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Re: [Qemu-block] [RFC PATCH 3/5] job: Drop AioContext lock around aio_po
From: |
Fam Zheng |
Subject: |
Re: [Qemu-block] [RFC PATCH 3/5] job: Drop AioContext lock around aio_poll() |
Date: |
Fri, 24 Aug 2018 15:22:05 +0800 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Fri, 08/17 19:02, Kevin Wolf wrote:
> Simimlar to AIO_WAIT_WHILE(), job_finish_sync() needs to release the
> AioContext lock of the job before calling aio_poll(). Otherwise,
> callbacks called by aio_poll() would possibly take the lock a second
> time and run into a deadlock with a nested AIO_WAIT_WHILE() call.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> job.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/job.c b/job.c
> index a746bfe70b..6acf55bceb 100644
> --- a/job.c
> +++ b/job.c
> @@ -1016,7 +1016,10 @@ int job_finish_sync(Job *job, void (*finish)(Job *,
> Error **errp), Error **errp)
> job_drain(job);
> }
> while (!job_is_completed(job)) {
> + AioContext *aio_context = job->aio_context;
> + aio_context_release(aio_context);
> aio_poll(qemu_get_aio_context(), true);
> + aio_context_acquire(aio_context);
> }
> ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
> job_unref(job);
Why doesn't this function just use AIO_WAIT_WHILE()?
Fam
- [Qemu-block] [RFC PATCH 0/5] Fix some jobs/drain/aio_poll related hangs, Kevin Wolf, 2018/08/17
- [Qemu-block] [RFC PATCH 1/5] blockjob: Wake up BDS when job becomes idle, Kevin Wolf, 2018/08/17
- [Qemu-block] [RFC PATCH 2/5] tests: Acquire AioContext around job_finish_sync(), Kevin Wolf, 2018/08/17
- [Qemu-block] [RFC PATCH 3/5] job: Drop AioContext lock around aio_poll(), Kevin Wolf, 2018/08/17
- Re: [Qemu-block] [RFC PATCH 3/5] job: Drop AioContext lock around aio_poll(),
Fam Zheng <=
- [Qemu-block] [RFC PATCH 4/5] block: Drop AioContext lock in bdrv_drain_poll_top_level(), Kevin Wolf, 2018/08/17
- [Qemu-block] [RFC PATCH 5/5] [WIP] Lock AioContext in bdrv_co_drain_bh_cb(), Kevin Wolf, 2018/08/17
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH 0/5] Fix some jobs/drain/aio_poll related hangs, no-reply, 2018/08/18
- Re: [Qemu-block] [RFC PATCH 0/5] Fix some jobs/drain/aio_poll related hangs, Fam Zheng, 2018/08/21