select: add a timespec_add_safe() function
For the select() rework, it's important to be able to add timespec
structures in an overflow-safe manner.
This patch adds a timespec_add_safe() function for this which is similar in
operation to ktime_add_safe(), but works on a struct timespec.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
diff --git a/include/linux/time.h b/include/linux/time.h
index e15206a..7269764 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -38,6 +38,8 @@
#define NSEC_PER_SEC 1000000000L
#define FSEC_PER_SEC 1000000000000000L
+#define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+
static inline int timespec_equal(const struct timespec *a,
const struct timespec *b)
{
@@ -72,6 +74,8 @@
const unsigned int min, const unsigned int sec);
extern void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec);
+extern struct timespec timespec_add_safe(const struct timespec lhs,
+ const struct timespec rhs);
/*
* sub = lhs - rhs, in normalized form