nongnu.org, "Dr . David Alan Gilbert" , Stefan Hajnoczi , Paolo Bonzini 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 > --- > 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 > >