linux-kernel - Re: [PATCH] clocksource/drivers/integrator-ap: add missing of_node

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Date:   Sun, 25 Nov 2018 12:25:19 +0800
From:   Frank Lee <tiny.windzz@...il.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clocksource/drivers/integrator-ap: add missing of_node_put()

On Sun, Nov 25, 2018 at 3:49 AM Daniel Lezcano
<daniel.lezcano@...aro.org> wrote:
>
> On 24/11/2018 15:58, Frank Lee wrote:
> > On Thu, Nov 22, 2018 at 11:23 PM Yangtao Li <tiny.windzz@...il.com> wrote:
> >>
> >> of_find_node_by_path() acquires a reference to the node
> >> returned by it and that reference needs to be dropped by its caller.
> >> integrator_ap_timer_init_of() doesn't do that, so fix it.
> >>
> >> Signed-off-by: Yangtao Li <tiny.windzz@...il.com>
> >> ---
> >>  drivers/clocksource/timer-integrator-ap.c | 20 ++++++++++++++------
> >>  1 file changed, 14 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/clocksource/timer-integrator-ap.c b/drivers/clocksource/timer-integrator-ap.c
> >> index 76e526f58620..1f04069470bb 100644
> >> --- a/drivers/clocksource/timer-integrator-ap.c
> >> +++ b/drivers/clocksource/timer-integrator-ap.c
> >> @@ -177,7 +177,7 @@ static int __init integrator_ap_timer_init_of(struct device_node *node)
> >>  {
> >>         const char *path;
> >>         void __iomem *base;
> >> -       int err;
> >> +       int err,rc = 0;
> >>         int irq;
> >>         struct clk *clk;
> >>         unsigned long rate;
> >> @@ -210,26 +210,34 @@ static int __init integrator_ap_timer_init_of(struct device_node *node)
> >>                                 "arm,timer-secondary", &path);
> >>         if (err) {
> >>                 pr_warn("Failed to read property\n");
> >> -               return err;
> >> +               rc = err;
> >> +               goto out_put_pri_node;
> >>         }
> >>
> >>
> >>         sec_node = of_find_node_by_path(path);
> >>
> >> -       if (node == pri_node)
> >> +       if (node == pri_node){
> >>                 /* The primary timer lacks IRQ, use as clocksource */
> >> -               return integrator_clocksource_init(rate, base);
> >> +               rc = integrator_clocksource_init(rate, base);
> >> +               goto out;
> >> +       }
> >>
> >>         if (node == sec_node) {
> >>                 /* The secondary timer will drive the clock event */
> >>                 irq = irq_of_parse_and_map(node, 0);
> >> -               return integrator_clockevent_init(rate, base, irq);
> >> +               rc = integrator_clockevent_init(rate, base, irq);
> >> +               goto out;
> >>         }
> >>
> >>         pr_info("Timer @%p unused\n", base);
> >>         clk_disable_unprepare(clk);
> >> +out:
> >> +       of_node_put(sec_node);
> >> +out_put_pri_node:
> >> +       of_node_put(pri_node);
> >>
> >> -       return 0;
> >> +       return rc;
> >>  }
> >>
> >>  TIMER_OF_DECLARE(integrator_ap_timer, "arm,integrator-timer",
> >> --
> >> 2.17.0
> >>
> > Hi Daniel：
> >
> > How about this?
>
> Hi,
>
> I think there is a simpler fix. The pri_node and the sec_node are used
> as an identifier to compare against the current node, we can directly
> drop the refcount after getting the node from path as it is not used as
> pointer. In addition, a single variable is needed, so we end up with a
> fix like that.
>
>         alias_node = of_find_node_by_path(path);
>         of_node_put(alias_node);
>         if (node == alias_node)
>                 return integrator_clocksource_init(rate, base);

Daniel,

OK,I will simplify it like you said.Although I think of_node_put
should be called
after we don't use node.

MBR，
Yangtao
>
>
>
> >
> > Thanks，
> > Yangtao
> >
>
>
> --
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