From: Arnd Bergmann <arnd@arndb.de>
To: Sean Paul <seanpaul@chromium.org>
Cc: Rob Clark <robdclark@gmail.com>, David Airlie <airlied@linux.ie>,
y2038 Mailman List <y2038@lists.linaro.org>,
Jordan Crouse <jcrouse@codeaurora.org>,
linux-arm-msm@vger.kernel.org,
dri-devel <dri-devel@lists.freedesktop.org>,
freedreno@lists.freedesktop.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm/msm: avoid using 'timespec'
Date: Tue, 10 Jul 2018 23:27:00 +0200 [thread overview]
Message-ID: <CAK8P3a0j7O8MdpxiGNKfrRB5Sdx0UJzH_=4diRw6a-0TKoUAdw@mail.gmail.com> (raw)
In-Reply-To: <20180710204736.GU20303@art_vandelay>
On Tue, Jul 10, 2018 at 10:47 PM, Sean Paul <seanpaul@chromium.org> wrote:
> On Mon, Jun 18, 2018 at 05:39:42PM +0200, Arnd Bergmann wrote:
>> The timespec structure and associated interfaces are deprecated and will
>> be removed in the future because of the y2038 overflow.
>>
>> The use of ktime_to_timespec() in timeout_to_jiffies() does not
>> suffer from that overflow, but is easy to avoid by just converting
>> the ktime_t into jiffies directly.
>>
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> ---
>> drivers/gpu/drm/msm/msm_drv.h | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
>> index b2da1fbf81e0..cc8977476a41 100644
>> --- a/drivers/gpu/drm/msm/msm_drv.h
>> +++ b/drivers/gpu/drm/msm/msm_drv.h
>> @@ -353,8 +353,7 @@ static inline unsigned long timeout_to_jiffies(const ktime_t *timeout)
>> remaining_jiffies = 0;
>> } else {
>> ktime_t rem = ktime_sub(*timeout, now);
>> - struct timespec ts = ktime_to_timespec(rem);
>> - remaining_jiffies = timespec_to_jiffies(&ts);
>> + remaining_jiffies = ktime_divns(rem, NSEC_PER_SEC / HZ);
>
> Do you need to wrap rem in ktime_to_ns() just to be safe?
The ktime_t interfaces are still defined to use an opaque type,
as previously it was a union that could be a seconds/nanoseconds
pair depending on the architecture. These days, ktime_t is just
a 64-bit integer, so div_u64() would work just as well as ktime_divns(),
but this is the documented way to do it.
Arnd
next prev parent reply other threads:[~2018-07-10 21:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 15:39 [PATCH] drm/msm: avoid using 'timespec' Arnd Bergmann
2018-07-10 20:47 ` Sean Paul
2018-07-10 21:27 ` Arnd Bergmann [this message]
2018-07-11 14:00 ` Sean Paul
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