[PATCH 1/3] docs: time: make separate section for time and timers

[PATCH 1/3] docs: time: make separate section for time and timers

[Randy Dunlap]

Give time & timer APIs their own section and begin adding
entries to that section. Move hrtimers immediately after
this new section so that they are all together.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---
 Documentation/driver-api/basics.rst |   27 +++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff -- a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
--- a/Documentation/driver-api/basics.rst
+++ b/Documentation/driver-api/basics.rst
@@ -15,8 +15,8 @@ Driver device table
    :no-identifiers: pci_device_id
 
 
-Delaying, scheduling, and timer routines
-----------------------------------------
+Delaying and scheduling routines
+--------------------------------
 
 .. kernel-doc:: include/linux/sched.h
    :internal:
@@ -33,16 +33,16 @@ Delaying, scheduling, and timer routines
 .. kernel-doc:: include/linux/completion.h
    :internal:
 
-.. kernel-doc:: kernel/time/timer.c
-   :export:
-
-Wait queues and Wake events
----------------------------
+Time and timer routines
+-----------------------
 
-.. kernel-doc:: include/linux/wait.h
+.. kernel-doc:: include/linux/jiffies.h
    :internal:
 
-.. kernel-doc:: kernel/sched/wait.c
+.. kernel-doc:: kernel/time/time.c
+   :export:
+
+.. kernel-doc:: kernel/time/timer.c
    :export:
 
 High-resolution timers
@@ -57,6 +57,15 @@ High-resolution timers
 .. kernel-doc:: kernel/time/hrtimer.c
    :export:
 
+Wait queues and Wake events
+---------------------------
+
+.. kernel-doc:: include/linux/wait.h
+   :internal:
+
+.. kernel-doc:: kernel/sched/wait.c
+   :export:
+
 Internal Functions
 ------------------
 

[PATCH 2/3] jiffies: add kernel-doc for all APIs

[Randy Dunlap]

Add kernel-doc notation in <linux/jiffies.h> for interfaces that
don't already have it (i.e. most interfaces).

Fix some formatting and typos in other comments.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---
 include/linux/jiffies.h |  197 +++++++++++++++++++++++++++++++++-----
 1 file changed, 176 insertions(+), 21 deletions(-)

diff -- a/include/linux/jiffies.h b/include/linux/jiffies.h
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -72,9 +72,15 @@ extern int register_refined_jiffies(long
 #endif
 
 /*
- * The 64-bit value is not atomic - you MUST NOT read it
+ * The 64-bit value is not atomic on 32-bit systems - you MUST NOT read it
  * without sampling the sequence number in jiffies_lock.
  * get_jiffies_64() will do this for you as appropriate.
+ *
+ * jiffies and jiffies_64 are at the same address for little-endian systems
+ * and for 64-bit big-endian systems.
+ * On 32-bit big-endian systems, jiffies is the lower 32 bits of jiffies_64
+ * (i.e., at address @jiffies_64 + 4).
+ * See arch/ARCH/kernel/vmlinux.lds.S
  */
 extern u64 __cacheline_aligned_in_smp jiffies_64;
 extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies;
@@ -82,6 +88,14 @@ extern unsigned long volatile __cachelin
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void);
 #else
+/**
+ * get_jiffies_64 - read the 64-bit non-atomic jiffies_64 value
+ *
+ * When BITS_PER_LONG < 64, this uses sequence number sampling using
+ * jiffies_lock to protect the 64-bit read.
+ *
+ * Return: current 64-bit jiffies value
+ */
 static inline u64 get_jiffies_64(void)
 {
 	return (u64)jiffies;
@@ -89,39 +103,76 @@ static inline u64 get_jiffies_64(void)
 #endif
 
