Message-ID: <20230801050817.26872-1-rdunlap@infradead.org>
Date:   Mon, 31 Jul 2023 22:08:17 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     linux-kernel@...r.kernel.org
Cc:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: [PATCH v2] cpumask: kernel-doc cleanups and additions

Clean up some punctutation and abbreviations.
Add kernel-doc notation for one function and function return value
for 39 functions.

cpumask.h:
Fix some punctuation (plural vs. possessive).
Fix some abbreviations (ie. -> i.e., id -> ID).

Fix 35 warnings like this:
include/linux/cpumask.h:161: warning: No description found for return value of 'cpumask_first'

cpumask.c:
Add Return: value for 4 functions.
Add kernel-doc for cpumask_any_distribute().

Signed-off-by: Randy Dunlap <rdunlap@...radead.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
v2: combine the header & C source file patches (Andy);
    add Rev-by: Andy

 include/linux/cpumask.h |  113 +++++++++++++++++++++++---------------
 lib/cpumask.c           |   17 ++++-
 2 files changed, 81 insertions(+), 49 deletions(-)

diff -- a/include/linux/cpumask.h b/include/linux/cpumask.h
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -4,7 +4,7 @@
 
 /*
  * Cpumasks provide a bitmap suitable for representing the
- * set of CPU's in a system, one bit position per CPU number.  In general,
+ * set of CPUs in a system, one bit position per CPU number.  In general,
  * only nr_cpu_ids (<= NR_CPUS) bits are valid.
  */
 #include <linux/kernel.h>
@@ -97,7 +97,7 @@ static inline void set_nr_cpu_ids(unsign
  *
  *  If !CONFIG_HOTPLUG_CPU, present == possible, and active == online.
  *
- *  The cpu_possible_mask is fixed at boot time, as the set of CPU id's
+ *  The cpu_possible_mask is fixed at boot time, as the set of CPU IDs
  *  that it is possible might ever be plugged in at anytime during the
  *  life of that system boot.  The cpu_present_mask is dynamic(*),
  *  representing which CPUs are currently plugged in.  And
@@ -112,7 +112,7 @@ static inline void set_nr_cpu_ids(unsign
  *      hotplug, it's a copy of cpu_possible_mask, hence fixed at boot.
  *
  * Subtleties:
- * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
+ * 1) UP ARCHes (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
  *    assumption that their single CPU is online.  The UP
  *    cpu_{online,possible,present}_masks are placebos.  Changing them
  *    will have no useful affect on the following num_*_cpus()
@@ -155,7 +155,7 @@ static __always_inline unsigned int cpum
  * cpumask_first - get the first cpu in a cpumask
  * @srcp: the cpumask pointer
  *
- * Returns >= nr_cpu_ids if no cpus set.
+ * Return: >= nr_cpu_ids if no cpus set.
  */
 static inline unsigned int cpumask_first(const struct cpumask *srcp)
 {
@@ -166,7 +166,7 @@ static inline unsigned int cpumask_first
  * cpumask_first_zero - get the first unset cpu in a cpumask
  * @srcp: the cpumask pointer
  *
- * Returns >= nr_cpu_ids if all cpus are set.
+ * Return: >= nr_cpu_ids if all cpus are set.
  */
 static inline unsigned int cpumask_first_zero(const struct cpumask *srcp)
 {
@@ -178,7 +178,7 @@ static inline unsigned int cpumask_first
  * @srcp1: the first input
  * @srcp2: the second input
  *
- * Returns >= nr_cpu_ids if no cpus set in both.  See also cpumask_next_and().
+ * Return: >= nr_cpu_ids if no cpus set in both.  See also cpumask_next_and().
  */
 static inline
 unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask *srcp2)
@@ -190,7 +190,7 @@ unsigned int cpumask_first_and(const str
  * cpumask_last - get the last CPU in a cpumask
  * @srcp:	- the cpumask pointer
  *
- * Returns	>= nr_cpumask_bits if no CPUs set.
+ * Return:	>= nr_cpumask_bits if no CPUs set.
  */
 static inline unsigned int cpumask_last(const struct cpumask *srcp)
 {
@@ -199,10 +199,10 @@ static inline unsigned int cpumask_last(
 
 /**
  * cpumask_next - get the next cpu in a cpumask
- * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @n: the cpu prior to the place to search (i.e. return will be > @n)
  * @srcp: the cpumask pointer
  *
- * Returns >= nr_cpu_ids if no further cpus set.
+ * Return: >= nr_cpu_ids if no further cpus set.
  */
 static inline
 unsigned int cpumask_next(int n, const struct cpumask *srcp)
@@ -215,10 +215,10 @@ unsigned int cpumask_next(int n, const s
 
