From: John Snow <jsnow@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] dma-helpers: ensure AIO callback is invoked after cancellation
Date: Tue, 13 Aug 2019 18:40:19 -0400 [thread overview]
Message-ID: <b1135640-3e01-6e25-ecd0-375d57acb901@redhat.com> (raw)
In-Reply-To: <20190729213416.1972-1-pbonzini@redhat.com>
On 7/29/19 5:34 PM, Paolo Bonzini wrote:
> dma_aio_cancel unschedules the BH if there is one, which corresponds
> to the reschedule_dma case of dma_blk_cb. This can stall the DMA
> permanently, because dma_complete will never get invoked and therefore
> nobody will ever invoke the original AIO callback in dbs->common.cb.
>
> Fix this by invoking the callback (which is ensured to happen after
> a bdrv_aio_cancel_async, or done manually in the dbs->bh case), and
> add assertions to check that the DMA state machine is indeed waiting
> for dma_complete or reschedule_dma, but never both.
>
> Reported-by: John Snow <jsnow@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
No maintainer here, I guess; Paolo will you be pulling this or should I
do it as part of the other IDE fixes I need to make?
--js
next prev parent reply other threads:[~2019-08-13 22:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 21:34 [Qemu-devel] [PATCH] dma-helpers: ensure AIO callback is invoked after cancellation Paolo Bonzini
2019-07-29 21:46 ` John Snow
2019-07-29 21:51 ` Paolo Bonzini
2019-07-29 22:00 ` John Snow
2019-08-13 22:40 ` John Snow [this message]
2019-08-13 22:49 ` John Snow
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