linux-kernel - [PATCH v2 22/24] y2038: remove obsolete jiffies conversion functions

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Message-Id: <20191213205417.3871055-13-arnd@arndb.de>
Date:   Fri, 13 Dec 2019 21:53:50 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     y2038@...ts.linaro.org, linux-kernel@...r.kernel.org,
        John Stultz <john.stultz@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Arnd Bergmann <arnd@...db.de>, Stephen Boyd <sboyd@...nel.org>,
        Li RongQing <lirongqing@...du.com>,
        Zhang Yu <zhangyu31@...du.com>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        Christian Brauner <christian.brauner@...ntu.com>,
        Dmitry Safonov <0x7f454c46@...il.com>,
        zhengbin <zhengbin13@...wei.com>
Subject: [PATCH v2 22/24] y2038: remove obsolete jiffies conversion functions

Now that the last user of timespec_to_jiffies() is gone, these
can just be removed, everything else is using ktime_t or timespec64
already.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 include/linux/jiffies.h | 20 --------------
 kernel/time/time.c      | 58 ++++-------------------------------------
 2 files changed, 5 insertions(+), 73 deletions(-)

diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 1b6d31da7cbc..e3279ef24d28 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -422,26 +422,6 @@ static __always_inline unsigned long usecs_to_jiffies(const unsigned int u)
 extern unsigned long timespec64_to_jiffies(const struct timespec64 *value);
 extern void jiffies_to_timespec64(const unsigned long jiffies,
 				  struct timespec64 *value);
-static inline unsigned long timespec_to_jiffies(const struct timespec *value)
-{
-	struct timespec64 ts = timespec_to_timespec64(*value);
-
-	return timespec64_to_jiffies(&ts);
-}
-
-static inline void jiffies_to_timespec(const unsigned long jiffies,
-				       struct timespec *value)
-{
-	struct timespec64 ts;
-
-	jiffies_to_timespec64(jiffies, &ts);
-	*value = timespec64_to_timespec(ts);
-}
-
-extern unsigned long timeval_to_jiffies(const struct timeval *value);
-extern void jiffies_to_timeval(const unsigned long jiffies,
-			       struct timeval *value);
-
 extern clock_t jiffies_to_clock_t(unsigned long x);
 static inline clock_t jiffies_delta_to_clock_t(long delta)
 {
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 704ccd9451b0..cdd7386115ff 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -626,10 +626,12 @@ EXPORT_SYMBOL(__usecs_to_jiffies);
  * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
  * value to a scaled second value.
  */
-static unsigned long
-__timespec64_to_jiffies(u64 sec, long nsec)
+
+unsigned long
+timespec64_to_jiffies(const struct timespec64 *value)
 {
-	nsec = nsec + TICK_NSEC - 1;
+	u64 sec = value->tv_sec;
+	long nsec = value->tv_nsec + TICK_NSEC - 1;
 
 	if (sec >= MAX_SEC_IN_JIFFIES){
 		sec = MAX_SEC_IN_JIFFIES;
@@ -640,18 +642,6 @@ __timespec64_to_jiffies(u64 sec, long nsec)
 		 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
 
 }
-
-static unsigned long
-__timespec_to_jiffies(unsigned long sec, long nsec)
-{
-	return __timespec64_to_jiffies((u64)sec, nsec);
-}
-
-unsigned long
-timespec64_to_jiffies(const struct timespec64 *value)
-{
-	return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
-}
 EXPORT_SYMBOL(timespec64_to_jiffies);
 
 void
@@ -668,44 +658,6 @@ jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
 }
 EXPORT_SYMBOL(jiffies_to_timespec64);
 
-/*
- * We could use a similar algorithm to timespec_to_jiffies (with a
- * different multiplier for usec instead of nsec). But this has a
- * problem with rounding: we can't exactly add TICK_NSEC - 1 to the
- * usec value, since it's not necessarily integral.
- *
- * We could instead round in the intermediate scaled representation
- * (i.e. in units of 1/2^(large scale) jiffies) but that's also
- * perilous: the scaling introduces a small positive error, which
- * combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
- * units to the intermediate before shifting) leads to accidental
- * overflow and overestimates.
- *
- * At the cost of one additional multiplication by a constant, just
- * use the timespec implementation.
- */
-unsigned long
-timeval_to_jiffies(const struct timeval *value)
-{
-	return __timespec_to_jiffies(value->tv_sec,
-				     value->tv_usec * NSEC_PER_USEC);
-}
-EXPORT_SYMBOL(timeval_to_jiffies);
-
-void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
-{
-	/*
-	 * Convert jiffies to nanoseconds and separate with
-	 * one divide.
-	 */
-	u32 rem;
-
-	value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
-				    NSEC_PER_SEC, &rem);
-	value->tv_usec = rem / NSEC_PER_USEC;
-}
-EXPORT_SYMBOL(jiffies_to_timeval);
-
 /*
  * Convert jiffies/jiffies_64 to clock_t and back.
  */
-- 
2.20.0