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-rw-r--r--include/linux/ktime.h29
1 files changed, 27 insertions, 2 deletions
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index c9d645ad98ff..039bbe5f59df 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -166,9 +166,34 @@ static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
}
#if BITS_PER_LONG < 64
-extern u64 ktime_divns(const ktime_t kt, s64 div);
+extern s64 __ktime_divns(const ktime_t kt, s64 div);
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
+{
+ /*
+ * Negative divisors could cause an inf loop,
+ * so bug out here.
+ */
+ BUG_ON(div < 0);
+ if (__builtin_constant_p(div) && !(div >> 32)) {
+ s64 ns = kt.tv64;
+ u64 tmp = ns < 0 ? -ns : ns;
+
+ do_div(tmp, div);
+ return ns < 0 ? -tmp : tmp;
+ } else {
+ return __ktime_divns(kt, div);
+ }
+}
#else /* BITS_PER_LONG < 64 */
-# define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
+{
+ /*
+ * 32-bit implementation cannot handle negative divisors,
+ * so catch them on 64bit as well.
+ */
+ WARN_ON(div < 0);
+ return kt.tv64 / div;
+}
#endif
static inline s64 ktime_to_us(const ktime_t kt)