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From:   Alistair Strachan <astrachan@google.com>
Date:   Thu, 21 Jun 2018 15:04:21 -0700
Message-ID: <CANDihLEgjnHX1F=JeuWjXvBDdQjw-JTr5+QoyPOJ5Jf1Q_zHTQ@mail.gmail.com>
Subject: Re: [PATCH] staging: android/vsoc: stop using 'timespec'
To:     arnd@arndb.de
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>, y2038@lists.linaro.org,
        riandrews@android.com, natechancellor@gmail.com,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
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On Mon, Jun 18, 2018 at 8:09 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> The timespec structure suffers from the y2038 overflow and should not
> be used. This changes handle_vsoc_cond_wait() to use ktime_t directly.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Tested-by: Alistair Strachan <astrachan@google.com>

> ---
>  drivers/staging/android/vsoc.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/android/vsoc.c b/drivers/staging/android/vsoc.c
> index 806beda1040b..22571abcaa4e 100644
> --- a/drivers/staging/android/vsoc.c
> +++ b/drivers/staging/android/vsoc.c
> @@ -405,7 +405,7 @@ static int handle_vsoc_cond_wait(struct file *filp, struct vsoc_cond_wait *arg)
>         int ret = 0;
>         struct vsoc_device_region *region_p = vsoc_region_from_filep(filp);
>         atomic_t *address = NULL;
> -       struct timespec ts;
> +       ktime_t wake_time;
>
>         /* Ensure that the offset is aligned */
>         if (arg->offset & (sizeof(uint32_t) - 1))
> @@ -433,14 +433,13 @@ static int handle_vsoc_cond_wait(struct file *filp, struct vsoc_cond_wait *arg)
>                  * We do things this way to flatten differences between 32 bit
>                  * and 64 bit timespecs.
>                  */
> -               ts.tv_sec = arg->wake_time_sec;
> -               ts.tv_nsec = arg->wake_time_nsec;
> -
> -               if (!timespec_valid(&ts))
> +               if (arg->wake_time_nsec >= NSEC_PER_SEC)
>                         return -EINVAL;
> +               wake_time = ktime_set(arg->wake_time_sec, arg->wake_time_nsec);
> +
>                 hrtimer_init_on_stack(&to->timer, CLOCK_MONOTONIC,
>                                       HRTIMER_MODE_ABS);
> -               hrtimer_set_expires_range_ns(&to->timer, timespec_to_ktime(ts),
> +               hrtimer_set_expires_range_ns(&to->timer, wake_time,
>                                              current->timer_slack_ns);
>
>                 hrtimer_init_sleeper(to, current);
> --
> 2.9.0
>