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[Qemu-devel] [PATCH for-2.0 2/2] dataplane: replace iothread object_add(
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH for-2.0 2/2] dataplane: replace iothread object_add() with embedded instance |
Date: |
Thu, 20 Mar 2014 15:06:32 +0100 |
Before IOThread was its own object, each virtio-blk device would create
its own internal thread. We need to preserve this behavior for
backwards compatibility when users do not specify -device
virtio-blk-pci,iothread=<id>.
This patch changes how the internal IOThread object is created.
Previously we used the monitor object_add() function, which is really a
layering violation. The problem is that this needs to assign a name but
we don't have a name for this internal object.
Generating names for internal objects is a pain but even worse is that
they may collide with user-defined names.
Paolo Bonzini <address@hidden> suggested that the internal IOThread
object should not be named. This way the conflict cannot happen and we
no longer need object_add().
One gotcha is that internal IOThread objects will not be listed by the
query-iothreads command since they are not named. This is okay though
because query-iothreads is new and the internal IOThread is just for
backwards compatibility. New users should explicitly define IOThread
objects.
Reported-by: Christian Borntraeger <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/block/dataplane/virtio-blk.c | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index f558b45..70b8a5a 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -23,7 +23,7 @@
#include "virtio-blk.h"
#include "block/aio.h"
#include "hw/virtio/virtio-bus.h"
-#include "monitor/monitor.h" /* for object_add() */
+#include "qom/object_interfaces.h"
enum {
SEG_MAX = 126, /* maximum number of I/O segments */
@@ -59,7 +59,7 @@ struct VirtIOBlockDataPlane {
* use it).
*/
IOThread *iothread;
- bool internal_iothread;
+ IOThread internal_iothread_obj;
AioContext *ctx;
EventNotifier io_notifier; /* Linux AIO completion */
EventNotifier host_notifier; /* doorbell */
@@ -391,23 +391,19 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev,
VirtIOBlkConf *blk,
s->blk = blk;
if (blk->iothread) {
- s->internal_iothread = false;
s->iothread = blk->iothread;
+ object_ref(OBJECT(s->iothread));
} else {
- /* Create per-device IOThread if none specified */
- Error *local_err = NULL;
-
- s->internal_iothread = true;
- object_add(TYPE_IOTHREAD, vdev->name, NULL, NULL, &local_err);
- if (error_is_set(&local_err)) {
- error_propagate(errp, local_err);
- g_free(s);
- return;
- }
- s->iothread = iothread_find(vdev->name);
- assert(s->iothread);
+ /* Create per-device IOThread if none specified. This is for
+ * x-data-plane option compatibility. If x-data-plane is removed we
+ * can drop this.
+ */
+ object_initialize(&s->internal_iothread_obj,
+ sizeof(s->internal_iothread_obj),
+ TYPE_IOTHREAD);
+ user_creatable_complete(OBJECT(&s->internal_iothread_obj),
&error_abort);
+ s->iothread = &s->internal_iothread_obj;
}
- object_ref(OBJECT(s->iothread));
s->ctx = iothread_get_aio_context(s->iothread);
/* Prevent block operations that conflict with data plane thread */
@@ -426,9 +422,6 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
virtio_blk_data_plane_stop(s);
bdrv_set_in_use(s->blk->conf.bs, 0);
object_unref(OBJECT(s->iothread));
- if (s->internal_iothread) {
- object_unparent(OBJECT(s->iothread));
- }
g_free(s);
}
--
1.8.5.3