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Re: [Qemu-devel] [PATCH] scsi: always call notifier on async cancellatio
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH] scsi: always call notifier on async cancellation |
Date: |
Thu, 17 Dec 2015 20:22:33 +0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, 12/17 09:41, Paolo Bonzini wrote:
>
>
> On 17/12/2015 02:15, Fam Zheng wrote:
> >> > 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) {
> > blk_aio_cancel_async(req->aiocb);
> > } else {
> > scsi_req_cancel_complete(req);
> > }
> >
> > A second TMF must be blk_aio_cancel_async case, otherwise the first one
> > would
> > have already completed the request synchronously in
> > scsi_req_cancel_complete.
>
> Good point.
>
> > With that in mind, I think returning early is not a problem. But I suppose
> > these are also idempotent so this change is not breaking anything, either.
>
> Right, the issue is that all these calls are idempotent, but the
> notifier may not; that is why I prefer to be safe and ensure that all
> notifier additions are matched by a notify. But you explained well why
> this should be safe, I'll add a note to the commit message.
>
Thanks, please add my
Reviewed-by: Fam Zheng <address@hidden>