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authorThomas Gleixner <tglx@linutronix.de>2014-06-22 12:06:40 +0200
committerThomas Gleixner <tglx@linutronix.de>2014-06-23 11:22:35 +0200
commit5cee964597260237dd2cabb3ec22bba0da24b25d (patch)
treef548efb4181a4cffb026adf43178e65330533e87 /kernel/time.c
parentclocksource: Add a Kconfig menu (diff)
downloadlinux-dev-5cee964597260237dd2cabb3ec22bba0da24b25d.tar.xz
linux-dev-5cee964597260237dd2cabb3ec22bba0da24b25d.zip
time/timers: Move all time(r) related files into kernel/time
Except for Kconfig.HZ. That needs a separate treatment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time.c')
-rw-r--r--kernel/time.c714
1 files changed, 0 insertions, 714 deletions
diff --git a/kernel/time.c b/kernel/time.c
deleted file mode 100644
index 7c7964c33ae7..000000000000
--- a/kernel/time.c
+++ /dev/null
@@ -1,714 +0,0 @@
-/*
- * linux/kernel/time.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- *
- * This file contains the interface functions for the various
- * time related system calls: time, stime, gettimeofday, settimeofday,
- * adjtime
- */
-/*
- * Modification history kernel/time.c
- *
- * 1993-09-02 Philip Gladstone
- * Created file with time related functions from sched/core.c and adjtimex()
- * 1993-10-08 Torsten Duwe
- * adjtime interface update and CMOS clock write code
- * 1995-08-13 Torsten Duwe
- * kernel PLL updated to 1994-12-13 specs (rfc-1589)
- * 1999-01-16 Ulrich Windl
- * Introduced error checking for many cases in adjtimex().
- * Updated NTP code according to technical memorandum Jan '96
- * "A Kernel Model for Precision Timekeeping" by Dave Mills
- * Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10)
- * (Even though the technical memorandum forbids it)
- * 2004-07-14 Christoph Lameter
- * Added getnstimeofday to allow the posix timer functions to return
- * with nanosecond accuracy
- */
-
-#include <linux/export.h>
-#include <linux/timex.h>
-#include <linux/capability.h>
-#include <linux/timekeeper_internal.h>
-#include <linux/errno.h>
-#include <linux/syscalls.h>
-#include <linux/security.h>
-#include <linux/fs.h>
-#include <linux/math64.h>
-#include <linux/ptrace.h>
-
-#include <asm/uaccess.h>
-#include <asm/unistd.h>
-
-#include "timeconst.h"
-
-/*
- * The timezone where the local system is located. Used as a default by some
- * programs who obtain this value by using gettimeofday.
- */
-struct timezone sys_tz;
-
-EXPORT_SYMBOL(sys_tz);
-
-#ifdef __ARCH_WANT_SYS_TIME
-
-/*
- * sys_time() can be implemented in user-level using
- * sys_gettimeofday(). Is this for backwards compatibility? If so,
- * why not move it into the appropriate arch directory (for those
- * architectures that need it).
- */
-SYSCALL_DEFINE1(time, time_t __user *, tloc)
-{
- time_t i = get_seconds();
-
- if (tloc) {
- if (put_user(i,tloc))
- return -EFAULT;
- }
- force_successful_syscall_return();
- return i;
-}
-
-/*
- * sys_stime() can be implemented in user-level using
- * sys_settimeofday(). Is this for backwards compatibility? If so,
- * why not move it into the appropriate arch directory (for those
- * architectures that need it).
- */
-
-SYSCALL_DEFINE1(stime, time_t __user *, tptr)
-{
- struct timespec tv;
- int err;
-
- if (get_user(tv.tv_sec, tptr))
- return -EFAULT;
-
- tv.tv_nsec = 0;
-
- err = security_settime(&tv, NULL);
- if (err)
- return err;
-
- do_settimeofday(&tv);
- return 0;
-}
-
-#endif /* __ARCH_WANT_SYS_TIME */
-
-SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
- struct timezone __user *, tz)
-{
- if (likely(tv != NULL)) {
- struct timeval ktv;
- do_gettimeofday(&ktv);
- if (copy_to_user(tv, &ktv, sizeof(ktv)))
- return -EFAULT;
- }
- if (unlikely(tz != NULL)) {
- if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
- return -EFAULT;
- }
- return 0;
-}
-
-/*
- * Indicates if there is an offset between the system clock and the hardware
- * clock/persistent clock/rtc.
