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authorRoman Zippel <zippel@linux-m68k.org>2008-05-01 04:34:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-05-01 08:03:58 -0700
commit71abb3af62dfa52930755f3b6497eafbe1d6ec85 (patch)
tree8e37f74017b800127538f6620820ea90b53169b5 /kernel/time.c
parent2418f4f28f8467b92a6177af32d05737ebf6206c (diff)
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>
Diffstat (limited to 'kernel/time.c')
-rw-r--r--kernel/time.c29
1 files changed, 9 insertions, 20 deletions
diff --git a/kernel/time.c b/kernel/time.c
index 86729042e4c..343e2515375 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 @@ clock_t jiffies_to_clock_t(long x)
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 @@ unsigned long clock_t_to_jiffies(unsigned long x)
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 @@ u64 jiffies_64_to_clock_t(u64 x)
{
#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 @@ u64 jiffies_64_to_clock_t(u64 x)
* 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 @@ EXPORT_SYMBOL(jiffies_64_to_clock_t);
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)