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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2008-06-12 10:47:58 +0200
committerIngo Molnar <mingo@elte.hu>2008-06-12 10:47:58 +0200
commitd5e181f78ac753893eb930868a52a4488cd3de0a (patch)
tree7d2f71fd3c84196f0d81a9e44861743b74e58ef6 /include/linux/math64.h
parentf595ec964daf7f99668039d7303ddedd09a75142 (diff)
add an inlined version of iter_div_u64_rem
iter_div_u64_rem is used in the x86-64 vdso, which cannot call other kernel code. For this case, provide the always_inlined version, __iter_div_u64_rem. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/math64.h')
-rw-r--r--include/linux/math64.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 177785e1e4a3..c87f1528703a 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -83,4 +83,23 @@ static inline s64 div_s64(s64 dividend, s32 divisor)
u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
+static __always_inline u32
+__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
+{
+ u32 ret = 0;
+
+ while (dividend >= divisor) {
+ /* The following asm() prevents the compiler from
+ optimising this loop into a modulo operation. */
+ asm("" : "+rm"(dividend));
+
+ dividend -= divisor;
+ ret++;
+ }
+
+ *remainder = dividend;
+
+ return ret;
+}
+
#endif /* _LINUX_MATH64_H */