linux-kernel - Re: [PATCH] dmaengine: stm32-dmamux: fix pm_runtime_get

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Message-ID: <CAEkB2ERfzxwkixX75CzCMeRRv51v-fM2zo2gpQrjtgaBZ_nNHQ@mail.gmail.com>
Date:   Wed, 24 Jun 2020 02:56:51 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     Vinod Koul <vkoul@...nel.org>
Cc:     Dan Williams <dan.j.williams@...el.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        dmaengine@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org,
        LKML <linux-kernel@...r.kernel.org>,
        Navid Emamdoost <emamd001@....edu>,
        Qiushi Wu <wu000273@....edu>, Kangjie Lu <kjlu@....edu>,
        Stephen McCamant <smccaman@....edu>
Subject: Re: [PATCH] dmaengine: stm32-dmamux: fix pm_runtime_get_sync fialure cases

On Wed, Jun 24, 2020 at 2:40 AM Vinod Koul <vkoul@...nel.org> wrote:
>
> On 03-06-20, 14:36, Navid Emamdoost wrote:
>
> s/fialure/failure
>
> > Calling pm_runtime_get_sync increments the counter even in case of
> > failure, causing incorrect ref count. Call pm_runtime_put_sync if
> > pm_runtime_get_sync fails.
> >
> > Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
> > ---
> >  drivers/dma/stm32-dmamux.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c
> > index 12f7637e13a1..ab250d7eed29 100644
> > --- a/drivers/dma/stm32-dmamux.c
> > +++ b/drivers/dma/stm32-dmamux.c
> > @@ -140,6 +140,7 @@ static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
> >       ret = pm_runtime_get_sync(&pdev->dev);
> >       if (ret < 0) {
> >               spin_unlock_irqrestore(&dmamux->lock, flags);
> > +             pm_runtime_put_sync(&pdev->dev);
>
> why put_sync()
>
> >               goto error;
> >       }
> >       spin_unlock_irqrestore(&dmamux->lock, flags);
> > @@ -340,8 +341,10 @@ static int stm32_dmamux_suspend(struct device *dev)
> >       int i, ret;
> >
> >       ret = pm_runtime_get_sync(dev);
> > -     if (ret < 0)
> > +     if (ret < 0) {
> > +             pm_runtime_put_sync(dev);
>
> here too

Is put_noidle() better?

>
> >               return ret;
> > +     }
> >
> >       for (i = 0; i < stm32_dmamux->dma_requests; i++)
> >               stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
> > --
> > 2.17.1
>
> --
> ~Vinod



-- 
Navid.