 /**
  * cpumask_next_zero - get the next unset cpu in a cpumask
- * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @n: the cpu prior to the place to search (i.e. return will be > @n)
  * @srcp: the cpumask pointer
  *
- * Returns >= nr_cpu_ids if no further cpus unset.
+ * Return: >= nr_cpu_ids if no further cpus unset.
  */
 static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 {
@@ -254,11 +254,11 @@ unsigned int cpumask_any_distribute(cons
 
 /**
  * cpumask_next_and - get the next cpu in *src1p & *src2p
- * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @n: the cpu prior to the place to search (i.e. return will be > @n)
  * @src1p: the first cpumask pointer
  * @src2p: the second cpumask pointer
  *
- * Returns >= nr_cpu_ids if no further cpus set in both.
+ * Return: >= nr_cpu_ids if no further cpus set in both.
  */
 static inline
 unsigned int cpumask_next_and(int n, const struct cpumask *src1p,
@@ -373,7 +373,7 @@ unsigned int __pure cpumask_next_wrap(in
  * @cpu: the cpu to ignore.
  *
  * Often used to find any cpu but smp_processor_id() in a mask.
- * Returns >= nr_cpu_ids if no cpus set.
+ * Return: >= nr_cpu_ids if no cpus set.
  */
 static inline
 unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
@@ -388,11 +388,11 @@ unsigned int cpumask_any_but(const struc
 }
 
 /**
- * cpumask_nth - get the first cpu in a cpumask
+ * cpumask_nth - get the Nth cpu in a cpumask
  * @srcp: the cpumask pointer
- * @cpu: the N'th cpu to find, starting from 0
+ * @cpu: the Nth cpu to find, starting from 0
  *
- * Returns >= nr_cpu_ids if such cpu doesn't exist.
+ * Return: >= nr_cpu_ids if such cpu doesn't exist.
  */
 static inline unsigned int cpumask_nth(unsigned int cpu, const struct cpumask *srcp)
 {
@@ -400,12 +400,12 @@ static inline unsigned int cpumask_nth(u
 }
 
 /**
- * cpumask_nth_and - get the first cpu in 2 cpumasks
+ * cpumask_nth_and - get the Nth cpu in 2 cpumasks
  * @srcp1: the cpumask pointer
  * @srcp2: the cpumask pointer
- * @cpu: the N'th cpu to find, starting from 0
+ * @cpu: the Nth cpu to find, starting from 0
  *
- * Returns >= nr_cpu_ids if such cpu doesn't exist.
+ * Return: >= nr_cpu_ids if such cpu doesn't exist.
  */
 static inline
 unsigned int cpumask_nth_and(unsigned int cpu, const struct cpumask *srcp1,
@@ -416,12 +416,12 @@ unsigned int cpumask_nth_and(unsigned in
 }
 
