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[Qemu-devel] [PATCH 6/7] virtio-scsi: use aio handler for data plane
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 6/7] virtio-scsi: use aio handler for data plane |
Date: |
Wed, 6 Apr 2016 12:16:27 +0200 |
In addition to handling IO in vcpu thread and in io thread, dataplane
introduces yet another mode: handling it by AioContext.
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 <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
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 b44ac5d..39ad086 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))
{
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;
}
@@ -71,9 +100,12 @@ static void virtio_scsi_clear_aio(VirtIOSCSI *s)
int i;
virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false,
false);
+ virtio_set_queue_aio(vs->ctrl_vq, NULL);
virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false,
false);
+ virtio_set_queue_aio(vs->event_vq, NULL);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx,
false, false);
+ virtio_set_queue_aio(vs->cmd_vqs[i], NULL);
}
}
@@ -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);
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);
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);
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;
+ }
+ }
+ 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)
{
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
- [Qemu-devel] [PATCH v3 0/7] virtio: aio handler API, Paolo Bonzini, 2016/04/06
- [Qemu-devel] [PATCH 3/7] virtio-scsi: fix disabled mode, Paolo Bonzini, 2016/04/06
- [Qemu-devel] [PATCH 6/7] virtio-scsi: use aio handler for data plane,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 1/7] virtio: make virtio_queue_notify_vq static, Paolo Bonzini, 2016/04/06
- [Qemu-devel] [PATCH 5/7] virtio-blk: use aio handler for data plane, Paolo Bonzini, 2016/04/06
- [Qemu-devel] [PATCH 7/7] virtio: merge virtio_queue_aio_set_host_notifier_handler with virtio_queue_set_aio, Paolo Bonzini, 2016/04/06
- Re: [Qemu-devel] [PATCH v3 0/7] virtio: aio handler API, Cornelia Huck, 2016/04/06
- Re: [Qemu-devel] [PATCH v3 0/7] virtio: aio handler API, Christian Borntraeger, 2016/04/07
- Re: [Qemu-devel] [PATCH v3 0/7] virtio: aio handler API, Christian Borntraeger, 2016/04/07