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remove div_long_long_rem

Browse source 
x86 is the only arch right now, which provides an optimized for
div_long_long_rem and it has the downside that one has to be very careful that
the divide doesn't overflow.

The API is a little akward, as the arguments for the unsigned divide are
signed.  The signed version also doesn't handle a negative divisor and
produces worse code on 64bit archs.

There is little incentive to keep this API alive, so this converts the few
users to the new API.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Zippel 2008-05-01 04:34:31 -07:00 committed by Linus Torvalds
parent 6f6d6a1a6a
commit f8bd2258e2
10 changed files with 44 additions and 110 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
arch/mips/kernel/binfmt_elfn32.c
View file

@ -54,6 +54,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
#include <linux/module.h>
#include <linux/elfcore.h>
#include <linux/compat.h>
#include <linux/math64.h>
#define elf_prstatus elf_prstatus32
struct elf_prstatus32
@ -102,8 +103,8 @@ jiffies_to_compat_timeval(unsigned long jiffies, struct compat_timeval *value)
* one divide.
*/
u64 nsec = (u64)jiffies * TICK_NSEC;
long rem;
value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
u32 rem;
value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
value->tv_usec = rem / NSEC_PER_USEC;
}

5
arch/mips/kernel/binfmt_elfo32.c
View file

@ -56,6 +56,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
#include <linux/module.h>
#include <linux/elfcore.h>
#include <linux/compat.h>
#include <linux/math64.h>
#define elf_prstatus elf_prstatus32
struct elf_prstatus32
@ -104,8 +105,8 @@ jiffies_to_compat_timeval(unsigned long jiffies, struct compat_timeval *value)
* one divide.
*/
u64 nsec = (u64)jiffies * TICK_NSEC;
long rem;
value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
u32 rem;
value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
value->tv_usec = rem / NSEC_PER_USEC;
}

24
drivers/char/mmtimer.c
View file

@ -30,6 +30,8 @@
#include <linux/miscdevice.h>
#include <linux/posix-timers.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/math64.h>
#include <asm/uaccess.h>
#include <asm/sn/addrs.h>
@ -472,8 +474,8 @@ static int sgi_clock_get(clockid_t clockid, struct timespec *tp)
nsec = rtc_time() * sgi_clock_period
+ sgi_clock_offset.tv_nsec;
tp->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tp->tv_nsec)
+ sgi_clock_offset.tv_sec;
*tp = ns_to_timespec(nsec);
tp->tv_sec += sgi_clock_offset.tv_sec;
return 0;
};
@ -481,11 +483,11 @@ static int sgi_clock_set(clockid_t clockid, struct timespec *tp)
{
u64 nsec;
u64 rem;
u32 rem;
nsec = rtc_time() * sgi_clock_period;
sgi_clock_offset.tv_sec = tp->tv_sec - div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
if (rem <= tp->tv_nsec)
sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
@ -644,9 +646,6 @@ static int sgi_timer_del(struct k_itimer *timr)
return 0;
}
#define timespec_to_ns(x) ((x).tv_nsec + (x).tv_sec * NSEC_PER_SEC)
#define ns_to_timespec(ts, nsec) (ts).tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &(ts).tv_nsec)
/* Assumption: it_lock is already held with irq's disabled */
static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
{
@ -659,9 +658,8 @@ static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
return;
}
ns_to_timespec(cur_setting->it_interval, timr->it.mmtimer.incr * sgi_clock_period);
ns_to_timespec(cur_setting->it_value, (timr->it.mmtimer.expires - rtc_time())* sgi_clock_period);
return;
cur_setting->it_interval = ns_to_timespec(timr->it.mmtimer.incr * sgi_clock_period);
cur_setting->it_value = ns_to_timespec((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
}
@ -679,8 +677,8 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
sgi_timer_get(timr, old_setting);
sgi_timer_del(timr);
when = timespec_to_ns(new_setting->it_value);
period = timespec_to_ns(new_setting->it_interval);
when = timespec_to_ns(&new_setting->it_value);
period = timespec_to_ns(&new_setting->it_interval);
if (when == 0)
/* Clear timer */
@ -695,7 +693,7 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
unsigned long now;
getnstimeofday(&n);
now = timespec_to_ns(n);
now = timespec_to_ns(&n);
if (when > now)
when -= now;
else

18
include/asm-x86/div64.h
View file

@ -33,24 +33,6 @@
__mod; \
})
/*
* (long)X = ((long long)divs) / (long)div
* (long)rem = ((long long)divs) % (long)div
*
* Warning, this will do an exception if X overflows.
*/
#define div_long_long_rem(a, b, c) div_ll_X_l_rem(a, b, c)
static inline long div_ll_X_l_rem(long long divs, long div, long *rem)
{
long dum2;
asm("divl %2":"=a"(dum2), "=d"(*rem)
: "rm"(div), "A"(divs));
return dum2;
}
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
union {

