[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 04/10] device_core: use drain_call_rcu in in hmp_device_del/qmp_d
From: |
Paolo Bonzini |
Subject: |
[PATCH 04/10] device_core: use drain_call_rcu in in hmp_device_del/qmp_device_add |
Date: |
Fri, 25 Sep 2020 13:25:58 -0400 |
From: Maxim Levitsky <mlevitsk@redhat.com>
Soon, a device removal might only happen on RCU callback execution,
but to avoid chanding HMP semantics, just drain all pending RCU
callbacks
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Suggested-by: Stefan Hajnoczi <stefanha@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200913160259.32145-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
qdev-monitor.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/qdev-monitor.c b/qdev-monitor.c
index e9b7228480..c66ba13780 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -803,6 +803,18 @@ void qmp_device_add(QDict *qdict, QObject **ret_data,
Error **errp)
return;
}
dev = qdev_device_add(opts, errp);
+
+ /*
+ * Drain all pending RCU callbacks. This is done because
+ * some bus related operations can delay a device removal
+ * (in this case this can happen if device is added and then
+ * removed due to a configuration error)
+ * to a RCU callback, but user might expect that this interface
+ * will finish its job completely once qmp command returns result
+ * to the user
+ */
+ drain_call_rcu();
+
if (!dev) {
qemu_opts_del(opts);
return;
@@ -894,6 +906,16 @@ void qmp_device_del(const char *id, Error **errp)
}
qdev_unplug(dev, errp);
+
+ /*
+ * Drain all pending RCU callbacks. This is done because
+ * some bus related operations can delay a device removal
+ * to a RCU callback, but user might expect that this interface
+ * will finish its job completely once qmp command returns result
+ * to the user
+ */
+
+ drain_call_rcu();
}
}
--
2.26.2
[PATCH 04/10] device_core: use drain_call_rcu in in hmp_device_del/qmp_device_add,
Paolo Bonzini <=
[PATCH 09/10] virtio-scsi: use scsi_device_get, Paolo Bonzini, 2020/09/25
[PATCH 10/10] scsi/scsi_bus: fix races in REPORT LUNS, Paolo Bonzini, 2020/09/25
[PATCH 03/10] scsi/scsi_bus: switch search direction in scsi_device_find, Paolo Bonzini, 2020/09/25
Re: [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread, no-reply, 2020/09/25
Re: [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread, no-reply, 2020/09/25
Re: [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread, no-reply, 2020/09/25
Re: [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread, no-reply, 2020/09/25
Re: [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread, no-reply, 2020/09/25