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Commit c5db6a3b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull timer fix from Thomas Gleixner:
 "One more fix from the timer departement:

    - Handle division of negative nanosecond values proper on 32bit.

      A recent cleanup wrecked the sign handling of the dividend and
      dropped the check for negative divisors"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ktime: Fix ktime_divns to do signed division
parents 9bd4459a f7bcb70e

include/linux/ktime.h

+21 −6
Original line number Diff line number Diff line
@@ -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)

kernel/time/hrtimer.c

+8 −6
Original line number Diff line number Diff line
@@ -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 */