- */
-int persistent_clock_is_local;
-
-/*
- * Adjust the time obtained from the CMOS to be UTC time instead of
- * local time.
- *
- * This is ugly, but preferable to the alternatives. Otherwise we
- * would either need to write a program to do it in /etc/rc (and risk
- * confusion if the program gets run more than once; it would also be
- * hard to make the program warp the clock precisely n hours) or
- * compile in the timezone information into the kernel. Bad, bad....
- *
- * - TYT, 1992-01-01
- *
- * The best thing to do is to keep the CMOS clock in universal time (UTC)
- * as real UNIX machines always do it. This avoids all headaches about
- * daylight saving times and warping kernel clocks.
- */
-static inline void warp_clock(void)
-{
- if (sys_tz.tz_minuteswest != 0) {
- struct timespec adjust;
-
- persistent_clock_is_local = 1;
- adjust.tv_sec = sys_tz.tz_minuteswest * 60;
- adjust.tv_nsec = 0;
- timekeeping_inject_offset(&adjust);
- }
-}
-
-/*
- * In case for some reason the CMOS clock has not already been running
- * in UTC, but in some local time: The first time we set the timezone,
- * we will warp the clock so that it is ticking UTC time instead of
- * local time. Presumably, if someone is setting the timezone then we
- * are running in an environment where the programs understand about
- * timezones. This should be done at boot time in the /etc/rc script,
- * as soon as possible, so that the clock can be set right. Otherwise,
- * various programs will get confused when the clock gets warped.
- */
-
-int do_sys_settimeofday(const struct timespec *tv, const struct timezone *tz)
-{
- static int firsttime = 1;
- int error = 0;
-
- if (tv && !timespec_valid(tv))
- return -EINVAL;
-
- error = security_settime(tv, tz);
- if (error)
- return error;
-
- if (tz) {
- sys_tz = *tz;
- update_vsyscall_tz();
- if (firsttime) {
- firsttime = 0;
- if (!tv)
- warp_clock();
- }
- }
- if (tv)
- return do_settimeofday(tv);
- return 0;
-}
-
-SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
- struct timezone __user *, tz)
-{
- struct timeval user_tv;
- struct timespec new_ts;
- struct timezone new_tz;
-
- if (tv) {
- if (copy_from_user(&user_tv, tv, sizeof(*tv)))
- return -EFAULT;
- new_ts.tv_sec = user_tv.tv_sec;
- new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
- }
- if (tz) {
- if (copy_from_user(&new_tz, tz, sizeof(*tz)))
- return -EFAULT;
- }
-
- return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
-}
-
-SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
-{
- struct timex txc; /* Local copy of parameter */
- int ret;
-
- /* Copy the user data space into the kernel copy
- * structure. But bear in mind that the structures
- * may change
- */
- if(copy_from_user(&txc, txc_p, sizeof(struct timex)))
- return -EFAULT;
- ret = do_adjtimex(&txc);
- return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
-}
-
-/**
- * current_fs_time - Return FS time
- * @sb: Superblock.
- *
- * Return the current time truncated to the time granularity supported by
- * the fs.
- */
-struct timespec current_fs_time(struct super_block *sb)
-{
- struct timespec now = current_kernel_time();
- return timespec_trunc(now, sb->s_time_gran);
-}
-EXPORT_SYMBOL(current_fs_time);
-
-/*
- * Convert jiffies to milliseconds and back.
