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authorCrt Mori <cmo@melexis.com>2018-01-11 11:19:57 +0100
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2018-02-04 10:17:21 +0000
commit47a361634821dc66cefbfa70b9d10a91269d7f7d (patch)
treeceba4c0edea64792e26e4d1a2363b64e374fa5cd /include/linux/kernel.h
parent213451076bd370e55a70ff07f6575b1451ba1a9f (diff)
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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.h9
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;