diff options
| author | Salman Qazi <sqazi@google.com> | 2012-03-09 16:41:01 -0800 |
|---|---|---|
| committer | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-10-05 14:47:27 +0300 |
| commit | 9280bea5b78b6a619c78b63f8273f5ec2e9b8d62 (patch) | |
| tree | a6eb610d3bde4e636a24e442e081d9d2757af140 /include | |
| parent | c1f1992e69791d7bfc59b097491f560c97015a08 (diff) | |
sched/x86: Fix overflow in cyc2ns_offset
Artem: only left the 'mult_frac' addition from this patch,
as we need it in ubi.
Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20120310004027.19291.88460.stgit@dungbeetle.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kernel.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 46ac9a50528d..349180f93fa0 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -85,6 +85,19 @@ } \ ) +/* + * Multiplies an integer by a fraction, while avoiding unnecessary + * overflow or loss of precision. + */ +#define mult_frac(x, numer, denom)( \ +{ \ + typeof(x) quot = (x) / (denom); \ + typeof(x) rem = (x) % (denom); \ + (quot * (numer)) + ((rem * (numer)) / (denom)); \ +} \ +) + + #define _RET_IP_ (unsigned long)__builtin_return_address(0) #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) |