Re: [PATCH 1/1] Staging: hv: mousevsc: Move the mouse driver out ofstaging

From: Dmitry Torokhov
Date: Wed Oct 26 2011 - 20:09:43 EST


On Sun, Oct 23, 2011 at 03:45:14PM +0000, KY Srinivasan wrote:
> > > +
> > > + t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
> > > + if (t == 0) {
> > > + ret = -ETIMEDOUT;
> > > + goto cleanup;
> > > + }
> > > +
> > > + response = &input_dev->protocol_resp;
> > > +
> > > + if (!response->response.approved) {
> > > + pr_err("synthhid protocol request failed (version %d)",
> > > + SYNTHHID_INPUT_VERSION);
> > > + ret = -ENODEV;
> > > + goto cleanup;
> > > + }
> > > +
> > > + t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
> >
> > We just completed the wait for this completion, why are we waiting on
> > the same completion again?
>
> In response to our initial query, we expect the host to respond back with two
> distinct pieces of information; we wait for both these responses.

I think you misunderstand how completion works in Linux. IIRC about
Windows events they are different ;) You can not signal completion
several times and then expect to wait corrsponding number of times. Once
you signal completion is it, well, complete.

>
> >
> > > + if (t == 0) {
> > > + ret = -ETIMEDOUT;
> > > + goto cleanup;
> > > + }
> > > +
> > > + /*
> > > + * We should have gotten the device attr, hid desc and report
> > > + * desc at this point
> > > + */
> > > + if (input_dev->dev_info_status)
> > > + ret = -ENOMEM;
> >
> > -ENOMEM seems wrong.
> >
> There are many failures here and not being able to allocate memory is the
> primary one; and so I chose to capture that.

Any chance that these failures have their own exit paths?

Thanks.

--
Dmitry
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