 /*
- *	These inlines deal with timer wrapping correctly. You are 
- *	strongly encouraged to use them
+ *	These inlines deal with timer wrapping correctly. You are
+ *	strongly encouraged to use them:
  *	1. Because people otherwise forget
  *	2. Because if the timer wrap changes in future you won't have to
  *	   alter your driver code.
- *
- * time_after(a,b) returns true if the time a is after time b.
+ */
+
+/**
+ * time_after - returns true if the time a is after time b.
+ * @a: first comparable as unsigned long
+ * @b: second comparable as unsigned long
  *
  * Do this with "<0" and ">=0" to only test the sign of the result. A
  * good compiler would generate better code (and a really good compiler
  * wouldn't care). Gcc is currently neither.
+ *
+ * Return: %true is time a is after time b, otherwise %false.
  */
 #define time_after(a,b)		\
 	(typecheck(unsigned long, a) && \
 	 typecheck(unsigned long, b) && \
 	 ((long)((b) - (a)) < 0))
+/**
+ * time_before - returns true if the time a is before time b.
+ * @a: first comparable as unsigned long
+ * @b: second comparable as unsigned long
+ *
+ * Return: %true is time a is before time b, otherwise %false.
+ */
 #define time_before(a,b)	time_after(b,a)
 
+/**
+ * time_after_eq - returns true if the time a is after or the same as time b.
+ * @a: first comparable as unsigned long
+ * @b: second comparable as unsigned long
+ *
+ * Return: %true is time a is after or the same as time b, otherwise %false.
+ */
 #define time_after_eq(a,b)	\
 	(typecheck(unsigned long, a) && \
 	 typecheck(unsigned long, b) && \
 	 ((long)((a) - (b)) >= 0))
+/**
+ * time_before_eq - returns true if the time a is before or the same as time b.
+ * @a: first comparable as unsigned long
+ * @b: second comparable as unsigned long
+ *
+ * Return: %true is time a is before or the same as time b, otherwise %false.
+ */
 #define time_before_eq(a,b)	time_after_eq(b,a)
 
-/*
- * Calculate whether a is in the range of [b, c].
+/**
+ * time_in_range - Calculate whether a is in the range of [b, c].
+ * @a: time to test
+ * @b: beginning of the range
+ * @c: end of the range
+ *
+ * Return: %true is time a is in the range [b, c], otherwise %false.
  */
 #define time_in_range(a,b,c) \
 	(time_after_eq(a,b) && \
 	 time_before_eq(a,c))
 
-/*
- * Calculate whether a is in the range of [b, c).
+/**
+ * time_in_range_open - Calculate whether a is in the range of [b, c).
+ * @a: time to test
+ * @b: beginning of the range
+ * @c: end of the range
+ *
+ * Return: %true is time a is in the range [b, c), otherwise %false.
  */
 #define time_in_range_open(a,b,c) \
 	(time_after_eq(a,b) && \
@@ -129,45 +180,138 @@ static inline u64 get_jiffies_64(void)
 
 /* Same as above, but does so with platform independent 64bit types.
  * These must be used when utilizing jiffies_64 (i.e. return value of
- * get_jiffies_64() */
+ * get_jiffies_64()). */
+
+/**
+ * time_after64 - returns true if the time a is after time b.
+ * @a: first comparable as __u64
+ * @b: second comparable as __u64
+ *
+ * This must be used when utilizing jiffies_64 (i.e. return value of
+ * get_jiffies_64()).
+ *
+ * Return: %true is time a is after time b, otherwise %false.
+ */
 #define time_after64(a,b)	\
 	(typecheck(__u64, a) &&	\
 	 typecheck(__u64, b) && \
 	 ((__s64)((b) - (a)) < 0))
+/**
+ * time_before64 - returns true if the time a is before time b.
+ * @a: first comparable as __u64
+ * @b: second comparable as __u64
+ *
+ * This must be used when utilizing jiffies_64 (i.e. return value of
+ * get_jiffies_64()).
+ *
+ * Return: %true is time a is before time b, otherwise %false.
+ */
 #define time_before64(a,b)	time_after64(b,a)
 
+/**
+ * time_after_eq64 - returns true if the time a is after or the same as time b.
+ * @a: first comparable as __u64
+ * @b: second comparable as __u64
+ *
+ * This must be used when utilizing jiffies_64 (i.e. return value of
+ * get_jiffies_64()).
+ *
+ * Return: %true is time a is after or the same as time b, otherwise %false.
+ */
 #define time_after_eq64(a,b)	\
 	(typecheck(__u64, a) && \
 	 typecheck(__u64, b) && \
 	 ((__s64)((a) - (b)) >= 0))
+/**
+ * time_before_eq64 - returns true if the time a is before or the same as time b.
+ * @a: first comparable as __u64
+ * @b: second comparable as __u64
+ *
+ * This must be used when utilizing jiffies_64 (i.e. return value of
+ * get_jiffies_64()).
+ *
+ * Return: %true is time a is before or the same as time b, otherwise %false.
+ */
 #define time_before_eq64(a,b)	time_after_eq64(b,a)
 
