Mailing List Archive

From: Sergio Lopez <slp@redhat.com>

The documentation for bdrv_set_aio_context_ignore() states this:

* The caller must own the AioContext lock for the old AioContext of bs, but it
* must not own the AioContext lock for new_context (unless new_context is the
* same as the current context of bs).

As blk_set_aio_context() makes use of this function, this rule also
applies to it.

Fix all occurrences where this rule wasn't honored.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Sergio Lopez <slp@redhat.com>
Message-Id: <20201214170519.223781-2-slp@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
hw/block/dataplane/virtio-blk.c | 4 ++++
hw/block/dataplane/xen-block.c | 7 ++++++-
hw/scsi/virtio-scsi.c | 6 ++++--
3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 37499c556482..e9050c8987e7 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -172,6 +172,7 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
VirtIOBlockDataPlane *s = vblk->dataplane;
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vblk)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+ AioContext *old_context;
unsigned i;
unsigned nvqs = s->conf->num_queues;
Error *local_err = NULL;
@@ -214,7 +215,10 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
vblk->dataplane_started = true;
trace_virtio_blk_data_plane_start(s);

+ old_context = blk_get_aio_context(s->conf->conf.blk);
+ aio_context_acquire(old_context);
r = blk_set_aio_context(s->conf->conf.blk, s->ctx, &local_err);
+ aio_context_release(old_context);
if (r < 0) {
error_report_err(local_err);
goto fail_guest_notifiers;
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 71c337c7b7e7..3675f8deaf9d 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -725,6 +725,7 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
{
ERRP_GUARD();
XenDevice *xendev = dataplane->xendev;
+ AioContext *old_context;
unsigned int ring_size;
unsigned int i;

@@ -808,10 +809,14 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
goto stop;
}

- aio_context_acquire(dataplane->ctx);
+ old_context = blk_get_aio_context(dataplane->blk);
+ aio_context_acquire(old_context);
/* If other users keep the BlockBackend in the iothread, that's ok */
blk_set_aio_context(dataplane->blk, dataplane->ctx, NULL);
+ aio_context_release(old_context);
+
/* Only reason for failure is a NULL channel */
+ aio_context_acquire(dataplane->ctx);
xen_device_set_event_channel_context(xendev, dataplane->event_channel,
dataplane->ctx, &error_abort);
aio_context_release(dataplane->ctx);
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 9690bc63c860..99ff261cead1 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -849,15 +849,17 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
SCSIDevice *sd = SCSI_DEVICE(dev);
+ AioContext *old_context;
int ret;

if (s->ctx && !s->dataplane_fenced) {
if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
return;
}
- virtio_scsi_acquire(s);
+ old_context = blk_get_aio_context(sd->conf.blk);
+ aio_context_acquire(old_context);
ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
- virtio_scsi_release(s);
+ aio_context_release(old_context);
if (ret < 0) {
return;
}
--
2.30.0