There is a batching mechanism for virtio-blk Used Buffer Notifications
that is no longer needed because the previous commit added batching to
virtio_notify_irqfd().
Note that this mechanism was rarely used in practice because it is only
enabled when EVENT_IDX is not negotiated by the driver. Modern drivers
enable EVENT_IDX.
Signed-off-by: Stefan Hajnoczi
---
hw/block/dataplane/virtio-blk.c | 48 +
1 file changed, 1 insertion(+), 47 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index da36fcfd0b..f83bb0f116 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -31,9 +31,6 @@ struct VirtIOBlockDataPlane {
VirtIOBlkConf *conf;
VirtIODevice *vdev;
-QEMUBH *bh; /* bh for guest notification */
-unsigned long *batch_notify_vqs;
-bool batch_notifications;
/* Note that these EventNotifiers are assigned by value. This is
* fine as long as you do not call event_notifier_cleanup on them
@@ -47,36 +44,7 @@ struct VirtIOBlockDataPlane {
/* Raise an interrupt to signal guest, if necessary */
void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq)
{
-if (s->batch_notifications) {
-set_bit(virtio_get_queue_index(vq), s->batch_notify_vqs);
-qemu_bh_schedule(s->bh);
-} else {
-virtio_notify_irqfd(s->vdev, vq);
-}
-}
-
-static void notify_guest_bh(void *opaque)
-{
-VirtIOBlockDataPlane *s = opaque;
-unsigned nvqs = s->conf->num_queues;
-unsigned long bitmap[BITS_TO_LONGS(nvqs)];
-unsigned j;
-
-memcpy(bitmap, s->batch_notify_vqs, sizeof(bitmap));
-memset(s->batch_notify_vqs, 0, sizeof(bitmap));
-
-for (j = 0; j < nvqs; j += BITS_PER_LONG) {
-unsigned long bits = bitmap[j / BITS_PER_LONG];
-
-while (bits != 0) {
-unsigned i = j + ctzl(bits);
-VirtQueue *vq = virtio_get_queue(s->vdev, i);
-
-virtio_notify_irqfd(s->vdev, vq);
-
-bits &= bits - 1; /* clear right-most bit */
-}
-}
+virtio_notify_irqfd(s->vdev, vq);
}
/* Context: QEMU global mutex held */
@@ -126,9 +94,6 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev,
VirtIOBlkConf *conf,
} else {
s->ctx = qemu_get_aio_context();
}
-s->bh = aio_bh_new_guarded(s->ctx, notify_guest_bh, s,
- (vdev)->mem_reentrancy_guard);
-s->batch_notify_vqs = bitmap_new(conf->num_queues);
*dataplane = s;
@@ -146,8 +111,6 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
vblk = VIRTIO_BLK(s->vdev);
assert(!vblk->dataplane_started);
-g_free(s->batch_notify_vqs);
-qemu_bh_delete(s->bh);
if (s->iothread) {
object_unref(OBJECT(s->iothread));
}
@@ -173,12 +136,6 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
s->starting = true;
-if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
-s->batch_notifications = true;
-} else {
-s->batch_notifications = false;
-}
-
/* Set up guest notifier (irq) */
r = k->set_guest_notifiers(qbus->parent, nvqs, true);
if (r != 0) {
@@ -370,9 +327,6 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev)
aio_context_release(s->ctx);
-qemu_bh_cancel(s->bh);
-notify_guest_bh(s); /* final chance to notify guest */
-
/* Clean up guest notifier (irq) */
k->set_guest_notifiers(qbus->parent, nvqs, false);
--
2.41.0
