* [PATCH] drm/msm: avoid using 'timespec' @ 2018-06-18 15:39 Arnd Bergmann 2018-07-10 20:47 ` Sean Paul 0 siblings, 1 reply; 4+ messages in thread From: Arnd Bergmann @ 2018-06-18 15:39 UTC (permalink / raw) To: Rob Clark, David Airlie Cc: y2038, Arnd Bergmann, Jordan Crouse, Sean Paul, linux-arm-msm, dri-devel, freedreno, linux-kernel 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); } return remaining_jiffies; -- 2.9.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/msm: avoid using 'timespec' 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 0 siblings, 1 reply; 4+ messages in thread From: Sean Paul @ 2018-07-10 20:47 UTC (permalink / raw) To: Arnd Bergmann Cc: Rob Clark, David Airlie, y2038, Jordan Crouse, Sean Paul, linux-arm-msm, dri-devel, freedreno, linux-kernel 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? Sean > } > > return remaining_jiffies; > -- > 2.9.0 > -- Sean Paul, Software Engineer, Google / Chromium OS ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/msm: avoid using 'timespec' 2018-07-10 20:47 ` Sean Paul @ 2018-07-10 21:27 ` Arnd Bergmann 2018-07-11 14:00 ` Sean Paul 0 siblings, 1 reply; 4+ messages in thread From: Arnd Bergmann @ 2018-07-10 21:27 UTC (permalink / raw) To: Sean Paul Cc: Rob Clark, David Airlie, y2038 Mailman List, Jordan Crouse, linux-arm-msm, dri-devel, freedreno, Linux Kernel Mailing List 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] drm/msm: avoid using 'timespec' 2018-07-10 21:27 ` Arnd Bergmann @ 2018-07-11 14:00 ` Sean Paul 0 siblings, 0 replies; 4+ messages in thread From: Sean Paul @ 2018-07-11 14:00 UTC (permalink / raw) To: Arnd Bergmann Cc: Sean Paul, Rob Clark, David Airlie, y2038 Mailman List, Jordan Crouse, linux-arm-msm, dri-devel, freedreno, Linux Kernel Mailing List On Tue, Jul 10, 2018 at 11:27:00PM +0200, Arnd Bergmann wrote: > 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. Hey Arnd, Ahh, ok, I think I realize my confusion now. If ktime_t was not ns, ktime_divns() would do the conversion for us. Since it is ns, the conversion is a no-op (which is why I didn't see ktime_to_ns() in ktime_divns()). Thanks for breaking that down for me, Reviewed-by: Sean Paul <seanpaul@chromium.org> > > Arnd -- Sean Paul, Software Engineer, Google / Chromium OS ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-07-11 14:00 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 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 2018-07-11 14:00 ` Sean Paul
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