- *
- * Avoid unnecessary multiplications/divisions in the
- * two most common HZ cases:
- */
-unsigned int jiffies_to_msecs(const unsigned long j)
-{
-#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
- return (MSEC_PER_SEC / HZ) * j;
-#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
- return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
-#else
-# if BITS_PER_LONG == 32
- return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
-# else
- return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
-# endif
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_msecs);
-
-unsigned int jiffies_to_usecs(const unsigned long j)
-{
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
- return (USEC_PER_SEC / HZ) * j;
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
- return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
-#else
-# if BITS_PER_LONG == 32
- return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
-# else
- return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
-# endif
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_usecs);
-
-/**
- * timespec_trunc - Truncate timespec to a granularity
- * @t: Timespec
- * @gran: Granularity in ns.
- *
- * Truncate a timespec to a granularity. gran must be smaller than a second.
- * Always rounds down.
- *
- * This function should be only used for timestamps returned by
- * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because
- * it doesn't handle the better resolution of the latter.
- */
-struct timespec timespec_trunc(struct timespec t, unsigned gran)
-{
- /*
- * Division is pretty slow so avoid it for common cases.
- * Currently current_kernel_time() never returns better than
- * jiffies resolution. Exploit that.
- */
- if (gran <= jiffies_to_usecs(1) * 1000) {
- /* nothing */
- } else if (gran == 1000000000) {
- t.tv_nsec = 0;
- } else {
- t.tv_nsec -= t.tv_nsec % gran;
- }
- return t;
-}
-EXPORT_SYMBOL(timespec_trunc);
-
-/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
- * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
- * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
- *
- * [For the Julian calendar (which was used in Russia before 1917,
- * Britain & colonies before 1752, anywhere else before 1582,
- * and is still in use by some communities) leave out the
- * -year/100+year/400 terms, and add 10.]
- *
- * This algorithm was first published by Gauss (I think).
- *
- * WARNING: this function will overflow on 2106-02-07 06:28:16 on
- * machines where long is 32-bit! (However, as time_t is signed, we
- * will already get problems at other places on 2038-01-19 03:14:08)
- */
-unsigned long
-mktime(const unsigned int year0, const unsigned int mon0,
- const unsigned int day, const unsigned int hour,
- const unsigned int min, const unsigned int sec)
-{
- unsigned int mon = mon0, year = year0;
-
- /* 1..12 -> 11,12,1..10 */
- if (0 >= (int) (mon -= 2)) {
- mon += 12; /* Puts Feb last since it has leap day */
- year -= 1;
- }
-
- return ((((unsigned long)
- (year/4 - year/100 + year/400 + 367*mon/12 + day) +
- year*365 - 719499
- )*24 + hour /* now have hours */
- )*60 + min /* now have minutes */
- )*60 + sec; /* finally seconds */
-}
-
-EXPORT_SYMBOL(mktime);
-
-/**
- * set_normalized_timespec - set timespec sec and nsec parts and normalize
- *
- * @ts: pointer to timespec variable to be set
- * @sec: seconds to set
- * @nsec: nanoseconds to set
- *
- * Set seconds and nanoseconds field of a timespec variable and
- * normalize to the timespec storage format
- *
- * Note: The tv_nsec part is always in the range of
- * 0 <= tv_nsec < NSEC_PER_SEC
- * For negative values only the tv_sec field is negative !
- */
-void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec)
-{
- while (nsec >= NSEC_PER_SEC) {
- /*
- * The following asm() prevents the compiler from
- * optimising this loop into a modulo operation. See
- * also __iter_div_u64_rem() in include/linux/time.h
- */
- asm("" : "+rm"(nsec));
- nsec -= NSEC_PER_SEC;
- ++sec;
- }
- while (nsec < 0) {
- asm("" : "+rm"(nsec));
- nsec += NSEC_PER_SEC;
- --sec;
- }
- ts->tv_sec = sec;
- ts->tv_nsec = nsec;
-}
-EXPORT_SYMBOL(set_normalized_timespec);
-
-/**
- * ns_to_timespec - Convert nanoseconds to timespec
- * @nsec: the nanoseconds value to be converted
- *
- * Returns the timespec representation of the nsec parameter.
