block: mark aio_poll as non-coroutine

It is forbidden to block on the event loop during a coroutine, as that
can cause deadlocks due to recursive locking.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20230908075458.527013-1-pbonzini@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/block/aio.h

@@ -467,7 +467,7 @@ void aio_dispatch(AioContext *ctx);
  * or more AIO events have completed, to ensure something has moved
  * before returning.
  */
-bool aio_poll(AioContext *ctx, bool blocking);
+bool no_coroutine_fn aio_poll(AioContext *ctx, bool blocking);
 
 /* Register a file descriptor and associated callbacks.  Behaves very similarly
  * to qemu_set_fd_handler.  Unlike qemu_set_fd_handler, these callbacks will