Add macro/function to subtract constant nanoseconds.
Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>
--- a/include/linux/ktime.h 2007-08-29 11:31:59.000000000 -0700
+++ b/include/linux/ktime.h 2007-08-29 11:41:19.000000000 -0700
@@ -102,6 +102,13 @@ static inline ktime_t ktime_set(const lo
#define ktime_add_ns(kt, nsval) \
({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
+/*
+ * Subtract a ktime_t variable and a scalar nanosecond value.
+ * res = kt - nsval:
+ */
+#define ktime_sub_ns(kt, nsval) \
+ ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
+
/* convert a timespec to ktime_t format: */
static inline ktime_t timespec_to_ktime(struct timespec ts)
{
@@ -200,6 +207,15 @@ static inline ktime_t ktime_add(const kt
extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
/**
+ * ktime_sub_ns - Subtract a scalar nanoseconds value to a ktime_t variable
+ * @kt: minuend
+ * @nsec: subtrahend in nanoseconds
+ *
+ * Returns the difference of @kt and @nsec in ktime_t format
+ */
+extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);
+
+/**
* timespec_to_ktime - convert a timespec to ktime_t format
* @ts: the timespec variable to convert
*
--- a/kernel/hrtimer.c 2007-08-29 11:31:59.000000000 -0700
+++ b/kernel/hrtimer.c 2007-08-29 11:41:19.000000000 -0700
@@ -277,6 +277,30 @@ ktime_t ktime_add_ns(const ktime_t kt, u
}
EXPORT_SYMBOL_GPL(ktime_add_ns);
+
+/**
+ * ktime_sub_ns - Subract a scalar nanoseconds value to a ktime_t variable
+ * @kt: minuend
+ * @nsec: subtrahend in nanoseconds
+ *
+ * Returns the difference of kt and nsec in ktime_t format
+ */
+ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
+{
+ ktime_t tmp;
+
+ if (likely(nsec < NSEC_PER_SEC)) {
+ tmp.tv64 = nsec;
+ } else {
+ unsigned long rem = do_div(nsec, NSEC_PER_SEC);
+
+ tmp = ktime_set((long)nsec, rem);
+ }
+
+ return ktime_sub(kt, tmp);
+}
+
+EXPORT_SYMBOL_GPL(ktime_add_ns);
# endif /* !CONFIG_KTIME_SCALAR */
/*
--
Stephen Hemminger <[EMAIL PROTECTED]>
-
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