+/**
+ * time_in_range64 - Calculate whether a is in the range of [b, c].
+ * @a: time to test
+ * @b: beginning of the range
+ * @c: end of the range
+ *
+ * Return: %true is time a is in the range [b, c], otherwise %false.
+ */
 #define time_in_range64(a, b, c) \
 	(time_after_eq64(a, b) && \
 	 time_before_eq64(a, c))
 
 /*
- * These four macros compare jiffies and 'a' for convenience.
+ * These eight macros compare jiffies[_64] and 'a' for convenience.
  */
 
-/* time_is_before_jiffies(a) return true if a is before jiffies */
+/**
+ * time_is_before_jiffies - return true if a is before jiffies
+ * @a: time (unsigned long) to compare to jiffies
+ *
+ * Return: %true is time a is before jiffies, otherwise %false.
+ */
 #define time_is_before_jiffies(a) time_after(jiffies, a)
+/**
+ * time_is_before_jiffies64 - return true if a is before jiffies_64
+ * @a: time (__u64) to compare to jiffies_64
+ *
+ * Return: %true is time a is before jiffies_64, otherwise %false.
+ */
 #define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a)
 
-/* time_is_after_jiffies(a) return true if a is after jiffies */
+/**
+ * time_is_after_jiffies - return true if a is after jiffies
+ * @a: time (unsigned long) to compare to jiffies
+ *
+ * Return: %true is time a is after jiffies, otherwise %false.
+ */
 #define time_is_after_jiffies(a) time_before(jiffies, a)
+/**
+ * time_is_after_jiffies64 - return true if a is after jiffies_64
+ * @a: time (__u64) to compare to jiffies_64
+ *
+ * Return: %true is time a is after jiffies_64, otherwise %false.
+ */
 #define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a)
 
-/* time_is_before_eq_jiffies(a) return true if a is before or equal to jiffies*/
+/**
+ * time_is_before_eq_jiffies - return true if a is before or equal to jiffies
+ * @a: time (unsigned long) to compare to jiffies
+ *
+ * Return: %true is time a is before or the same as jiffies, otherwise %false.
+ */
 #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a)
+/**
+ * time_is_before_eq_jiffies64 - return true if a is before or equal to jiffies_64
+ * @a: time (__u64) to compare to jiffies_64
+ *
+ * Return: %true is time a is before or the same jiffies_64, otherwise %false.
+ */
 #define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a)
 
-/* time_is_after_eq_jiffies(a) return true if a is after or equal to jiffies*/
+/**
+ * time_is_after_eq_jiffies - return true if a is after or equal to jiffies
+ * @a: time (unsigned long) to compare to jiffies
+ *
+ * Return: %true is time a is after or the same as jiffies, otherwise %false.
+ */
 #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a)
+/**
+ * time_is_after_eq_jiffies64 - return true if a is after or equal to jiffies_64
+ * @a: time (__u64) to compare to jiffies_64
+ *
+ * Return: %true is time a is after or the same as jiffies_64, otherwise %false.
+ */
 #define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a)
 
 /*
- * Have the 32 bit jiffies value wrap 5 minutes after boot
+ * Have the 32-bit jiffies value wrap 5 minutes after boot
  * so jiffies wrap bugs show up earlier.
  */
 #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
@@ -278,7 +422,7 @@ extern unsigned long preset_lpj;
 #if BITS_PER_LONG < 64
 # define MAX_SEC_IN_JIFFIES \
 	(long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC)
-#else	/* take care of overflow on 64 bits machines */
+#else	/* take care of overflow on 64-bit machines */
 # define MAX_SEC_IN_JIFFIES \
 	(SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1)
 
@@ -290,6 +434,12 @@ extern unsigned long preset_lpj;
 extern unsigned int jiffies_to_msecs(const unsigned long j);
 extern unsigned int jiffies_to_usecs(const unsigned long j);
 
