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Re: [Qemu-devel] [RFC PATCH 1/9] block: Add bdrv_aio_cancel_async
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] [RFC PATCH 1/9] block: Add bdrv_aio_cancel_async |
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Date: |
Fri, 22 Aug 2014 12:10:35 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 |
Il 22/08/2014 11:37, Fam Zheng ha scritto:
> Exactly. I'd rather not change the contract then.
>
> Alternatively, we may add a refcnt field to BlockDriverAioCB and grab one
> before
> calling .cancel, so the qemu_aio_release will not free it.
Yes, and I don't exclude that sooner or later we'll have to add
reference counts to AIOCB anyway. However, reference counting is not
_that_ cheap so for now I'd rather see other solutions explored.
The problem is implementing cancel_sync in terms of cancel. The
simplest solution, for now, is to make bdrv_aio_cancel_async return
false if the callback is not implemented, and fall back to synchronous
cancellation.
Paolo
Re: [Qemu-devel] [RFC PATCH 1/9] block: Add bdrv_aio_cancel_async, Stefan Hajnoczi, 2014/08/21
[Qemu-devel] [RFC PATCH 2/9] tests: Add testing code for bdrv_aio_cancel_async, Fam Zheng, 2014/08/21
[Qemu-devel] [RFC PATCH 3/9] iscsi: Implement .cancel_async in acb info, Fam Zheng, 2014/08/21
[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