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blockjob: Wake up BDS when job becomes idle

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In the context of draining a BDS, the .drained_poll callback of block
jobs is called. If this returns true (i.e. there is still some activity
pending), the drain operation may call aio_poll() with blocking=true to
wait for completion.

As soon as the pending activity is completed and the job finally arrives
in a quiescent state (i.e. its coroutine either yields with busy=false
or terminates), the block job must notify the aio_poll() loop to wake
up, otherwise we get a deadlock if both are running in different
threads.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf
2018-08-17 14:53:05 +02:00
parent d1756c780b
commit 34dc97b9a0
4 changed files with 41 additions and 0 deletions
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7
job.c
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@ -402,6 +402,11 @@ static void job_event_ready(Job *job)
notifier_list_notify(&job->on_ready, job);
}
static void job_event_idle(Job *job)
{
notifier_list_notify(&job->on_idle, job);
}
void job_enter_cond(Job *job, bool(*fn)(Job *job))
{
if (!job_started(job)) {
@ -447,6 +452,7 @@ static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
job_event_idle(job);
job_unlock();
qemu_coroutine_yield();
@ -865,6 +871,7 @@ static void coroutine_fn job_co_entry(void *opaque)
assert(job && job->driver && job->driver->run);
job_pause_point(job);
job->ret = job->driver->run(job, &job->err);
job_event_idle(job);
job->deferred_to_main_loop = true;
aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
}