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Re: [Qemu-devel] [PATCH v5 7/7] virtio-scsi: Handle TMF request cancella
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v5 7/7] virtio-scsi: Handle TMF request cancellation asynchronously |
Date: |
Tue, 30 Sep 2014 10:44:09 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 |
Il 30/09/2014 05:40, Fam Zheng ha scritto:
> For VIRTIO_SCSI_T_TMF_ABORT_TASK and VIRTIO_SCSI_T_TMF_ABORT_TASK_SET,
> use scsi_req_cancel_async to start the cancellation.
>
> Because each tmf command may cancel multiple requests, we need to use a
> counter to track the number of remaining requests we still need to wait
> for.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> hw/scsi/virtio-scsi.c | 64
> ++++++++++++++++++++++++++++++++++++-----
> include/hw/virtio/virtio-scsi.h | 10 +++++--
> 2 files changed, 65 insertions(+), 9 deletions(-)
>
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index fa36e23..c90da38 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -208,12 +208,33 @@ static void *virtio_scsi_load_request(QEMUFile *f,
> SCSIRequest *sreq)
> return req;
> }
>
> -static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
> +typedef struct {
> + Notifier notifier;
> + VirtIOSCSIReq *tmf_req;
> +} VirtIOSCSICancelNotifier;
> +
> +static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
> +{
> + VirtIOSCSICancelNotifier *n = container_of(notifier,
> + VirtIOSCSICancelNotifier,
> + notifier);
> +
> + if (--n->tmf_req->remaining == 0) {
> + virtio_scsi_complete_req(n->tmf_req);
> + }
> + g_slice_free(VirtIOSCSICancelNotifier, n);
> +}
> +
> +/* Return 0 if the request is ready to be completed and return to guest;
> + * -EINPROGRESS if the request is submitted and will be completed later, in
> the
> + * case of async cancellation. */
> +static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
> {
> SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf.lun);
> SCSIRequest *r, *next;
> BusChild *kid;
> int target;
> + int ret = 0;
>
> if (s->dataplane_started && bdrv_get_aio_context(d->conf.bs) != s->ctx) {
> aio_context_acquire(s->ctx);
> @@ -251,7 +272,14 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> */
> req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
> } else {
> - scsi_req_cancel(r);
> + VirtIOSCSICancelNotifier *notifier;
> +
> + req->remaining = 1;
> + notifier = g_slice_new(VirtIOSCSICancelNotifier);
> + notifier->tmf_req = req;
> + notifier->notifier.notify = virtio_scsi_cancel_notify;
> + scsi_req_cancel_async(r, ¬ifier->notifier);
> + ret = -EINPROGRESS;
> }
> }
> break;
> @@ -277,6 +305,13 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
> goto incorrect_lun;
> }
> +
> + /* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
> + * This way, if the bus starts calling back to the notifiers
> + * even before we finish the loop, virtio_scsi_cancel_notify
> + * will not complete the TMF too early.
> + */
> + req->remaining = 1;
> QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
> if (r->hba_private) {
> if (req->req.tmf.subtype ==
> VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
> @@ -286,10 +321,19 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> req->resp.tmf.response =
> VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
> break;
> } else {
> - scsi_req_cancel(r);
> + VirtIOSCSICancelNotifier *notifier;
> +
> + req->remaining++;
> + notifier = g_slice_new(VirtIOSCSICancelNotifier);
> + notifier->notifier.notify = virtio_scsi_cancel_notify;
> + notifier->tmf_req = req;
> + scsi_req_cancel_async(r, ¬ifier->notifier);
> }
> }
> }
> + if (--req->remaining > 0) {
> + ret = -EINPROGRESS;
> + }
> break;
>
> case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
> @@ -310,20 +354,22 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> break;
> }
>
> - return;
> + return ret;
>
> incorrect_lun:
> req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
> - return;
> + return ret;
>
> fail:
> req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
> + return ret;
> }
>
> void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
> {
> VirtIODevice *vdev = (VirtIODevice *)s;
> int type;
> + int r = 0;
>
> if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
> &type, sizeof(type)) < sizeof(type)) {
> @@ -337,7 +383,7 @@ void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
> virtio_scsi_bad_req();
> } else {
> - virtio_scsi_do_tmf(s, req);
> + r = virtio_scsi_do_tmf(s, req);
> }
>
> } else if (req->req.tmf.type == VIRTIO_SCSI_T_AN_QUERY ||
> @@ -350,7 +396,11 @@ void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> req->resp.an.response = VIRTIO_SCSI_S_OK;
> }
> }
> - virtio_scsi_complete_req(req);
> + if (r == 0) {
> + virtio_scsi_complete_req(req);
> + } else {
> + assert(r = -EINPROGRESS);
Oops. :)
Applied to scsi-next.
Paolo
> + }
> }
>
> static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index 6134c0b..d6e5e79 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -213,8 +213,14 @@ typedef struct VirtIOSCSIReq {
> VirtQueueElement elem;
> /* Set by dataplane code. */
> VirtIOSCSIVring *vring;
> - /* Used by two stages request submitting */
> - QTAILQ_ENTRY(VirtIOSCSIReq) next;
> +
> + union {
> + /* Used for two-stage request submission */
> + QTAILQ_ENTRY(VirtIOSCSIReq) next;
> +
> + /* Used for cancellation of request during TMFs */
> + int remaining;
> + };
>
> SCSIRequest *sreq;
> size_t resp_size;
>
- [Qemu-devel] [PATCH v5 0/7] virtio-scsi: Asynchronous cancellation, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 1/7] scsi: Drop scsi_req_abort, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 2/7] scsi-generic: Handle canceled request in scsi_command_complete, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 3/7] scsi-bus: Unify request unref in scsi_req_cancel, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 4/7] scsi: Drop SCSIReqOps.cancel_io, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 5/7] scsi: Introduce scsi_req_cancel_complete, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 6/7] scsi: Introduce scsi_req_cancel_async, Fam Zheng, 2014/09/29
- [Qemu-devel] [PATCH v5 7/7] virtio-scsi: Handle TMF request cancellation asynchronously, Fam Zheng, 2014/09/29
- Re: [Qemu-devel] [PATCH v5 7/7] virtio-scsi: Handle TMF request cancellation asynchronously,
Paolo Bonzini <=