Re: [Qemu-devel] libiscsi task cancellation

[Stefan Hajnoczi]

On Thu, Feb 8, 2018 at 3:08 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Thu, Feb 8, 2018 at 2:14 PM, Paolo Bonzini <address@hidden> wrote:
>> On 08/02/2018 15:08, Stefan Hajnoczi wrote:
> I think users *can* work around the iscsi_task_mgmt_async() issue as follows:
>
> If the command callback has not been invoked yet when the ABORT TASK
> TMF callback is invoked, call iscsi_scsi_cancel_task() so that
> libiscsi invokes the command callback with SCSI_STATUS_CANCELLED and
> frees the PDU.
>
> Here is how that looks in QEMU:
>
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 8140baac15..7b4b43dc55 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -290,8 +290,12 @@ iscsi_abort_task_cb(struct iscsi_context *iscsi,
> int status, void *command_data,
>  {
>      IscsiAIOCB *acb = private_data;
>
> -    acb->status = -ECANCELED;
> -    iscsi_schedule_bh(acb);
> +    /* If the command callback hasn't been called yet, drop the task */
> +    if (!acb->bh) {
> +        /* Call iscsi_aio_ioctl_cb() with SCSI_STATUS_CANCELLED */
> +        iscsi_scsi_cancel_task(iscsi, acb->task);
> +    }
> +
>      qemu_aio_unref(acb); /* acquired in iscsi_aio_cancel() */
>  }

By the way, this is on top of
https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg00570.html.

Stefan