diff options
| -rw-r--r-- | include/linux/ktime.h | 27 | ||||
| -rw-r--r-- | 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 */ |