+/**
+ * jiffies_to_nsecs - Convert jiffies to nanoseconds
+ * @j: jiffies value
+ *
+ * Return: nanoseconds value
+ */
 static inline u64 jiffies_to_nsecs(const unsigned long j)
 {
 	return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC;
@@ -353,12 +503,14 @@ static inline unsigned long _msecs_to_ji
  *
  * msecs_to_jiffies() checks for the passed in value being a constant
  * via __builtin_constant_p() allowing gcc to eliminate most of the
- * code, __msecs_to_jiffies() is called if the value passed does not
+ * code. __msecs_to_jiffies() is called if the value passed does not
  * allow constant folding and the actual conversion must be done at
  * runtime.
- * the HZ range specific helpers _msecs_to_jiffies() are called both
+ * The HZ range specific helpers _msecs_to_jiffies() are called both
  * directly here and from __msecs_to_jiffies() in the case where
  * constant folding is not possible.
+ *
+ * Return: jiffies value
  */
 static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
 {
@@ -400,12 +552,14 @@ static inline unsigned long _usecs_to_ji
  *
  * usecs_to_jiffies() checks for the passed in value being a constant
  * via __builtin_constant_p() allowing gcc to eliminate most of the
- * code, __usecs_to_jiffies() is called if the value passed does not
+ * code. __usecs_to_jiffies() is called if the value passed does not
  * allow constant folding and the actual conversion must be done at
  * runtime.
- * the HZ range specific helpers _usecs_to_jiffies() are called both
+ * The HZ range specific helpers _usecs_to_jiffies() are called both
  * directly here and from __msecs_to_jiffies() in the case where
  * constant folding is not possible.
+ *
+ * Return: jiffies value
  */
 static __always_inline unsigned long usecs_to_jiffies(const unsigned int u)
 {
@@ -422,6 +576,7 @@ extern unsigned long timespec64_to_jiffi
 extern void jiffies_to_timespec64(const unsigned long jiffies,
 				  struct timespec64 *value);
 extern clock_t jiffies_to_clock_t(unsigned long x);
+
 static inline clock_t jiffies_delta_to_clock_t(long delta)
 {
 	return jiffies_to_clock_t(max(0L, delta));

[PATCH 3/3] time: add kernel-doc in time.c

[Randy Dunlap]

Add kernel-doc for all APIs that do not already have it.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---
 kernel/time/time.c |  169 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 158 insertions(+), 11 deletions(-)

diff -- a/kernel/time/time.c b/kernel/time/time.c
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -365,11 +365,14 @@ SYSCALL_DEFINE1(adjtimex_time32, struct
 }
 #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 unsi
 }
 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 unsi
 }
 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 u
 }
 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 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 times
 }
 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
 }
 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(unsigne
 }
 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(co
 	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 st
 	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
 }
 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 time
 }
 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
 }
 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 itimer
 }
 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 itimersp
 }
 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)
 {

Re: [PATCH 2/3] jiffies: add kernel-doc for all APIs

[John Stultz]

On Mon, Jul 3, 2023 at 10:24 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Add kernel-doc notation in <linux/jiffies.h> for interfaces that
> don't already have it (i.e. most interfaces).
>
> Fix some formatting and typos in other comments.
>

Looks ok to me. Thanks for sending this out!

Acked-by: John Stultz <jstultz@google.com>

thanks
-john

Re: [PATCH 3/3] time: add kernel-doc in time.c

[John Stultz]

On Mon, Jul 3, 2023 at 10:24 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Add kernel-doc for all APIs that do not already have it.
>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: John Stultz <jstultz@google.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: linux-doc@vger.kernel.org

Acked-by: John Stultz <jstultz@google.com>

Thanks again!
-john

Re: [PATCH 1/3] docs: time: make separate section for time and timers

[Jonathan Corbet]

Randy Dunlap <rdunlap@infradead.org> writes:

> Give time & timer APIs their own section and begin adding
> entries to that section. Move hrtimers immediately after
> this new section so that they are all together.
>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: John Stultz <jstultz@google.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: linux-doc@vger.kernel.org
> ---
>  Documentation/driver-api/basics.rst |   27 +++++++++++++++++---------
>  1 file changed, 18 insertions(+), 9 deletions(-)

Series applied, thanks.

jon