On Fri, 04/01 15:19, Paolo Bonzini wrote:
> In addition to handling IO in vcpu thread and in io thread, dataplane
> introduces yet another mode: handling it by aio.
>
> This reuses the same handler as previous modes, which triggers races as
> these were not designed to be reentrant.
>
> Use a separate handler just for aio, and disable regular handlers when
> dataplane is active.
>
> Reviewed-by: Cornelia Huck <cornelia.h...@de.ibm.com>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> hw/scsi/virtio-scsi-dataplane.c | 43 ++++++++++++++++++++++++---
> hw/scsi/virtio-scsi.c | 65
> ++++++++++++++++++++++++++++-------------
> include/hw/virtio/virtio-scsi.h | 6 ++--
> 3 files changed, 86 insertions(+), 28 deletions(-)
>
> diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
> index 21d5bfd..a497a2c 100644
> --- a/hw/scsi/virtio-scsi-dataplane.c
> +++ b/hw/scsi/virtio-scsi-dataplane.c
> @@ -38,7 +38,35 @@ void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread
> *iothread)
> }
> }
>
> -static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n)
> +static void virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev,
> + VirtQueue *vq)
> +{
> + VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> +
> + assert(s->ctx && s->dataplane_started);
> + virtio_scsi_handle_cmd_vq(s, vq);
> +}
> +
> +static void virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev,
> + VirtQueue *vq)
> +{
> + VirtIOSCSI *s = VIRTIO_SCSI(vdev);
> +
> + assert(s->ctx && s->dataplane_started);
> + virtio_scsi_handle_ctrl_vq(s, vq);
> +}
> +
> +static void virtio_scsi_data_plane_handle_event(VirtIODevice *vdev,
> + VirtQueue *vq)
> +{
> + VirtIOSCSI *s = VIRTIO_SCSI(vdev);
> +
> + assert(s->ctx && s->dataplane_started);
> + virtio_scsi_handle_event_vq(s, vq);
> +}
> +
> +static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n,
> + void (*fn)(VirtIODevice *vdev, VirtQueue *vq))
Are tabs used by mistake? Three more occasions below...
> {
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
> VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> @@ -54,6 +82,7 @@ static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue
> *vq, int n)
> }
>
> virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true);
> + virtio_set_queue_aio(vq, fn);
> return 0;
> }
>
>
> @@ -104,16 +136,19 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
> }
>
> aio_context_acquire(s->ctx);
> - rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0);
> + rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0,
> + virtio_scsi_data_plane_handle_ctrl);
Tabs.
> if (rc) {
> goto fail_vrings;
> }
> - rc = virtio_scsi_vring_init(s, vs->event_vq, 1);
> + rc = virtio_scsi_vring_init(s, vs->event_vq, 1,
> + virtio_scsi_data_plane_handle_event);
Tabs.
> if (rc) {
> goto fail_vrings;
> }
> for (i = 0; i < vs->conf.num_queues; i++) {
> - rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2);
> + rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2,
> + virtio_scsi_data_plane_handle_cmd);
Tabs.
> if (rc) {
> goto fail_vrings;
> }
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 38f1e2c..30415c6 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -374,7 +374,7 @@ fail:
> return ret;
> }
>
> -void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
> +static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
> {
> VirtIODevice *vdev = (VirtIODevice *)s;
> uint32_t type;
> @@ -412,20 +412,28 @@ void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> }
> }
>
> -static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
> +void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
> {
> - VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> VirtIOSCSIReq *req;
>
> - if (s->ctx && !s->dataplane_started) {
> - virtio_scsi_dataplane_start(s);
> - return;
> - }
> while ((req = virtio_scsi_pop_req(s, vq))) {
> virtio_scsi_handle_ctrl_req(s, req);
> }
> }
>
> +static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
> +{
> + VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> +
> + if (s->ctx) {
> + virtio_scsi_dataplane_start(s);
> + if (!s->dataplane_fenced) {
> + return;
> + }
Could be more readable if virtio_scsi_dataplane_start has a return value
indicating success.
> + }
> + virtio_scsi_handle_ctrl_vq(s, vq);
> +}
> +
> static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
> {
> /* Sense data is not in req->resp and is copied separately
> @@ -508,7 +516,7 @@ static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
> virtio_scsi_complete_cmd_req(req);
> }
>
> -bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
> +static bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq
> *req)
Isn't this line too long now?
> {
> VirtIOSCSICommon *vs = &s->parent_obj;
> SCSIDevice *d;
> @@ -550,7 +558,7 @@ bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> return true;
> }
>
> -void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
> +static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq
> *req)
> {
> SCSIRequest *sreq = req->sreq;
> if (scsi_req_enqueue(sreq)) {
> @@ -560,17 +568,11 @@ void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> scsi_req_unref(sreq);
> }
>
> -static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
> +void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
> {
> - /* use non-QOM casts in the data path */
> - VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> VirtIOSCSIReq *req, *next;
> QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
>
> - if (s->ctx && !s->dataplane_started) {
> - virtio_scsi_dataplane_start(s);
> - return;
> - }
> while ((req = virtio_scsi_pop_req(s, vq))) {
> if (virtio_scsi_handle_cmd_req_prepare(s, req)) {
> QTAILQ_INSERT_TAIL(&reqs, req, next);
> @@ -582,6 +584,20 @@ static void virtio_scsi_handle_cmd(VirtIODevice *vdev,
> VirtQueue *vq)
> }
> }
>
> +static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
> +{
> + /* use non-QOM casts in the data path */
> + VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> +
> + if (s->ctx) {
> + virtio_scsi_dataplane_start(s);
> + if (!s->dataplane_fenced) {
> + return;
> + }
> + }
> + virtio_scsi_handle_cmd_vq(s, vq);
> +}
> +
> static void virtio_scsi_get_config(VirtIODevice *vdev,
> uint8_t *config)
> {
> @@ -725,17 +741,24 @@ out:
> }
> }
>
> +void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
> +{
> + if (s->events_dropped) {
> + virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
> + }
> +}
> +
> static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
> {
> VirtIOSCSI *s = VIRTIO_SCSI(vdev);
>
> - if (s->ctx && !s->dataplane_started) {
> + if (s->ctx) {
> virtio_scsi_dataplane_start(s);
> - return;
> - }
> - if (s->events_dropped) {
> - virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
> + if (!s->dataplane_fenced) {
> + return;
> + }
> }
> + virtio_scsi_handle_event_vq(s, vq);
> }
>
> static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense
> sense)
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index eef4e95..ba2f5ce 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -139,9 +139,9 @@ void virtio_scsi_common_realize(DeviceState *dev, Error
> **errp,
> HandleOutput cmd);
>
> void virtio_scsi_common_unrealize(DeviceState *dev, Error **errp);
> -void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req);
> -bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req);
> -void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req);
> +void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq);
> +void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq);
> +void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq);
> void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req);
> void virtio_scsi_free_req(VirtIOSCSIReq *req);
> void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
> --
> 1.8.3.1
>
>
