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Re: [Qemu-devel] [RFC PATCH 6/9] blkdebug: Implement .cancel_async
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [RFC PATCH 6/9] blkdebug: Implement .cancel_async |
Date: |
Fri, 22 Aug 2014 12:29:17 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, 08/21 17:52, Stefan Hajnoczi wrote:
> On Thu, Aug 21, 2014 at 07:56:53PM +0800, Fam Zheng wrote:
> > @@ -446,12 +439,25 @@ static void error_callback_bh(void *opaque)
> > qemu_aio_release(acb);
> > }
> >
> > +static void blkdebug_aio_cancel_async(BlockDriverAIOCB *blockacb)
> > +{
> > + BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
> > + blockacb->cb(blockacb->opaque, -ECANCELED);
> > + qemu_aio_release(acb);
> > +}
> > +
> > static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
> > {
> > BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
> > qemu_aio_release(acb);
> > }
>
> Both blkdebug_aio_cancel() and blkdebug_aio_cancel_async() look
> incorrect. It is not safe to release acb because the
> error_callback_bh() BH may still be scheduled.
>
> I guess we don't hit this problem because the error injection happens
> within the same event loop iteration. In practice no one ever calls
> blkdebug_aio_cancel()?
>
I'll drop this patch and send a separate fix for blkdebug_aio_cancel.
Fam
- [Qemu-devel] [RFC PATCH 4/9] linux-aio: Implement .cancel_async, (continued)
- [Qemu-devel] [RFC PATCH 4/9] linux-aio: Implement .cancel_async, Fam Zheng, 2014/08/21
- [Qemu-devel] [RFC PATCH 5/9] thread-pool: Implement .cancel_async, Fam Zheng, 2014/08/21
- [Qemu-devel] [RFC PATCH 7/9] dma: Implement .cancel_async, Fam Zheng, 2014/08/21
- [Qemu-devel] [RFC PATCH 8/9] block: Implement stub bdrv_em_co_aiocb_info.cancel_async, Fam Zheng, 2014/08/21
- [Qemu-devel] [RFC PATCH 6/9] blkdebug: Implement .cancel_async, Fam Zheng, 2014/08/21
- [Qemu-devel] [RFC PATCH 9/9] scsi: Cancel request asynchronously, Fam Zheng, 2014/08/21