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authorLinus Torvalds <torvalds@linux-foundation.org>2023-08-30 20:05:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-08-30 20:05:42 -0700
commitcd99b9eb4b702563c5ac7d26b632a628f5a832a5 (patch)
treeff96773806b6bb1efece11d8b7678ae43d71411e /kernel/time
parentf8fd5c24830fbc259ba7d5e72817c9867c01b8e8 (diff)
parentc63594f2d66690805eb78b75e4b8e8dc9f2672bf (diff)
Merge tag 'docs-6.6' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet: "Documentation work keeps chugging along; this includes: - Work from Carlos Bilbao to integrate rustdoc output into the generated HTML documentation. This took some work to figure out how to do it without slowing the docs build and without creating people who don't have Rust installed, but Carlos got there - Move the loongarch and mips architecture documentation under Documentation/arch/ - Some more maintainer documentation from Jakub ... plus the usual assortment of updates, translations, and fixes" * tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits) Docu: genericirq.rst: fix irq-example input: docs: pxrc: remove reference to phoenix-sim Documentation: serial-console: Fix literal block marker docs/mm: remove references to hmm_mirror ops and clean typos docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add() Documentation: Fix typos Documentation/ABI: Fix typos scripts: kernel-doc: fix macro handling in enums scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN] Documentation: riscv: Update boot image header since EFI stub is supported Documentation: riscv: Add early boot document Documentation: arm: Add bootargs to the table of added DT parameters docs: kernel-parameters: Refer to the correct bitmap function doc: update params of memhp_default_state= docs: Add book to process/kernel-docs.rst docs: sparse: fix invalid link addresses docs: vfs: clean up after the iterate() removal docs: Add a section on surveys to the researcher guidelines docs: move mips under arch docs: move loongarch under arch ...
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/time.c169
1 files changed, 158 insertions, 11 deletions
diff --git a/kernel/time/time.c b/kernel/time/time.c
index f4198af60fee..642647f5046b 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -365,11 +365,14 @@ SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp)
}
#endif
-/*
- * Convert jiffies to milliseconds and back.
+/**
+ * jiffies_to_msecs - Convert jiffies to milliseconds
+ * @j: jiffies value
*
* Avoid unnecessary multiplications/divisions in the
- * two most common HZ cases:
+ * two most common HZ cases.
+ *
+ * Return: milliseconds value
*/
unsigned int jiffies_to_msecs(const unsigned long j)
{
@@ -388,6 +391,12 @@ unsigned int jiffies_to_msecs(const unsigned long j)
}
EXPORT_SYMBOL(jiffies_to_msecs);
+/**
+ * jiffies_to_usecs - Convert jiffies to microseconds
+ * @j: jiffies value
+ *
+ * Return: microseconds value
+ */
unsigned int jiffies_to_usecs(const unsigned long j)
{
/*
@@ -408,8 +417,15 @@ unsigned int jiffies_to_usecs(const unsigned long j)
}
EXPORT_SYMBOL(jiffies_to_usecs);
-/*
+/**
* mktime64 - Converts date to seconds.
+ * @year0: year to convert
+ * @mon0: month to convert
+ * @day: day to convert
+ * @hour: hour to convert
+ * @min: minute to convert
+ * @sec: second to convert
+ *
* 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.
@@ -427,6 +443,8 @@ EXPORT_SYMBOL(jiffies_to_usecs);
*
* An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
* tomorrow - (allowable under ISO 8601) is supported.
+ *
+ * Return: seconds since the epoch time for the given input date
*/
time64_t mktime64(const unsigned int year0, const unsigned int mon0,
const unsigned int day, const unsigned int hour,
@@ -471,8 +489,7 @@ EXPORT_SYMBOL(ns_to_kernel_old_timeval);
* 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
+ * 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_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
@@ -501,7 +518,7 @@ EXPORT_SYMBOL(set_normalized_timespec64);
* ns_to_timespec64 - Convert nanoseconds to timespec64
* @nsec: the nanoseconds value to be converted
*
- * Returns the timespec64 representation of the nsec parameter.
+ * Return: the timespec64 representation of the nsec parameter.
*/
struct timespec64 ns_to_timespec64(s64 nsec)
{
@@ -548,6 +565,8 @@ EXPORT_SYMBOL(ns_to_timespec64);
* runtime.