- */
-struct timespec ns_to_timespec(const s64 nsec)
-{
- struct timespec ts;
- s32 rem;
-
- if (!nsec)
- return (struct timespec) {0, 0};
-
- ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
- if (unlikely(rem < 0)) {
- ts.tv_sec--;
- rem += NSEC_PER_SEC;
- }
- ts.tv_nsec = rem;
-
- return ts;
-}
-EXPORT_SYMBOL(ns_to_timespec);
-
-/**
- * ns_to_timeval - Convert nanoseconds to timeval
- * @nsec: the nanoseconds value to be converted
- *
- * Returns the timeval representation of the nsec parameter.
- */
-struct timeval ns_to_timeval(const s64 nsec)
-{
- struct timespec ts = ns_to_timespec(nsec);
- struct timeval tv;
-
- tv.tv_sec = ts.tv_sec;
- tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000;
-
- return tv;
-}
-EXPORT_SYMBOL(ns_to_timeval);
-
-/*
- * When we convert to jiffies then we interpret incoming values
- * the following way:
- *
- * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
- *
- * - 'too large' values [that would result in larger than
- * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
- *
- * - all other values are converted to jiffies by either multiplying
- * the input value by a factor or dividing it with a factor
- *
- * We must also be careful about 32-bit overflows.
- */
-unsigned long msecs_to_jiffies(const unsigned int m)
-{
- /*
- * Negative value, means infinite timeout:
- */
- if ((int)m < 0)
- return MAX_JIFFY_OFFSET;
-
-#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
- /*
- * HZ is equal to or smaller than 1000, and 1000 is a nice
- * round multiple of HZ, divide with the factor between them,
- * but round upwards:
- */
- return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);
-#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
- /*
- * HZ is larger than 1000, and HZ is a nice round multiple of
- * 1000 - simply multiply with the factor between them.
- *
- * But first make sure the multiplication result cannot
- * overflow:
- */
- if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
- return MAX_JIFFY_OFFSET;
-
- return m * (HZ / MSEC_PER_SEC);
-#else
- /*
- * Generic case - multiply, round and divide. But first
- * check that if we are doing a net multiplication, that
- * we wouldn't overflow:
- */
- if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
- return MAX_JIFFY_OFFSET;
-
- return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
- >> MSEC_TO_HZ_SHR32;
-#endif
-}
-EXPORT_SYMBOL(msecs_to_jiffies);
-
-unsigned long usecs_to_jiffies(const unsigned int u)
-{
- if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
- return MAX_JIFFY_OFFSET;
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
- return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
- return u * (HZ / USEC_PER_SEC);
-#else
- return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
- >> USEC_TO_HZ_SHR32;
-#endif
-}
-EXPORT_SYMBOL(usecs_to_jiffies);
-
-/*
- * The TICK_NSEC - 1 rounds up the value to the next resolution. Note
- * that a remainder subtract here would not do the right thing as the
- * resolution values don't fall on second boundries. I.e. the line:
- * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
- *
- * Rather, we just shift the bits off the right.
- *
- * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
- * value to a scaled second value.
- */
-unsigned long
-timespec_to_jiffies(const struct timespec *value)
-{
- unsigned long sec = value->tv_sec;
- long nsec = value->tv_nsec + TICK_NSEC - 1;
-
- if (sec >= MAX_SEC_IN_JIFFIES){
- sec = MAX_SEC_IN_JIFFIES;
- nsec = 0;
- }
- return (((u64)sec * SEC_CONVERSION) +
- (((u64)nsec * NSEC_CONVERSION) >>
- (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
-
-}
-EXPORT_SYMBOL(timespec_to_jiffies);
-
-void
-jiffies_to_timespec(const unsigned long jiffies, struct timespec *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_nsec = rem;
-}
-EXPORT_SYMBOL(jiffies_to_timespec);
-
-/* Same for "timeval"
- *
- * Well, almost. The problem here is that the real system resolution is
- * in nanoseconds and the value being converted is in micro seconds.
- * Also for some machines (those that use HZ = 1024, in-particular),
- * there is a LARGE error in the tick size in microseconds.
