monitor: use aio_co_reschedule_self()
The aio_co_reschedule_self() API is designed to avoid the race condition between scheduling the coroutine in another AioContext and yielding. The QMP dispatch code uses the open-coded version that appears susceptible to the race condition at first glance: aio_co_schedule(qemu_get_aio_context(), qemu_coroutine_self()); qemu_coroutine_yield(); The code is actually safe because the iohandler and qemu_aio_context AioContext run under the Big QEMU Lock. Nevertheless, set a good example and use aio_co_reschedule_self() so it's obvious that there is no race. Suggested-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20240206190610.107963-6-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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@ -212,8 +212,7 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ
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* executing the command handler so that it can make progress if it
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* involves an AIO_WAIT_WHILE().
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*/
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aio_co_schedule(qemu_get_aio_context(), qemu_coroutine_self());
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qemu_coroutine_yield();
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aio_co_reschedule_self(qemu_get_aio_context());
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}
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monitor_set_cur(qemu_coroutine_self(), cur_mon);
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@ -227,9 +226,7 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ
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* Move back to iohandler_ctx so that nested event loops for
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* qemu_aio_context don't start new monitor commands.
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*/
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aio_co_schedule(iohandler_get_aio_context(),
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qemu_coroutine_self());
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qemu_coroutine_yield();
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aio_co_reschedule_self(iohandler_get_aio_context());
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}
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} else {
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/*
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