<div dir="ltr"><div><div>Hello Kevin,<br><br></div>As far as my understanding goes regarding ubus and uloop, they were not designed with threading in mind.<br></div><div></div><div></div>Also, as a general rule when using uloop, you wouldn't use threads, because races could occur (especially when doing ubus calls inside a thread) and the main uloop loop would terminate.<br><div><div><div></div><div><br>One general rule would be: you should not use ubus call in threads.<br></div><div></div><div>You could use ubus_invoke_async() instead of ubus_invoke().<br></div><div>It is a bit more work than just using ubus_invoke() but if you want thread-like behaviour, it could replace all the threads you're using.<br></div><div><br>So, is there a way to re-design your code without using threads and using ubus async calls ?<br><br></div><div><br></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 3, 2015 at 5:24 AM, XiaoFengMeng <span dir="ltr"><<a href="mailto:xiaofeng.meng@pfsw.com" target="_blank">xiaofeng.meng@pfsw.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">HI !<u></u><u></u></p>
<p class="MsoNormal">I am Kevin and learning the ubus code and got something that is confusing me very much in the code.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">My question is regarding code in ubus_invoke -> ubus_complete_request,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I can see that there are lots of uloop related code in “ubus_complete_request”<u></u><u></u></p>
<p class="MsoNormal">if (!registered) {<u></u><u></u></p>
<p class="MsoNormal"> uloop_init();<u></u><u></u></p>
<p class="MsoNormal"> ubus_add_uloop(ctx);<u></u><u></u></p>
<p class="MsoNormal">}<u></u><u></u></p>
<p class="MsoNormal">….<u></u><u></u></p>
<p class="MsoNormal">while (!req->status_msg) {<u></u><u></u></p>
<p class="MsoNormal"> bool cancelled = uloop_cancelled;<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"> uloop_cancelled = false;<u></u><u></u></p>
<p class="MsoNormal"> if (req_timeout) {<u></u><u></u></p>
<p class="MsoNormal"> timeout = time_end - get_time_msec();<u></u><u></u></p>
<p class="MsoNormal"> if (timeout <= 0) {<u></u><u></u></p>
<p class="MsoNormal"> ubus_set_req_status(req, UBUS_STATUS_TIMEOUT);<u></u><u></u></p>
<p class="MsoNormal"> break;<u></u><u></u></p>
<p class="MsoNormal"> }<u></u><u></u></p>
<p class="MsoNormal"> }<u></u><u></u></p>
<p class="MsoNormal"> ubus_poll_data(ctx, (unsigned int) timeout);<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"> uloop_cancelled = cancelled;<u></u><u></u></p>
<p class="MsoNormal"> }<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">My question is why is uloop involved here? uloop could be working in another thread and also listen on the same socket.<u></u><u></u></p>
<p class="MsoNormal">I idea that, before the ubus_invoke sends the request messge, it should disable the uloop for the current socket, so that code in uloop_run will not receive anything from the same socket.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Because after calling ubus_add_uloop(ctx), the uloop_run could also be receiving the response data<u></u><u></u></p>
<p class="MsoNormal">And this function could cause the uloop_run to quit the while loop.<u></u><u></u></p>
<p class="MsoNormal">How should I understand the logic here?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">And How should I do if I want to call ubus_invoke as a client and use uloop_run as a server at the same process?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thanks very much!<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Best regards<u></u><u></u></p>
<p class="MsoNormal">Kevin<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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