Il 25/09/2014 04:20, Fam Zheng ha scritto:
> Devices will call this function to start an asynchronous cancellation. The
> bus->info->cancel will be called after the request is canceled.
>
> Devices will probably need to track a separate TMF request that triggers this
> cancellation, and wait until the cancellation is done before completing it. So
> we store a notifier list in SCSIRequest and in scsi_req_cancel_complete we
> notify them.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> hw/scsi/scsi-bus.c | 23 +++++++++++++++++++++++
> include/hw/scsi/scsi.h | 3 +++
> 2 files changed, 26 insertions(+)
>
> diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
> index c91db63..df7585a 100644
> --- a/hw/scsi/scsi-bus.c
> +++ b/hw/scsi/scsi-bus.c
> @@ -566,6 +566,7 @@ SCSIRequest *scsi_req_alloc(const SCSIReqOps *reqops,
> SCSIDevice *d,
> req->ops = reqops;
> object_ref(OBJECT(d));
> object_ref(OBJECT(qbus->parent));
> + notifier_list_init(&req->cancel_notifiers);
> trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
> return req;
> }
> @@ -1725,9 +1726,31 @@ void scsi_req_cancel_complete(SCSIRequest *req)
> if (req->bus->info->cancel) {
> req->bus->info->cancel(req);
> }
> + notifier_list_notify(&req->cancel_notifiers, req);
I think you also have to call notifier_list_notify from
scsi_req_complete, because a cancelled request might end up being
completed instead of cancelled.
In fact, the next obvious step (enabled by your bdrv_aio_cancel cleanup)
would be to _not_ call scsi_req_cancel_complete if we can report
completion or if there was an I/O error. This can happen for
scsi-generic, scsi_dma_complete_noio, etc. Basically, moving the
io_canceled check from the beginning of the completion routine to just
before bdrv_aio_* or dma_aio_* are called.
Paolo
> scsi_req_unref(req);
> }
>
> +/* Cancel @req asynchronously. @notifier is added to @req's cancellation
> + * notifier list, the bus will be notified the requests cancellation is
> + * completed.
> + * */
> +void scsi_req_cancel_async(SCSIRequest *req, Notifier *notifier)
> +{
> + trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
> + if (notifier) {
> + notifier_list_add(&req->cancel_notifiers, notifier);
> + }
> + if (req->io_canceled) {
> + return;
> + }
> + scsi_req_ref(req);
> + scsi_req_dequeue(req);
> + req->io_canceled = true;
> + if (req->aiocb) {
> + bdrv_aio_cancel_async(req->aiocb);
> + }
> +}
> +
> void scsi_req_cancel(SCSIRequest *req)
> {
> trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
> diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
> index a75a7c8..c47dc53 100644
> --- a/include/hw/scsi/scsi.h
> +++ b/include/hw/scsi/scsi.h
> @@ -5,6 +5,7 @@
> #include "block/block.h"
> #include "hw/block/block.h"
> #include "sysemu/sysemu.h"
> +#include "qemu/notify.h"
>
> #define MAX_SCSI_DEVS 255
>
> @@ -53,6 +54,7 @@ struct SCSIRequest {
> void *hba_private;
> size_t resid;
> SCSICommand cmd;
> + NotifierList cancel_notifiers;
>
> /* Note:
> * - fields before sense are initialized by scsi_req_alloc;
> @@ -267,6 +269,7 @@ int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf,
> int len);
> void scsi_req_abort(SCSIRequest *req, int status);
> void scsi_req_cancel_complete(SCSIRequest *req);
> void scsi_req_cancel(SCSIRequest *req);
> +void scsi_req_cancel_async(SCSIRequest *req, Notifier *notifier);
> void scsi_req_retry(SCSIRequest *req);
> void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense);
> void scsi_device_set_ua(SCSIDevice *sdev, SCSISense sense);
>
