linux-kernel - Re: [PATCH] intel_ips: Convert timers to use timer

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Date:   Thu, 5 Oct 2017 11:41:18 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] intel_ips: Convert timers to use timer_setup()

On Thu, Oct 5, 2017 at 3:54 AM, Kees Cook <keescook@...omium.org> wrote:
> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly. Moves timer structure off stack and
> into struct ips_driver.

Pushed to my testing queue, thanks!

>
> Cc: Darren Hart <dvhart@...radead.org>
> Cc: Andy Shevchenko <andy@...radead.org>
> Cc: platform-driver-x86@...r.kernel.org
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
> This requires commit 686fef928bba ("timer: Prepare to change timer
> callback argument type") in v4.14-rc3, but should be otherwise
> stand-alone.
> ---
>  drivers/platform/x86/intel_ips.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/platform/x86/intel_ips.c b/drivers/platform/x86/intel_ips.c
> index 58dcee562d64..056afb731d79 100644
> --- a/drivers/platform/x86/intel_ips.c
> +++ b/drivers/platform/x86/intel_ips.c
> @@ -300,6 +300,7 @@ struct ips_driver {
>         struct task_struct *monitor;
>         struct task_struct *adjust;
>         struct dentry *debug_root;
> +       struct timer_list timer;
>
>         /* Average CPU core temps (all averages in .01 degrees C for precision) */
>         u16 ctv1_avg_temp;
> @@ -942,9 +943,10 @@ static u32 calc_avg_power(struct ips_driver *ips, u32 *array)
>         return avg;
>  }
>
> -static void monitor_timeout(unsigned long arg)
> +static void monitor_timeout(struct timer_list *t)
>  {
> -       wake_up_process((struct task_struct *)arg);
> +       struct ips_driver *ips = from_timer(ips, t, timer);
> +       wake_up_process(ips->monitor);
>  }
>
>  /**
> @@ -961,7 +963,6 @@ static void monitor_timeout(unsigned long arg)
>  static int ips_monitor(void *data)
>  {
>         struct ips_driver *ips = data;
> -       struct timer_list timer;
>         unsigned long seqno_timestamp, expire, last_msecs, last_sample_period;
>         int i;
>         u32 *cpu_samples, *mchp_samples, old_cpu_power;
> @@ -1049,8 +1050,7 @@ static int ips_monitor(void *data)
>         schedule_timeout_interruptible(msecs_to_jiffies(IPS_SAMPLE_PERIOD));
>         last_sample_period = IPS_SAMPLE_PERIOD;
>
> -       setup_deferrable_timer_on_stack(&timer, monitor_timeout,
> -                                       (unsigned long)current);
> +       timer_setup(&ips->timer, monitor_timeout, TIMER_DEFERRABLE);
>         do {
>                 u32 cpu_val, mch_val;
>                 u16 val;
> @@ -1107,7 +1107,7 @@ static int ips_monitor(void *data)
>                 expire = jiffies + msecs_to_jiffies(IPS_SAMPLE_PERIOD);
>
>                 __set_current_state(TASK_INTERRUPTIBLE);
> -               mod_timer(&timer, expire);
> +               mod_timer(&ips->timer, expire);
>                 schedule();
>
>                 /* Calculate actual sample period for power averaging */
> @@ -1116,8 +1116,7 @@ static int ips_monitor(void *data)
>                         last_sample_period = 1;
>         } while (!kthread_should_stop());
>
> -       del_timer_sync(&timer);
> -       destroy_timer_on_stack(&timer);
> +       del_timer_sync(&ips->timer);
>
>         dev_dbg(&ips->dev->dev, "ips-monitor thread stopped\n");
>
> --
> 2.7.4
>
>
> --
> Kees Cook
> Pixel Security



-- 
With Best Regards,
Andy Shevchenko