linux-kernel - Re: [PATCH] soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free

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Message-ID: <CAD=FV=V2NduvgdrSNOs7Ufm+=Tk3+rtkSoJg8BH7cYtOdCHXcA@mail.gmail.com>
Date:   Fri, 24 Jul 2020 13:31:39 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Maulik Shah <mkshah@...eaurora.org>,
        Lina Iyer <ilina@...eaurora.org>
Subject: Re: [PATCH] soc: qcom: rpmh-rsc: Sleep waiting for tcs slots to be free

Hi,

On Fri, Jul 24, 2020 at 1:27 PM Stephen Boyd <swboyd@...omium.org> wrote:
>
> Quoting Doug Anderson (2020-07-24 13:11:59)
> >
> > I wasn't suggesting adding a timeout.  I was just saying that if
> > claim_tcs_for_req() were to ever return an error code other than
> > -EBUSY that we'd need a check for it because otherwise we'd interpret
> > the result as a tcs_id.
> >
>
> Ok that sounds like you don't want a check for -EBUSY so I'll leave this
> as >= 0.

To clarify, I'd be OK with either of these (slight preference towards
#2, but not a strong one):

1. Your current code and a REALLY OBVIOUS comment in
claim_tcs_for_req() saying that we'd better not return any error codes
other than -EBUSY (because we'll just blindly retry on all of them).

- or -

2. Handling error codes other than -EBUSY, like this:

wait_event_lock_irq(drv->tcs_wait,
                    (tcs_id = claim_tcs_for_req(drv, tcs, msg)) != -EBUSY,
                    drv->lock);
if (tcs_id < 0)
  goto unlock;

-Doug