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lib: Add strongly typed 64bit int_sqrt

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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>
This commit is contained in:
Crt Mori
2018-01-11 11:19:57 +01:00
committed by Jonathan Cameron
parent 213451076b
commit 47a3616348
2 changed files with 39 additions and 0 deletions
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9
include/linux/kernel.h
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@@ -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;