time: Move time_t conversion helpers to time32.h

On 64-bit architectures, the timespec64 based helpers in linux/time.h
are defined as macros pointing to their timespec based counterparts.
This made sense when they were first introduced, but as we are migrating
away from timespec in general, it's much less intuitive now.

This changes the macros to work in the exact opposite way: we always
provide the timespec64 based helpers and define the old interfaces as
macros for them. Now we can move those macros into linux/time32.h, which
already contains the respective helpers for 32-bit architectures.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

3 files changed, 49 insertions, 51 deletions

diff --git a/include/linux/time32.h b/include/linux/time32.h
index 9b9c43f0d39b..65b1de25198d 100644
--- a/include/linux/time32.h
+++ b/include/linux/time32.h
@@ -13,6 +13,49 @@
 
 #define TIME_T_MAX      (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
 
+#if __BITS_PER_LONG == 64
+
+/* timespec64 is defined as timespec here */
+static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
+{
+        return ts64;
+}
+
+static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
+{
+        return ts;
+}
+
+# define timespec_equal                 timespec64_equal
+# define timespec_compare               timespec64_compare
+# define set_normalized_timespec        set_normalized_timespec64
+# define timespec_add                   timespec64_add
+# define timespec_sub                   timespec64_sub
+# define timespec_valid                 timespec64_valid
+# define timespec_valid_strict          timespec64_valid_strict
+# define timespec_to_ns                 timespec64_to_ns
+# define ns_to_timespec                 ns_to_timespec64
+# define timespec_add_ns                timespec64_add_ns
+
+#else
+static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
+{
+        struct timespec ret;
+
+        ret.tv_sec = (time_t)ts64.tv_sec;
+        ret.tv_nsec = ts64.tv_nsec;
+        return ret;
+}
+
+static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
+{
+        struct timespec64 ret;
+
+        ret.tv_sec = ts.tv_sec;
+        ret.tv_nsec = ts.tv_nsec;
+        return ret;
+}
+
 static inline int timespec_equal(const struct timespec *a,
                                  const struct timespec *b)
 {
@@ -116,6 +159,8 @@ static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
         a->tv_nsec = ns;
 }
 
+#endif
+
 /**
  * time_to_tm - converts the calendar time to local broken-down time
  *
diff --git a/include/linux/time64.h b/include/linux/time64.h
index 402b595c76d2..ec1888cf5378 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -7,11 +7,8 @@
 typedef __s64 time64_t;
 typedef __u64 timeu64_t;
 
-/*
- * This wants to go into uapi/linux/time.h once we agreed about the
- * userspace interfaces.
- */
 #if __BITS_PER_LONG == 64
+/* this trick allows us to optimize out timespec64_to_timespec */
 # define timespec64 timespec
 #define itimerspec64 itimerspec
 #else
@@ -41,49 +38,6 @@ struct itimerspec64 {
 #define KTIME_MAX                       ((s64)~((u64)1 << 63))
 #define KTIME_SEC_MAX                   (KTIME_MAX / NSEC_PER_SEC)
 
-#if __BITS_PER_LONG == 64
-
-static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
-{
-        return ts64;
-}
-
-static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
-{
-        return ts;
-}
-
-# define timespec64_equal               timespec_equal
-# define timespec64_compare             timespec_compare
-# define set_normalized_timespec64      set_normalized_timespec
-# define timespec64_add                 timespec_add
-# define timespec64_sub                 timespec_sub
-# define timespec64_valid               timespec_valid
-# define timespec64_valid_strict        timespec_valid_strict
-# define timespec64_to_ns               timespec_to_ns
-# define ns_to_timespec64               ns_to_timespec
-# define timespec64_add_ns              timespec_add_ns
-
-#else
-
-static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64)
-{
-        struct timespec ret;
-
-        ret.tv_sec = (time_t)ts64.tv_sec;
-        ret.tv_nsec = ts64.tv_nsec;
-        return ret;
-}
-
-static inline struct timespec64 timespec_to_timespec64(const struct timespec ts)
-{
-        struct timespec64 ret;
-
-        ret.tv_sec = ts.tv_sec;
-        ret.tv_nsec = ts.tv_nsec;
-        return ret;
-}
-
 static inline int timespec64_equal(const struct timespec64 *a,
                                    const struct timespec64 *b)
 {
@@ -185,8 +139,6 @@ static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
         a->tv_nsec = ns;
 }
 
-#endif
-
 /*
  * timespec64_add_safe assumes both values are positive and checks for
  * overflow. It will return TIME64_MAX in case of overflow.
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 947fb614c78f..fe60ebd301cf 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -407,6 +407,7 @@ time64_t mktime64(const unsigned int year0, const unsigned int mon0,
 }
 EXPORT_SYMBOL(mktime64);
 
+#if __BITS_PER_LONG == 32
 /**
  * set_normalized_timespec - set timespec sec and nsec parts and normalize
  *
@@ -467,6 +468,7 @@ struct timespec ns_to_timespec(const s64 nsec)
         return ts;
 }
 EXPORT_SYMBOL(ns_to_timespec);
+#endif
 
 /**
  * ns_to_timeval - Convert nanoseconds to timeval
@@ -486,7 +488,6 @@ struct timeval ns_to_timeval(const s64 nsec)
 }
 EXPORT_SYMBOL(ns_to_timeval);
 
-#if BITS_PER_LONG == 32
 /**
  * set_normalized_timespec - set timespec sec and nsec parts and normalize
  *
@@ -547,7 +548,7 @@ struct timespec64 ns_to_timespec64(const s64 nsec)
         return ts;
 }
 EXPORT_SYMBOL(ns_to_timespec64);
-#endif
+
 /**
  * msecs_to_jiffies: - convert milliseconds to jiffies
  * @m:  time in milliseconds