[Qemu-devel] [RFC PATCH 3/5] job: Drop AioContext lock around aio_poll()

[Kevin Wolf <kwolf@redhat.com>]

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 <kwolf@redhat.com>
---
 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);
-- 
2.13.6