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| author | Roman Zippel <zippel@linux-m68k.org> | 2008-05-01 04:34:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-05-01 08:03:58 -0700 |
| commit | 71abb3af62dfa52930755f3b6497eafbe1d6ec85 (patch) | |
| tree | 8e37f74017b800127538f6620820ea90b53169b5 /kernel/time.c | |
| parent | 2418f4f28f8467b92a6177af32d05737ebf6206c (diff) | |
| download | lwn-71abb3af62dfa52930755f3b6497eafbe1d6ec85.tar.gz lwn-71abb3af62dfa52930755f3b6497eafbe1d6ec85.zip | |
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.c | 29 |
1 files changed, 9 insertions, 20 deletions
diff --git a/kernel/time.c b/kernel/time.c index 86729042e4cd..343e2515375a 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) |