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Tsirkin" , Maxim Levitsky , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This allows to preserve the semantics of hmp_device_del, that the device is deleted immediatly which was changed by previos patch that delayed this to RCU callback Suggested-by: Stefan Hajnoczi Signed-off-by: Maxim Levitsky Reviewed-by: Stefan Hajnoczi --- include/qemu/rcu.h | 1 + qdev-monitor.c | 3 +++ util/rcu.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 37 insertions(+) diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h index 570aa603eb..0e375ebe13 100644 --- a/include/qemu/rcu.h +++ b/include/qemu/rcu.h @@ -133,6 +133,7 @@ struct rcu_head { }; =20 extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func); +extern void drain_call_rcu(void); =20 /* The operands of the minus operator must have the same type, * which must be the one that we specify in the cast. diff --git a/qdev-monitor.c b/qdev-monitor.c index 56cee1483f..70877840a2 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -812,6 +812,8 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, E= rror **errp) return; } dev =3D qdev_device_add(opts, &local_err); + drain_call_rcu(); + if (!dev) { error_propagate(errp, local_err); qemu_opts_del(opts); @@ -904,6 +906,7 @@ void qmp_device_del(const char *id, Error **errp) } =20 qdev_unplug(dev, errp); + drain_call_rcu(); } } =20 diff --git a/util/rcu.c b/util/rcu.c index 60a37f72c3..e8b1c4d6c5 100644 --- a/util/rcu.c +++ b/util/rcu.c @@ -293,6 +293,39 @@ void call_rcu1(struct rcu_head *node, void (*func)(str= uct rcu_head *node)) qemu_event_set(&rcu_call_ready_event); } =20 + +struct rcu_drain { + struct rcu_head rcu; + QemuEvent drain_complete_event; +}; + +static void drain_rcu_callback(struct rcu_head *node) +{ + struct rcu_drain *event =3D (struct rcu_drain *)node; + qemu_event_set(&event->drain_complete_event); +} + +void drain_call_rcu(void) +{ + struct rcu_drain rcu_drain; + bool locked =3D qemu_mutex_iothread_locked(); + + memset(&rcu_drain, 0, sizeof(struct rcu_drain)); + + if (locked) { + qemu_mutex_unlock_iothread(); + } + + qemu_event_init(&rcu_drain.drain_complete_event, false); + call_rcu1(&rcu_drain.rcu, drain_rcu_callback); + qemu_event_wait(&rcu_drain.drain_complete_event); + + if (locked) { + qemu_mutex_lock_iothread(); + } + +} + void rcu_register_thread(void) { assert(rcu_reader.ctr =3D=3D 0); --=20 2.17.2