diff options
| -rw-r--r-- | include/linux/kernel.h | 9 | ||||
| -rw-r--r-- | lib/int_sqrt.c | 30 |
2 files changed, 39 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; diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c index e2d329099bf7..14436f4ca6bd 100644 --- a/lib/int_sqrt.c +++ b/lib/int_sqrt.c @@ -38,3 +38,33 @@ unsigned long int_sqrt(unsigned long x) return y; } EXPORT_SYMBOL(int_sqrt); + +#if BITS_PER_LONG < 64 +/** + * int_sqrt64 - strongly typed int_sqrt function when minimum 64 bit input + * is expected. + * @x: 64bit integer of which to calculate the sqrt + */ +u32 int_sqrt64(u64 x) +{ + u64 b, m, y = 0; + + if (x <= ULONG_MAX) + return int_sqrt((unsigned long) x); + + m = 1ULL << (fls64(x) & ~1ULL); + while (m != 0) { + b = y + m; + y >>= 1; + + if (x >= b) { + x -= b; + y += m; + } + m >>= 2; + } + + return y; +} +EXPORT_SYMBOL(int_sqrt64); +#endif |