diff options
| author | Crt Mori <cmo@melexis.com> | 2018-01-11 11:19:57 +0100 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2018-02-04 10:17:21 +0000 |
| commit | 47a361634821dc66cefbfa70b9d10a91269d7f7d (patch) | |
| tree | ceba4c0edea64792e26e4d1a2363b64e374fa5cd /include/linux/kernel.h | |
| parent | 213451076bd370e55a70ff07f6575b1451ba1a9f (diff) | |
| download | lwn-47a361634821dc66cefbfa70b9d10a91269d7f7d.tar.gz lwn-47a361634821dc66cefbfa70b9d10a91269d7f7d.zip | |
lib: Add strongly typed 64bit int_sqrt
There is no option to perform 64bit integer sqrt on 32bit platform.
Added stronger typed int_sqrt64 enables the 64bit calculations to
be performed on 32bit platforms. Using same algorithm as int_sqrt()
with strong typing provides enough precision also on 32bit platforms,
but it sacrifices some performance. In case values are smaller than
ULONG_MAX the standard int_sqrt is used for calculation to maximize the
performance due to more native calculations.
Signed-off-by: Crt Mori <cmo@melexis.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'include/linux/kernel.h')
| -rw-r--r-- | include/linux/kernel.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index ce51455e2adf..2da80e079d56 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -479,6 +479,15 @@ extern int func_ptr_is_kernel_text(void *ptr); unsigned long int_sqrt(unsigned long); +#if BITS_PER_LONG < 64 +u32 int_sqrt64(u64 x); +#else +static inline u32 int_sqrt64(u64 x) +{ + return (u32)int_sqrt(x); +} +#endif + extern void bust_spinlocks(int yes); extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ extern int panic_timeout; |