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When building the htmldocs (in verbose mode), scripts/kernel-doc reports the following type of warnings: Warning(include/linux/ktime.h:75): No description found for return value of 'ktime_set' Fix them by using a "Return:" section to describe the return values. (Also apply some minor reformatting along the way.) Signed-off-by: Yacine Belkadi <yacine.belkadi.1@gmail.com> Acked-by: Rob Landley <rob@landley.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
390 lines
10 KiB
C
390 lines
10 KiB
C
/*
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* include/linux/ktime.h
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*
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* ktime_t - nanosecond-resolution time format.
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*
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* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
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*
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* data type definitions, declarations, prototypes and macros.
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*
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* Started by: Thomas Gleixner and Ingo Molnar
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*
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* Credits:
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*
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* Roman Zippel provided the ideas and primary code snippets of
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* the ktime_t union and further simplifications of the original
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* code.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#ifndef _LINUX_KTIME_H
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#define _LINUX_KTIME_H
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#include <linux/time.h>
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#include <linux/jiffies.h>
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/*
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* ktime_t:
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*
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* On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
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* internal representation of time values in scalar nanoseconds. The
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* design plays out best on 64-bit CPUs, where most conversions are
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* NOPs and most arithmetic ktime_t operations are plain arithmetic
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* operations.
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*
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* On 32-bit CPUs an optimized representation of the timespec structure
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* is used to avoid expensive conversions from and to timespecs. The
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* endian-aware order of the tv struct members is chosen to allow
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* mathematical operations on the tv64 member of the union too, which
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* for certain operations produces better code.
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*
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* For architectures with efficient support for 64/32-bit conversions the
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* plain scalar nanosecond based representation can be selected by the
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* config switch CONFIG_KTIME_SCALAR.
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*/
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union ktime {
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s64 tv64;
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#if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
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struct {
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# ifdef __BIG_ENDIAN
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s32 sec, nsec;
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# else
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s32 nsec, sec;
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# endif
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} tv;
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#endif
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};
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typedef union ktime ktime_t; /* Kill this */
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/*
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* ktime_t definitions when using the 64-bit scalar representation:
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*/
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#if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
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/**
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* ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
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* @secs: seconds to set
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* @nsecs: nanoseconds to set
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*
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* Return: The ktime_t representation of the value.
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*/
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static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
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{
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#if (BITS_PER_LONG == 64)
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if (unlikely(secs >= KTIME_SEC_MAX))
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return (ktime_t){ .tv64 = KTIME_MAX };
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#endif
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return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
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}
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/* Subtract two ktime_t variables. rem = lhs -rhs: */
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#define ktime_sub(lhs, rhs) \
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({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
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/* Add two ktime_t variables. res = lhs + rhs: */
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#define ktime_add(lhs, rhs) \
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({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
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/*
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* Add a ktime_t variable and a scalar nanosecond value.
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* res = kt + nsval:
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*/
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#define ktime_add_ns(kt, nsval) \
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({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
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/*
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* Subtract a scalar nanosecod from a ktime_t variable
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* res = kt - nsval:
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*/
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#define ktime_sub_ns(kt, nsval) \
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({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
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/* convert a timespec to ktime_t format: */
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static inline ktime_t timespec_to_ktime(struct timespec ts)
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{
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return ktime_set(ts.tv_sec, ts.tv_nsec);
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}
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/* convert a timeval to ktime_t format: */
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static inline ktime_t timeval_to_ktime(struct timeval tv)
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{
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return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
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}
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/* Map the ktime_t to timespec conversion to ns_to_timespec function */
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#define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
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/* Map the ktime_t to timeval conversion to ns_to_timeval function */
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#define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
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/* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
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#define ktime_to_ns(kt) ((kt).tv64)
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#else /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
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/*
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* Helper macros/inlines to get the ktime_t math right in the timespec
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* representation. The macros are sometimes ugly - their actual use is
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* pretty okay-ish, given the circumstances. We do all this for
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* performance reasons. The pure scalar nsec_t based code was nice and
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* simple, but created too many 64-bit / 32-bit conversions and divisions.
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*
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* Be especially aware that negative values are represented in a way
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* that the tv.sec field is negative and the tv.nsec field is greater
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* or equal to zero but less than nanoseconds per second. This is the
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* same representation which is used by timespecs.
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*
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* tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
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*/
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/* Set a ktime_t variable to a value in sec/nsec representation: */
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static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
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{
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return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
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}
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/**
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* ktime_sub - subtract two ktime_t variables
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* @lhs: minuend
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* @rhs: subtrahend
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*
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* Return: The remainder of the subtraction.
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*/
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static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
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{
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ktime_t res;
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res.tv64 = lhs.tv64 - rhs.tv64;
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if (res.tv.nsec < 0)
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res.tv.nsec += NSEC_PER_SEC;
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return res;
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}
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/**
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* ktime_add - add two ktime_t variables
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* @add1: addend1
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* @add2: addend2
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*
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* Return: The sum of @add1 and @add2.
