* [GIT pull] timer updates for 4.1
@ 2015-05-23 19:14 Thomas Gleixner
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From: Thomas Gleixner @ 2015-05-23 19:14 UTC (permalink / raw
To: Linus Torvalds; +Cc: Andrew Morton, LKML, Ingo Molnar, H. Peter Anvin
Linus,
please pull the latest timers-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus
One more fix from the timer departement:
- Handle division of negative nanosecond values proper on 32bit.
A recent cleanup wreckaged the sign handling of the dividend and
dropped the check for negative divisors.
Thanks,
tglx
------------------>
John Stultz (1):
ktime: Fix ktime_divns to do signed division
include/linux/ktime.h | 27 +++++++++++++++++++++------
kernel/time/hrtimer.c | 14 ++++++++------
2 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 5fc3d1083071..2b6a204bd8d4 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -166,19 +166,34 @@ static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
}
#if BITS_PER_LONG < 64
-extern u64 __ktime_divns(const ktime_t kt, s64 div);
-static inline u64 ktime_divns(const ktime_t kt, s64 div)
+extern s64 __ktime_divns(const ktime_t kt, s64 div);
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
{
+ /*
+ * Negative divisors could cause an inf loop,
+ * so bug out here.
+ */
+ BUG_ON(div < 0);
if (__builtin_constant_p(div) && !(div >> 32)) {
- u64 ns = kt.tv64;
- do_div(ns, div);
- return ns;
+ s64 ns = kt.tv64;
+ u64 tmp = ns < 0 ? -ns : ns;
+
+ do_div(tmp, div);
+ return ns < 0 ? -tmp : tmp;
} else {
return __ktime_divns(kt, div);
}
}
#else /* BITS_PER_LONG < 64 */
-# define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
+{
+ /*
+ * 32-bit implementation cannot handle negative divisors,
+ * so catch them on 64bit as well.
+ */
+ WARN_ON(div < 0);
+ return kt.tv64 / div;
+}
#endif
static inline s64 ktime_to_us(const ktime_t kt)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 76d4bd962b19..93ef7190bdea 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -266,21 +266,23 @@ lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
/*
* Divide a ktime value by a nanosecond value
*/
-u64 __ktime_divns(const ktime_t kt, s64 div)
+s64 __ktime_divns(const ktime_t kt, s64 div)
{
- u64 dclc;
int sft = 0;
+ s64 dclc;
+ u64 tmp;
dclc = ktime_to_ns(kt);
+ tmp = dclc < 0 ? -dclc : dclc;
+
/* Make sure the divisor is less than 2^32: */
while (div >> 32) {
sft++;
div >>= 1;
}
- dclc >>= sft;
- do_div(dclc, (unsigned long) div);
-
- return dclc;
+ tmp >>= sft;
+ do_div(tmp, (unsigned long) div);
+ return dclc < 0 ? -tmp : tmp;
}
EXPORT_SYMBOL_GPL(__ktime_divns);
#endif /* BITS_PER_LONG >= 64 */
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