From: David Gibson <david@gibson.dropbear.id.au>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
John Stultz <john.stultz@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Liav Rehana <liavr@mellanox.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Richard Cochran <richardcochran@gmail.com>,
Parit Bhargava <prarit@redhat.com>,
Laurent Vivier <lvivier@redhat.com>,
"Christopher S. Hall" <christopher.s.hall@intel.com>
Subject: Re: [patch 2/6] timekeeping: Make the conversion call chain consistently unsigned
Date: Fri, 9 Dec 2016 10:39:22 +1100 [thread overview]
Message-ID: <20161208233922.GK13139@umbus.fritz.box> (raw)
In-Reply-To: <20161208204228.765843099@linutronix.de>
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On Thu, Dec 08, 2016 at 08:49:34PM -0000, Thomas Gleixner wrote:
> Propagating a unsigned value through signed variables and functions makes
> absolutely no sense and is just prone to (re)introduce subtle signed
> vs. unsigned issues as happened recently.
>
> Clean it up.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> kernel/time/timekeeping.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -311,7 +311,7 @@ static inline u64 timekeeping_delta_to_n
> return nsec + arch_gettimeoffset();
> }
>
> -static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
> +static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
> {
> cycle_t delta;
>
> @@ -319,8 +319,8 @@ static inline s64 timekeeping_get_ns(str
> return timekeeping_delta_to_ns(tkr, delta);
> }
>
> -static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
> - cycle_t cycles)
> +static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
> + cycle_t cycles)
> {
> cycle_t delta;
>
> @@ -623,7 +623,7 @@ static void timekeeping_forward_now(stru
> {
> struct clocksource *clock = tk->tkr_mono.clock;
> cycle_t cycle_now, delta;
> - s64 nsec;
> + u64 nsec;
>
> cycle_now = tk->tkr_mono.read(clock);
> delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
> @@ -652,7 +652,7 @@ int __getnstimeofday64(struct timespec64
> {
> struct timekeeper *tk = &tk_core.timekeeper;
> unsigned long seq;
> - s64 nsecs = 0;
> + u64 nsecs;
>
> do {
> seq = read_seqcount_begin(&tk_core.seq);
> @@ -692,7 +692,7 @@ ktime_t ktime_get(void)
> struct timekeeper *tk = &tk_core.timekeeper;
> unsigned int seq;
> ktime_t base;
> - s64 nsecs;
> + u64 nsecs;
>
> WARN_ON(timekeeping_suspended);
>
> @@ -735,7 +735,7 @@ ktime_t ktime_get_with_offset(enum tk_of
> struct timekeeper *tk = &tk_core.timekeeper;
> unsigned int seq;
> ktime_t base, *offset = offsets[offs];
> - s64 nsecs;
> + u64 nsecs;
>
> WARN_ON(timekeeping_suspended);
>
> @@ -779,7 +779,7 @@ ktime_t ktime_get_raw(void)
> struct timekeeper *tk = &tk_core.timekeeper;
> unsigned int seq;
> ktime_t base;
> - s64 nsecs;
> + u64 nsecs;
>
> do {
> seq = read_seqcount_begin(&tk_core.seq);
> @@ -804,8 +804,8 @@ void ktime_get_ts64(struct timespec64 *t
> {
> struct timekeeper *tk = &tk_core.timekeeper;
> struct timespec64 tomono;
> - s64 nsec;
> unsigned int seq;
> + u64 nsec;
>
> WARN_ON(timekeeping_suspended);
>
> @@ -893,8 +893,8 @@ void ktime_get_snapshot(struct system_ti
> unsigned long seq;
> ktime_t base_raw;
> ktime_t base_real;
> - s64 nsec_raw;
> - s64 nsec_real;
> + u64 nsec_raw;
> + u64 nsec_real;
> cycle_t now;
>
> WARN_ON_ONCE(timekeeping_suspended);
> @@ -1052,7 +1052,7 @@ int get_device_system_crosststamp(int (*
> cycle_t cycles, now, interval_start;
> unsigned int clock_was_set_seq = 0;
> ktime_t base_real, base_raw;
> - s64 nsec_real, nsec_raw;
> + u64 nsec_real, nsec_raw;
> u8 cs_was_changed_seq;
> unsigned long seq;
> bool do_interp;
> @@ -1365,7 +1365,7 @@ void getrawmonotonic64(struct timespec64
> struct timekeeper *tk = &tk_core.timekeeper;
> struct timespec64 ts64;
> unsigned long seq;
> - s64 nsecs;
> + u64 nsecs;
>
> do {
> seq = read_seqcount_begin(&tk_core.seq);
>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2016-12-08 23:47 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 20:49 [patch 0/6] timekeeping: Cure the signed/unsigned wreckage Thomas Gleixner
2016-12-08 20:49 ` [patch 1/6] timekeeping: Force unsigned clocksource to nanoseconds conversion Thomas Gleixner
2016-12-08 23:38 ` David Gibson
2016-12-09 11:13 ` [tip:timers/core] timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 2/6] timekeeping: Make the conversion call chain consistently unsigned Thomas Gleixner
2016-12-08 23:39 ` David Gibson [this message]
2016-12-09 11:13 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 3/6] timekeeping: Get rid of pointless typecasts Thomas Gleixner
2016-12-08 23:40 ` David Gibson
2016-12-09 11:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 4/6] timekeeping: Use mul_u64_u32_shr() instead of open coding it Thomas Gleixner
2016-12-08 23:41 ` David Gibson
2016-12-09 11:14 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 5/6] [RFD] timekeeping: Provide optional 128bit math Thomas Gleixner
2016-12-09 4:08 ` Ingo Molnar
2016-12-09 4:29 ` Ingo Molnar
2016-12-09 4:39 ` John Stultz
2016-12-09 4:48 ` Peter Zijlstra
2016-12-09 5:22 ` Ingo Molnar
2016-12-09 5:41 ` Peter Zijlstra
2016-12-09 5:11 ` Peter Zijlstra
2016-12-09 6:08 ` Peter Zijlstra
2016-12-09 5:26 ` Peter Zijlstra
2016-12-09 6:38 ` Peter Zijlstra
2016-12-09 8:30 ` Peter Zijlstra
2016-12-09 9:11 ` Peter Zijlstra
2016-12-09 10:01 ` Peter Zijlstra
2016-12-09 17:32 ` Chris Metcalf
2017-01-14 12:51 ` [tip:timers/core] math64, timers: Fix 32bit mul_u64_u32_shr() and friends tip-bot for Peter Zijlstra
2016-12-09 10:18 ` [patch 5/6] [RFD] timekeeping: Provide optional 128bit math Peter Zijlstra
2016-12-09 17:20 ` Chris Metcalf
2016-12-08 20:49 ` [patch 6/6] [RFD] timekeeping: Get rid of cycle_t Thomas Gleixner
2016-12-08 23:43 ` David Gibson
2016-12-09 4:52 ` [patch 0/6] timekeeping: Cure the signed/unsigned wreckage John Stultz
2016-12-09 5:30 ` Peter Zijlstra
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