49
include/linux/calc64.h
View file

@ -1,49 +0,0 @@
#ifndef _LINUX_CALC64_H
#define _LINUX_CALC64_H
#include <linux/types.h>
#include <asm/div64.h>
/*
* This is a generic macro which is used when the architecture
* specific div64.h does not provide a optimized one.
*
* The 64bit dividend is divided by the divisor (data type long), the
* result is returned and the remainder stored in the variable
* referenced by remainder (data type long *). In contrast to the
* do_div macro the dividend is kept intact.
*/
#ifndef div_long_long_rem
#define div_long_long_rem(dividend, divisor, remainder) \
do_div_llr((dividend), divisor, remainder)
static inline unsigned long do_div_llr(const long long dividend,
const long divisor, long *remainder)
{
u64 result = dividend;
*(remainder) = do_div(result, divisor);
return (unsigned long) result;
}
#endif
/*
* Sign aware variation of the above. On some architectures a
* negative dividend leads to an divide overflow exception, which
* is avoided by the sign check.
*/
static inline long div_long_long_rem_signed(const long long dividend,
const long divisor, long *remainder)
{
long res;
if (unlikely(dividend < 0)) {
res = -div_long_long_rem(-dividend, divisor, remainder);
*remainder = -(*remainder);
} else
res = div_long_long_rem(dividend, divisor, remainder);
return res;
}
#endif

2
include/linux/jiffies.h
View file

@ -1,7 +1,7 @@
#ifndef _LINUX_JIFFIES_H
#define _LINUX_JIFFIES_H
#include <linux/calc64.h>
#include <linux/math64.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/time.h>

11
kernel/posix-cpu-timers.c
View file

@ -4,8 +4,9 @@
#include <linux/sched.h>
#include <linux/posix-timers.h>
#include <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/math64.h>
#include <asm/uaccess.h>
static int check_clock(const clockid_t which_clock)
{
@ -47,12 +48,10 @@ static void sample_to_timespec(const clockid_t which_clock,
union cpu_time_count cpu,
struct timespec *tp)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
tp->tv_sec = div_long_long_rem(cpu.sched,
NSEC_PER_SEC, &tp->tv_nsec);
} else {
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
*tp = ns_to_timespec(cpu.sched);
else
cputime_to_timespec(cpu.cpu, tp);
}
}
static inline int cpu_time_before(const clockid_t which_clock,

25
kernel/time.c
View file

@ -392,13 +392,17 @@ EXPORT_SYMBOL(set_normalized_timespec);
struct timespec ns_to_timespec(const s64 nsec)
{
struct timespec ts;
s32 rem;
if (!nsec)
return (struct timespec) {0, 0};
ts.tv_sec = div_long_long_rem_signed(nsec, NSEC_PER_SEC, &ts.tv_nsec);
if (unlikely(nsec < 0))
set_normalized_timespec(&ts, ts.tv_sec, ts.tv_nsec);
ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
if (unlikely(rem < 0)) {
ts.tv_sec--;
rem += NSEC_PER_SEC;
}
ts.tv_nsec = rem;
return ts;
}
@ -528,8 +532,10 @@ jiffies_to_timespec(const unsigned long jiffies, struct timespec *value)
* Convert jiffies to nanoseconds and separate with
* one divide.
*/
u64 nsec = (u64)jiffies * TICK_NSEC;
value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec);
u32 rem;
value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
NSEC_PER_SEC, &rem);
value->tv_nsec = rem;
}
EXPORT_SYMBOL(jiffies_to_timespec);
@ -567,12 +573,11 @@ void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
* Convert jiffies to nanoseconds and separate with
* one divide.
*/
u64 nsec = (u64)jiffies * TICK_NSEC;
long tv_usec;
u32 rem;
value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tv_usec);
tv_usec /= NSEC_PER_USEC;
value->tv_usec = tv_usec;
value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
NSEC_PER_SEC, &rem);
value->tv_usec = rem / NSEC_PER_USEC;
}
EXPORT_SYMBOL(jiffies_to_timeval);

6
kernel/time/ntp.c
View file

@ -234,7 +234,7 @@ static inline void notify_cmos_timer(void) { }
*/
int do_adjtimex(struct timex *txc)
{
long mtemp, save_adjust, rem;
long mtemp, save_adjust;
s64 freq_adj;
int result;
@ -345,9 +345,7 @@ int do_adjtimex(struct timex *txc)
freq_adj += time_freq;
freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
time_offset = div_long_long_rem_signed(time_offset,
NTP_INTERVAL_FREQ,
&rem);
time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
time_offset <<= SHIFT_UPDATE;
} /* STA_PLL */
} /* txc->modes & ADJ_OFFSET */

9
mm/slub.c
View file

@ -22,6 +22,7 @@
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/memory.h>
#include <linux/math64.h>
/*
* Lock order:
@ -3621,12 +3622,10 @@ static int list_locations(struct kmem_cache *s, char *buf,
len += sprintf(buf + len, "<not-available>");
if (l->sum_time != l->min_time) {
unsigned long remainder;
len += sprintf(buf + len, " age=%ld/%ld/%ld",
l->min_time,
div_long_long_rem(l->sum_time, l->count, &remainder),
l->max_time);
l->min_time,
(long)div_u64(l->sum_time, l->count),
l->max_time);
} else
len += sprintf(buf + len, " age=%ld",
l->min_time);