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*/
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static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
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{
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ktime_t res;
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res.tv64 = add1.tv64 + add2.tv64;
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/*
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* performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
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* so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
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*
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* it's equivalent to:
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* tv.nsec -= NSEC_PER_SEC
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* tv.sec ++;
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*/
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if (res.tv.nsec >= NSEC_PER_SEC)
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res.tv64 += (u32)-NSEC_PER_SEC;
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return res;
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}
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/**
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* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
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* @kt: addend
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* @nsec: the scalar nsec value to add
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*
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* Return: The sum of @kt and @nsec in ktime_t format.
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*/
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extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
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/**
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* ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
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* @kt: minuend
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* @nsec: the scalar nsec value to subtract
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*
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* Return: The subtraction of @nsec from @kt in ktime_t format.
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*/
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extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);
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/**
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* timespec_to_ktime - convert a timespec to ktime_t format
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* @ts: the timespec variable to convert
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*
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* Return: A ktime_t variable with the converted timespec value.
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*/
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static inline ktime_t timespec_to_ktime(const struct timespec ts)
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{
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return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
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.nsec = (s32)ts.tv_nsec } };
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}
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/**
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* timeval_to_ktime - convert a timeval to ktime_t format
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* @tv: the timeval variable to convert
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*
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* Return: A ktime_t variable with the converted timeval value.
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*/
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static inline ktime_t timeval_to_ktime(const struct timeval tv)
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{
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return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
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.nsec = (s32)(tv.tv_usec *
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NSEC_PER_USEC) } };
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}
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/**
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* ktime_to_timespec - convert a ktime_t variable to timespec format
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* @kt: the ktime_t variable to convert
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*
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* Return: The timespec representation of the ktime value.
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*/
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static inline struct timespec ktime_to_timespec(const ktime_t kt)
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{
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return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
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.tv_nsec = (long) kt.tv.nsec };
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}
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/**
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* ktime_to_timeval - convert a ktime_t variable to timeval format
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* @kt: the ktime_t variable to convert
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*
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* Return: The timeval representation of the ktime value.
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*/
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static inline struct timeval ktime_to_timeval(const ktime_t kt)
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{
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return (struct timeval) {
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.tv_sec = (time_t) kt.tv.sec,
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.tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
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}
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/**
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* ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
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* @kt: the ktime_t variable to convert
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*
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* Return: The scalar nanoseconds representation of @kt.
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*/
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static inline s64 ktime_to_ns(const ktime_t kt)
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{
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return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
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}
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#endif /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
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/**
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* ktime_equal - Compares two ktime_t variables to see if they are equal
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Compare two ktime_t variables.
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*
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* Return: 1 if equal.
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*/
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static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
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{
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return cmp1.tv64 == cmp2.tv64;
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}
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/**
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* ktime_compare - Compares two ktime_t variables for less, greater or equal
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* @cmp1: comparable1
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* @cmp2: comparable2
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*
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* Return: ...
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* cmp1 < cmp2: return <0
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* cmp1 == cmp2: return 0
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* cmp1 > cmp2: return >0
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*/
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static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
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{
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if (cmp1.tv64 < cmp2.tv64)
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return -1;
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if (cmp1.tv64 > cmp2.tv64)
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return 1;
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return 0;
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}
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static inline s64 ktime_to_us(const ktime_t kt)
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{
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struct timeval tv = ktime_to_timeval(kt);
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return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
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}
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static inline s64 ktime_to_ms(const ktime_t kt)
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{
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struct timeval tv = ktime_to_timeval(kt);
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return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC;
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}
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static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
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{
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return ktime_to_us(ktime_sub(later, earlier));
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}
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static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
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{
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return ktime_add_ns(kt, usec * NSEC_PER_USEC);
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}
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static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
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{
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return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
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}
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static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
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{
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return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
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}
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extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
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/**
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* ktime_to_timespec_cond - convert a ktime_t variable to timespec
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* format only if the variable contains data
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* @kt: the ktime_t variable to convert
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* @ts: the timespec variable to store the result in
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*
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* Return: %true if there was a successful conversion, %false if kt was 0.
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*/
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static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
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struct timespec *ts)
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{
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if (kt.tv64) {
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*ts = ktime_to_timespec(kt);
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return true;
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} else {
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return false;
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}
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}
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/*
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* The resolution of the clocks. The resolution value is returned in
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* the clock_getres() system call to give application programmers an
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* idea of the (in)accuracy of timers. Timer values are rounded up to
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* this resolution values.
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*/
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#define LOW_RES_NSEC TICK_NSEC
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#define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC }
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/* Get the monotonic time in timespec format: */
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extern void ktime_get_ts(struct timespec *ts);
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/* Get the real (wall-) time in timespec format: */
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#define ktime_get_real_ts(ts) getnstimeofday(ts)
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static inline ktime_t ns_to_ktime(u64 ns)
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{
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static const ktime_t ktime_zero = { .tv64 = 0 };
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return ktime_add_ns(ktime_zero, ns);
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}
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static inline ktime_t ms_to_ktime(u64 ms)
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{
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static const ktime_t ktime_zero = { .tv64 = 0 };
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return ktime_add_ms(ktime_zero, ms);
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}
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#endif
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