Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
In-Reply-To: <20200424094610.v5.4.Ib8dccfdb10bf6b1fb1d600ca1c21d9c0db1ef746@changeid>
References: <20200424094610.v5.1.Ic7096b3b9b7828cdd41cd5469a6dee5eb6abf549@changeid> <20200424094610.v5.4.Ib8dccfdb10bf6b1fb1d600ca1c21d9c0db1ef746@changeid>
Subject: Re: [PATCH v5 4/5] soc: qcom: rpmh-rsc: Simplify locking by eliminating the per-TCS lock
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     evgreen@chromium.org, mka@chromium.org, mkshah@codeaurora.org,
        Douglas Anderson <dianders@chromium.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
To:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Douglas Anderson <dianders@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rafael.j.wysocki@intel.com
Date:   Fri, 24 Apr 2020 11:06:06 -0700
Message-ID: <158775156694.135303.3535369004080151247@swboyd.mtv.corp.google.com>
User-Agent: alot/0.9
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Quoting Douglas Anderson (2020-04-24 09:46:56)
> @@ -581,24 +575,19 @@ static int tcs_write(struct rsc_drv *drv, const str=
uct tcs_request *msg)
>         if (IS_ERR(tcs))
>                 return PTR_ERR(tcs);
> =20
> -       spin_lock_irqsave(&tcs->lock, flags);
> -       spin_lock(&drv->lock);
> +       spin_lock_irqsave(&drv->lock, flags);
>         /*
>          * The h/w does not like if we send a request to the same address,
>          * when one is already in-flight or being processed.
>          */
>         ret =3D check_for_req_inflight(drv, tcs, msg);
> -       if (ret) {
> -               spin_unlock(&drv->lock);
> -               goto done_write;
> -       }
> +       if (ret)
> +               goto unlock;
> =20
> -       tcs_id =3D find_free_tcs(tcs);
> -       if (tcs_id < 0) {
> -               ret =3D tcs_id;
> -               spin_unlock(&drv->lock);
> -               goto done_write;
> -       }
> +       ret =3D find_free_tcs(tcs);
> +       if (ret < 0)
> +               goto unlock;
> +       tcs_id =3D ret;

Sorry, missed this. We should keep the tcs_id =3D find_free_tcs() thing
and then assign ret to it on failure. Otherwise the return value of this
function is -EBUSY or the tcs_id number instead of -EBUSY or 0.

> =20
>         tcs->req[tcs_id - tcs->offset] =3D msg;
>         set_bit(tcs_id, drv->tcs_in_use);