* The _msecs_to_jiffies helpers are the HZ dependent conversion
* routines found in include/linux/jiffies.h
+ *
+ * Return: jiffies value
*/
unsigned long __msecs_to_jiffies(const unsigned int m)
{
@@ -560,6 +579,12 @@ unsigned long __msecs_to_jiffies(const unsigned int m)
}
EXPORT_SYMBOL(__msecs_to_jiffies);
+/**
+ * __usecs_to_jiffies: - convert microseconds to jiffies
+ * @u: time in milliseconds
+ *
+ * Return: jiffies value
+ */
unsigned long __usecs_to_jiffies(const unsigned int u)
{
if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
@@ -568,7 +593,10 @@ unsigned long __usecs_to_jiffies(const unsigned int u)
}
EXPORT_SYMBOL(__usecs_to_jiffies);
-/*
+/**
+ * timespec64_to_jiffies - convert a timespec64 value to jiffies
+ * @value: pointer to &struct timespec64
+ *
* 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 boundaries. I.e. the line:
@@ -582,8 +610,9 @@ EXPORT_SYMBOL(__usecs_to_jiffies);
*
* The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
* value to a scaled second value.
+ *
+ * Return: jiffies value
*/
-
unsigned long
timespec64_to_jiffies(const struct timespec64 *value)
{
@@ -601,6 +630,11 @@ timespec64_to_jiffies(const struct timespec64 *value)
}
EXPORT_SYMBOL(timespec64_to_jiffies);
+/**
+ * jiffies_to_timespec64 - convert jiffies value to &struct timespec64
+ * @jiffies: jiffies value
+ * @value: pointer to &struct timespec64
+ */
void
jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
{
@@ -618,6 +652,13 @@ EXPORT_SYMBOL(jiffies_to_timespec64);
/*
* Convert jiffies/jiffies_64 to clock_t and back.
*/
+
+/**
+ * jiffies_to_clock_t - Convert jiffies to clock_t
+ * @x: jiffies value
+ *
+ * Return: jiffies converted to clock_t (CLOCKS_PER_SEC)
+ */
clock_t jiffies_to_clock_t(unsigned long x)
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
@@ -632,6 +673,12 @@ clock_t jiffies_to_clock_t(unsigned long x)
}
EXPORT_SYMBOL(jiffies_to_clock_t);
+/**
+ * clock_t_to_jiffies - Convert clock_t to jiffies
+ * @x: clock_t value
+ *
+ * Return: clock_t value converted to jiffies
+ */
unsigned long clock_t_to_jiffies(unsigned long x)
{
#if (HZ % USER_HZ)==0
@@ -649,6 +696,12 @@ unsigned long clock_t_to_jiffies(unsigned long x)
}
EXPORT_SYMBOL(clock_t_to_jiffies);
+/**
+ * jiffies_64_to_clock_t - Convert jiffies_64 to clock_t
+ * @x: jiffies_64 value
+ *
+ * Return: jiffies_64 value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
+ */
u64 jiffies_64_to_clock_t(u64 x)
{
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
@@ -671,6 +724,12 @@ u64 jiffies_64_to_clock_t(u64 x)
}
EXPORT_SYMBOL(jiffies_64_to_clock_t);
+/**
+ * nsec_to_clock_t - Convert nsec value to clock_t
+ * @x: nsec value
+ *
+ * Return: nsec value converted to 64-bit "clock_t" (CLOCKS_PER_SEC)
+ */
u64 nsec_to_clock_t(u64 x)
{
#if (NSEC_PER_SEC % USER_HZ) == 0
@@ -687,6 +746,12 @@ u64 nsec_to_clock_t(u64 x)
#endif
}
+/**
+ * jiffies64_to_nsecs - Convert jiffies64 to nanoseconds
+ * @j: jiffies64 value
+ *
+ * Return: nanoseconds value
+ */
u64 jiffies64_to_nsecs(u64 j)
{
#if !(NSEC_PER_SEC % HZ)
@@ -697,6 +762,12 @@ u64 jiffies64_to_nsecs(u64 j)
}
EXPORT_SYMBOL(jiffies64_to_nsecs);
+/**
+ * jiffies64_to_msecs - Convert jiffies64 to milliseconds
+ * @j: jiffies64 value
+ *
+ * Return: milliseconds value
+ */
u64 jiffies64_to_msecs(const u64 j)
{
#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
@@ -719,6 +790,8 @@ EXPORT_SYMBOL(jiffies64_to_msecs);
* note:
* NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
* ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ *
+ * Return: nsecs converted to jiffies64 value
*/
u64 nsecs_to_jiffies64(u64 n)
{
@@ -750,6 +823,8 @@ EXPORT_SYMBOL(nsecs_to_jiffies64);
* note:
* NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
* ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ *
+ * Return: nsecs converted to jiffies value
*/
unsigned long nsecs_to_jiffies(u64 n)
{
@@ -757,10 +832,16 @@ unsigned long nsecs_to_jiffies(u64 n)
}
EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
-/*
- * Add two timespec64 values and do a safety check for overflow.
