convert a few do_div users
This converts a few users of do_div to div_[su]64 and this demonstrates nicely
how it can reduce some expressions to one-liners.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/time.c b/kernel/time.c
index 8672904..343e2515 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -36,6 +36,7 @@
#include <linux/security.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/math64.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -587,9 +588,7 @@
return x / (HZ / USER_HZ);
# endif
#else
- u64 tmp = (u64)x * TICK_NSEC;
- do_div(tmp, (NSEC_PER_SEC / USER_HZ));
- return (long)tmp;
+ return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
#endif
}
EXPORT_SYMBOL(jiffies_to_clock_t);
@@ -601,16 +600,12 @@
return ~0UL;
return x * (HZ / USER_HZ);
#else
- u64 jif;
-
/* Don't worry about loss of precision here .. */
if (x >= ~0UL / HZ * USER_HZ)
return ~0UL;
/* .. but do try to contain it here */
- jif = x * (u64) HZ;
- do_div(jif, USER_HZ);
- return jif;
+ return div_u64((u64)x * HZ, USER_HZ);
#endif
}
EXPORT_SYMBOL(clock_t_to_jiffies);
@@ -619,10 +614,9 @@
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
# if HZ < USER_HZ
- x *= USER_HZ;
- do_div(x, HZ);
+ x = div_u64(x * USER_HZ, HZ);
# elif HZ > USER_HZ
- do_div(x, HZ / USER_HZ);
+ x = div_u64(x, HZ / USER_HZ);
# else
/* Nothing to do */
# endif
@@ -632,8 +626,7 @@
* but even this doesn't overflow in hundreds of years
* in 64 bits, so..
*/
- x *= TICK_NSEC;
- do_div(x, (NSEC_PER_SEC / USER_HZ));
+ x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
#endif
return x;
}
@@ -642,21 +635,17 @@
u64 nsec_to_clock_t(u64 x)
{
#if (NSEC_PER_SEC % USER_HZ) == 0
- do_div(x, (NSEC_PER_SEC / USER_HZ));
+ return div_u64(x, NSEC_PER_SEC / USER_HZ);
#elif (USER_HZ % 512) == 0
- x *= USER_HZ/512;
- do_div(x, (NSEC_PER_SEC / 512));
+ return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
#else
/*
* max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
* overflow after 64.99 years.
* exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
*/
- x *= 9;
- do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2)) /
- USER_HZ));
+ return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
#endif
- return x;
}
#if (BITS_PER_LONG < 64)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5fd9b94..a4492f3 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -15,7 +15,7 @@
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/capability.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
#include <asm/timex.h>
/*
@@ -53,10 +53,8 @@
tick_length_base = second_length;
- do_div(second_length, HZ);
- tick_nsec = second_length >> TICK_LENGTH_SHIFT;
-
- do_div(tick_length_base, NTP_INTERVAL_FREQ);
+ tick_nsec = div_u64(second_length, HZ) >> TICK_LENGTH_SHIFT;
+ tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
}
/**
@@ -237,7 +235,7 @@
int do_adjtimex(struct timex *txc)
{
long mtemp, save_adjust, rem;
- s64 freq_adj, temp64;
+ s64 freq_adj;
int result;
/* In order to modify anything, you gotta be super-user! */
@@ -342,19 +340,8 @@
freq_adj = time_offset * mtemp;
freq_adj = shift_right(freq_adj, time_constant * 2 +
(SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
- if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
- u64 utemp64;
- temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
- if (time_offset < 0) {
- utemp64 = -temp64;
- do_div(utemp64, mtemp);
- freq_adj -= utemp64;
- } else {
- utemp64 = temp64;
- do_div(utemp64, mtemp);
- freq_adj += utemp64;
- }
- }
+ if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC))
+ freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp);
freq_adj += time_freq;
freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);