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[PATCH v2 2/4] virtio-scsi: don't lock AioContext around virtio_queue_ai
From: |
Stefan Hajnoczi |
Subject: |
[PATCH v2 2/4] virtio-scsi: don't lock AioContext around virtio_queue_aio_attach_host_notifier() |
Date: |
Mon, 4 Dec 2023 11:42:57 -0500 |
virtio_queue_aio_attach_host_notifier() does not require the AioContext
lock. Stop taking the lock and add an explicit smp_wmb() because we were
relying on the implicit barrier in the AioContext lock before.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
---
hw/scsi/virtio-scsi-dataplane.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 1e684beebe..135e23fe54 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -149,23 +149,17 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
memory_region_transaction_commit();
- /*
- * These fields are visible to the IOThread so we rely on implicit barriers
- * in aio_context_acquire() on the write side and aio_notify_accept() on
- * the read side.
- */
s->dataplane_starting = false;
s->dataplane_started = true;
+ smp_wmb(); /* paired with aio_notify_accept() */
if (s->bus.drain_count == 0) {
- aio_context_acquire(s->ctx);
virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx);
virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx);
}
- aio_context_release(s->ctx);
}
return 0;
--
2.43.0