+/**
+ * timespec64_add_safe - Add two timespec64 values and do a safety check
+ * for overflow.
+ * @lhs: first (left) timespec64 to add
+ * @rhs: second (right) timespec64 to add
+ *
* It's assumed that both values are valid (>= 0).
* And, each timespec64 is in normalized form.
+ *
+ * Return: sum of @lhs + @rhs
*/
struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
const struct timespec64 rhs)
@@ -778,6 +859,15 @@ struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
return res;
}
+/**
+ * get_timespec64 - get user's time value into kernel space
+ * @ts: destination &struct timespec64
+ * @uts: user's time value as &struct __kernel_timespec
+ *
+ * Handles compat or 32-bit modes.
+ *
+ * Return: %0 on success or negative errno on error
+ */
int get_timespec64(struct timespec64 *ts,
const struct __kernel_timespec __user *uts)
{
@@ -801,6 +891,14 @@ int get_timespec64(struct timespec64 *ts,
}
EXPORT_SYMBOL_GPL(get_timespec64);
+/**
+ * put_timespec64 - convert timespec64 value to __kernel_timespec format and
+ * copy the latter to userspace
+ * @ts: input &struct timespec64
+ * @uts: user's &struct __kernel_timespec
+ *
+ * Return: %0 on success or negative errno on error
+ */
int put_timespec64(const struct timespec64 *ts,
struct __kernel_timespec __user *uts)
{
@@ -839,6 +937,15 @@ static int __put_old_timespec32(const struct timespec64 *ts64,
return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
}
+/**
+ * get_old_timespec32 - get user's old-format time value into kernel space
+ * @ts: destination &struct timespec64
+ * @uts: user's old-format time value (&struct old_timespec32)
+ *
+ * Handles X86_X32_ABI compatibility conversion.
+ *
+ * Return: %0 on success or negative errno on error
+ */
int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
{
if (COMPAT_USE_64BIT_TIME)
@@ -848,6 +955,16 @@ int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
}
EXPORT_SYMBOL_GPL(get_old_timespec32);
+/**
+ * put_old_timespec32 - convert timespec64 value to &struct old_timespec32 and
+ * copy the latter to userspace
+ * @ts: input &struct timespec64
+ * @uts: user's &struct old_timespec32
+ *
+ * Handles X86_X32_ABI compatibility conversion.
+ *
+ * Return: %0 on success or negative errno on error
+ */
int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
{
if (COMPAT_USE_64BIT_TIME)
@@ -857,6 +974,13 @@ int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
}
EXPORT_SYMBOL_GPL(put_old_timespec32);
+/**
+ * get_itimerspec64 - get user's &struct __kernel_itimerspec into kernel space
+ * @it: destination &struct itimerspec64
+ * @uit: user's &struct __kernel_itimerspec
+ *
+ * Return: %0 on success or negative errno on error
+ */
int get_itimerspec64(struct itimerspec64 *it,
const struct __kernel_itimerspec __user *uit)
{
@@ -872,6 +996,14 @@ int get_itimerspec64(struct itimerspec64 *it,
}
EXPORT_SYMBOL_GPL(get_itimerspec64);
+/**
+ * put_itimerspec64 - convert &struct itimerspec64 to __kernel_itimerspec format
+ * and copy the latter to userspace
+ * @it: input &struct itimerspec64
+ * @uit: user's &struct __kernel_itimerspec
+ *
+ * Return: %0 on success or negative errno on error
+ */
int put_itimerspec64(const struct itimerspec64 *it,
struct __kernel_itimerspec __user *uit)
{
@@ -887,6 +1019,13 @@ int put_itimerspec64(const struct itimerspec64 *it,
}
EXPORT_SYMBOL_GPL(put_itimerspec64);
+/**
+ * get_old_itimerspec32 - get user's &struct old_itimerspec32 into kernel space
+ * @its: destination &struct itimerspec64
+ * @uits: user's &struct old_itimerspec32
+ *
+ * Return: %0 on success or negative errno on error
+ */
int get_old_itimerspec32(struct itimerspec64 *its,
const struct old_itimerspec32 __user *uits)
{
@@ -898,6 +1037,14 @@ int get_old_itimerspec32(struct itimerspec64 *its,
}
EXPORT_SYMBOL_GPL(get_old_itimerspec32);
+/**
+ * put_old_itimerspec32 - convert &struct itimerspec64 to &struct
+ * old_itimerspec32 and copy the latter to userspace
+ * @its: input &struct itimerspec64
+ * @uits: user's &struct old_itimerspec32
+ *
+ * Return: %0 on success or negative errno on error
+ */
int put_old_itimerspec32(const struct itimerspec64 *its,
struct old_itimerspec32 __user *uits)
{