On 1/27/22 13:22, Jinoh Kang wrote:
On 1/28/22 04:13, Jinoh Kang wrote:
On 1/28/22 04:05, Jinoh Kang wrote:
+/* Notify direct completion of async and close the wait handle */ +DECL_HANDLER(notify_async_direct_result) +{
- struct async *async = (struct async *)get_handle_obj( current->process, req->handle, 0, &async_ops );
- if (!async) return;
- if (async->iosb && async->unknown_status && !async->pending && async->terminated)
- {
/* Reactivate async. We call async_reselect() later. */async->terminated = 0;/* Set result for async_handoff(). */set_error( req->status );async->iosb->result = req->information;/* The async_handoff() call prior to the current server request was* effectively a no-op since async->unknown_status is 1. Calling it* again with async->unknown_status = 0 will do the remaining steps.*/async->unknown_status = 0;async_handoff( async, NULL, 0 );if (get_error() == STATUS_PENDING){async_reselect( async );}else if (NT_ERROR( get_error() )){/* synchronous I/O failure: don't invoke callbacks, only dequeue it. */async_dequeue( async );Note: we can't use async_set_result() here. async_handoff() leaves async->terminated as 0, and async_set_result() has "assert( async->terminated )".
Thus, reusing async_set_result() here requires either:
Setting async->pending to 0 so that async_handoff() will call async_terminate(). This is obviously incorrect since unwanted IOCP packets and APCs will fire on synchronous failure.
Not using async_handoff(). We have to copy a lot of code (particulary setting pending and direct_result flags) out of async_handoff() to do this.
Maybe just merge both branches (error/success) and force async_terminate() before calling async_set_result()?
Actually, I believe the right thing to do is just to set async->terminated = 1. In fact, I believe you should set async->terminated = 1 in the recv_socket request, otherwise async_waiting() will return 1 and the server will end up spinning and/or trying to wake the async. (Granted, that could be protected against by checking unknown_status, but...)
There are a few different ways to look at this, but one way (and what I think makes the most sense to me) is that we're completing the async as if it had been alerted, much as we would from a kernel APC, except that we're also setting the initial status, which wasn't known yet. Hence we want to go through async_set_result().
Along these lines, if you also set async->alerted = 1, you get the STATUS_PENDING "restart the wait" behaviour for free. Which makes conceptual sense as well.
I suppose this is why you mentioned direct_result in [1]—i.e. we could just async_terminate(STATUS_ALERTED) in recv_socket. I can see both approaches working, but I think that open-coding the relevant parts of async_terminate would be better than trying to get direct_result manipulation exactly right. Of course, I also haven't tried...
[1] https://www.winehq.org/pipermail/wine-devel/2022-January/205774.html