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authorDeepa Dinamani <deepa.kernel@gmail.com>2016-05-20 03:09:02 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 05:12:14 +0300
commitbc2c53e5f1a2bae69ae50ce3a592633da7fcf6d9 (patch)
tree2b2b3c255a4c177ca93f8bb909fd91eb9eeaa86d /kernel/time
parent35e481761cdc688dbee0ef552a13f49af8eba6cc (diff)
downloadlinux-bc2c53e5f1a2bae69ae50ce3a592633da7fcf6d9.tar.xz
time: add missing implementation for timespec64_add_safe()
timespec64_add_safe() has been defined in time64.h for 64 bit systems. But, 32 bit systems only have an extern function prototype defined. Provide a definition for the above function. The function will be necessary as part of y2038 changes. struct timespec is not y2038 safe. All references to timespec will be replaced by struct timespec64. The function is meant to be a replacement for timespec_add_safe(). The implementation is similar to timespec_add_safe(). Link: http://lkml.kernel.org/r/1461947989-21926-2-git-send-email-deepa.kernel@gmail.com Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/time.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/kernel/time/time.c b/kernel/time/time.c
index a4064b612066..cb1f83eb5599 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -769,3 +769,28 @@ struct timespec timespec_add_safe(const struct timespec lhs,
return res;
}
+
+#if __BITS_PER_LONG != 64
+
+/*
+ * Add two timespec64 values and do a safety check for overflow.
+ * It's assumed that both values are valid (>= 0).
+ * And, each timespec64 is in normalized form.
+ */
+struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
+ const struct timespec64 rhs)
+{
+ struct timespec64 res;
+
+ set_normalized_timespec64(&res, lhs.tv_sec + rhs.tv_sec,
+ lhs.tv_nsec + rhs.tv_nsec);
+
+ if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
+ res.tv_sec = TIME64_MAX;
+ res.tv_nsec = 0;
+ }
+
+ return res;
+}
+
+#endif