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virtio-scsi: use aio handler for data plane

Browse source 
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 <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-04-06 12:16:27 +02:00 • committed by Michael S. Tsirkin
parent 8a2fad57eb
commit a8f2e5c8ff
3 changed files with 86 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

65
hw/scsi/virtio-scsi.c
View file

@ -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)