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Merge branch 'core/iter-div' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'core/iter-div' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  always_inline timespec_add_ns
  add an inlined version of iter_div_u64_rem
  common implementation of iterative div/mod
This commit is contained in:
Linus Torvalds
2008-06-12 07:47:44 -07:00
parent 631025b4d8 9412e28649
commit dc10885d68
4 changed files with 40 additions and 20 deletions
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21
include/linux/math64.h
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@@ -81,4 +81,25 @@ static inline s64 div_s64(s64 dividend, s32 divisor)
}
#endif
u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
static __always_inline u32
__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
{
u32 ret = 0;
while (dividend >= divisor) {
/* The following asm() prevents the compiler from
optimising this loop into a modulo operation. */
asm("" : "+rm"(dividend));
dividend -= divisor;
ret++;
}
*remainder = dividend;
return ret;
}
#endif /* _LINUX_MATH64_H */

16
include/linux/time.h
View File

@@ -6,6 +6,7 @@
#ifdef __KERNEL__
# include <linux/cache.h>
# include <linux/seqlock.h>
# include <linux/math64.h>
#endif
#ifndef _STRUCT_TIMESPEC
@@ -169,18 +170,13 @@ extern struct timeval ns_to_timeval(const s64 nsec);
* timespec_add_ns - Adds nanoseconds to a timespec
* @a: pointer to timespec to be incremented
* @ns: unsigned nanoseconds value to be added
*
* This must always be inlined because its used from the x86-64 vdso,
* which cannot call other kernel functions.
*/
static inline void timespec_add_ns(struct timespec *a, u64 ns)
static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
{
ns += a->tv_nsec;
while(unlikely(ns >= NSEC_PER_SEC)) {
/* The following asm() prevents the compiler from
* optimising this loop into a modulo operation. */
asm("" : "+r"(ns));
ns -= NSEC_PER_SEC;
a->tv_sec++;
}
a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
a->tv_nsec = ns;
}
#endif /* __KERNEL__ */