-
- * The solution we use is to do the rounding AFTER we convert the
- * microsecond part. Thus the USEC_ROUND, the bits to be shifted off.
- * Instruction wise, this should cost only an additional add with carry
- * instruction above the way it was done above.
- */
-unsigned long
-timeval_to_jiffies(const struct timeval *value)
-{
- unsigned long sec = value->tv_sec;
- long usec = value->tv_usec;
-
- if (sec >= MAX_SEC_IN_JIFFIES){
- sec = MAX_SEC_IN_JIFFIES;
- usec = 0;
- }
- return (((u64)sec * SEC_CONVERSION) +
- (((u64)usec * USEC_CONVERSION + USEC_ROUND) >>
- (USEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
-}
-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.
- */
-clock_t jiffies_to_clock_t(unsigned long x)
-{
-#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
-# if HZ < USER_HZ
- return x * (USER_HZ / HZ);
-# else
- return x / (HZ / USER_HZ);
-# endif
-#else
- return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
-#endif
-}
-EXPORT_SYMBOL(jiffies_to_clock_t);
-
-unsigned long clock_t_to_jiffies(unsigned long x)
-{
-#if (HZ % USER_HZ)==0
- if (x >= ~0UL / (HZ / USER_HZ))
- return ~0UL;
- return x * (HZ / USER_HZ);
-#else
- /* Don't worry about loss of precision here .. */
- if (x >= ~0UL / HZ * USER_HZ)
- return ~0UL;
-
- /* .. but do try to contain it here */
- return div_u64((u64)x * HZ, USER_HZ);
-#endif
-}
-EXPORT_SYMBOL(clock_t_to_jiffies);
-
-u64 jiffies_64_to_clock_t(u64 x)
-{
-#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
-# if HZ < USER_HZ
- x = div_u64(x * USER_HZ, HZ);
-# elif HZ > USER_HZ
- x = div_u64(x, HZ / USER_HZ);
-# else
- /* Nothing to do */
-# endif
-#else
- /*
- * There are better ways that don't overflow early,
- * but even this doesn't overflow in hundreds of years
- * in 64 bits, so..
- */
- x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
-#endif
- return x;
-}
-EXPORT_SYMBOL(jiffies_64_to_clock_t);
-
-u64 nsec_to_clock_t(u64 x)
-{
-#if (NSEC_PER_SEC % USER_HZ) == 0
- return div_u64(x, NSEC_PER_SEC / USER_HZ);
-#elif (USER_HZ % 512) == 0
- return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
-#else
- /*
- * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
- * overflow after 64.99 years.
- * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
- */
- return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
-#endif
-}
-
-/**
- * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
- *
- * @n: nsecs in u64
- *
- * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
- * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
- * for scheduler, not for use in device drivers to calculate timeout value.
- *
- * note:
- * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
- * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
- */
-u64 nsecs_to_jiffies64(u64 n)
-{
-#if (NSEC_PER_SEC % HZ) == 0
- /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
- return div_u64(n, NSEC_PER_SEC / HZ);
-#elif (HZ % 512) == 0
- /* overflow after 292 years if HZ = 1024 */
- return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
-#else
- /*
- * Generic case - optimized for cases where HZ is a multiple of 3.
- * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
- */
- return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
-#endif
-}
-
-/**
- * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
- *
- * @n: nsecs in u64
- *
- * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
- * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
- * for scheduler, not for use in device drivers to calculate timeout value.
- *
- * note:
- * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
- * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
- */
-unsigned long nsecs_to_jiffies(u64 n)
-{
- return (unsigned long)nsecs_to_jiffies64(n);
-}
-
-/*
- * Add two timespec values and do a safety check for overflow.
- * It's assumed that both values are valid (>= 0)
- */
-struct timespec timespec_add_safe(const struct timespec lhs,
- const struct timespec rhs)
-{
- struct timespec res;
-
- set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec,
- lhs.tv_nsec + rhs.tv_nsec);
-
- if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
- res.tv_sec = TIME_T_MAX;
-
- return res;
-}