 /**
- * cpumask_nth_andnot - get the first cpu set in 1st cpumask, and clear in 2nd.
+ * cpumask_nth_andnot - get the Nth cpu set in 1st cpumask, and clear in 2nd.
  * @srcp1: the cpumask pointer
  * @srcp2: the cpumask pointer
- * @cpu: the N'th cpu to find, starting from 0
+ * @cpu: the Nth cpu to find, starting from 0
  *
- * Returns >= nr_cpu_ids if such cpu doesn't exist.
+ * Return: >= nr_cpu_ids if such cpu doesn't exist.
  */
 static inline
 unsigned int cpumask_nth_andnot(unsigned int cpu, const struct cpumask *srcp1,
@@ -436,9 +436,9 @@ unsigned int cpumask_nth_andnot(unsigned
  * @srcp1: the cpumask pointer
  * @srcp2: the cpumask pointer
  * @srcp3: the cpumask pointer
- * @cpu: the N'th cpu to find, starting from 0
+ * @cpu: the Nth cpu to find, starting from 0
  *
- * Returns >= nr_cpu_ids if such cpu doesn't exist.
+ * Return: >= nr_cpu_ids if such cpu doesn't exist.
  */
 static __always_inline
 unsigned int cpumask_nth_and_andnot(unsigned int cpu, const struct cpumask *srcp1,
@@ -497,7 +497,7 @@ static __always_inline void __cpumask_cl
  * @cpu: cpu number (< nr_cpu_ids)
  * @cpumask: the cpumask pointer
  *
- * Returns true if @cpu is set in @cpumask, else returns false
+ * Return: true if @cpu is set in @cpumask, else returns false
  */
 static __always_inline bool cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
 {
@@ -509,9 +509,9 @@ static __always_inline bool cpumask_test
  * @cpu: cpu number (< nr_cpu_ids)
  * @cpumask: the cpumask pointer
  *
- * Returns true if @cpu is set in old bitmap of @cpumask, else returns false
- *
  * test_and_set_bit wrapper for cpumasks.
+ *
+ * Return: true if @cpu is set in old bitmap of @cpumask, else returns false
  */
 static __always_inline bool cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
 {
@@ -523,9 +523,9 @@ static __always_inline bool cpumask_test
  * @cpu: cpu number (< nr_cpu_ids)
  * @cpumask: the cpumask pointer
  *
- * Returns true if @cpu is set in old bitmap of @cpumask, else returns false
- *
  * test_and_clear_bit wrapper for cpumasks.
+ *
+ * Return: true if @cpu is set in old bitmap of @cpumask, else returns false
  */
 static __always_inline bool cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
 {
@@ -560,7 +560,7 @@ static inline void cpumask_clear(struct
  * @src1p: the first input
  * @src2p: the second input
  *
- * If *@...p is empty, returns false, else returns true
+ * Return: false if *@...p is empty, else returns true
  */
 static inline bool cpumask_and(struct cpumask *dstp,
 			       const struct cpumask *src1p,
@@ -603,7 +603,7 @@ static inline void cpumask_xor(struct cp
  * @src1p: the first input
  * @src2p: the second input
  *
- * If *@...p is empty, returns false, else returns true
+ * Return: false if *@...p is empty, else returns true
  */
 static inline bool cpumask_andnot(struct cpumask *dstp,
 				  const struct cpumask *src1p,
@@ -617,6 +617,8 @@ static inline bool cpumask_andnot(struct
  * cpumask_equal - *src1p == *src2p
  * @src1p: the first input
  * @src2p: the second input
+ *
+ * Return: true if the cpumasks are equal, false if not
  */
 static inline bool cpumask_equal(const struct cpumask *src1p,
 				const struct cpumask *src2p)
@@ -630,6 +632,9 @@ static inline bool cpumask_equal(const s
  * @src1p: the first input
  * @src2p: the second input
  * @src3p: the third input
+ *
+ * Return: true if first cpumask ORed with second cpumask == third cpumask,
+ *	   otherwise false
  */
 static inline bool cpumask_or_equal(const struct cpumask *src1p,
 				    const struct cpumask *src2p,
@@ -643,6 +648,9 @@ static inline bool cpumask_or_equal(cons
  * cpumask_intersects - (*src1p & *src2p) != 0
  * @src1p: the first input
  * @src2p: the second input
+ *
+ * Return: true if first cpumask ANDed with second cpumask is non-empty,
+ *	   otherwise false
  */
 static inline bool cpumask_intersects(const struct cpumask *src1p,
 				     const struct cpumask *src2p)
@@ -656,7 +664,7 @@ static inline bool cpumask_intersects(co
  * @src1p: the first input
  * @src2p: the second input
  *
- * Returns true if *@...1p is a subset of *@...2p, else returns false
+ * Return: true if *@...1p is a subset of *@...2p, else returns false
  */
 static inline bool cpumask_subset(const struct cpumask *src1p,
 				 const struct cpumask *src2p)
@@ -668,6 +676,8 @@ static inline bool cpumask_subset(const
 /**
  * cpumask_empty - *srcp == 0
  * @srcp: the cpumask to that all cpus < nr_cpu_ids are clear.
+ *
+ * Return: true if srcp is empty (has no bits set), else false
  */
 static inline bool cpumask_empty(const struct cpumask *srcp)
 {
@@ -677,6 +687,8 @@ static inline bool cpumask_empty(const s
 /**
  * cpumask_full - *srcp == 0xFFFFFFFF...
  * @srcp: the cpumask to that all cpus < nr_cpu_ids are set.
+ *
+ * Return: true if srcp is full (has all bits set), else false
  */
 static inline bool cpumask_full(const struct cpumask *srcp)
 {
@@ -686,6 +698,8 @@ static inline bool cpumask_full(const st
 /**
  * cpumask_weight - Count of bits in *srcp
  * @srcp: the cpumask to count bits (< nr_cpu_ids) in.
+ *
+ * Return: count of bits set in *srcp
  */
 static inline unsigned int cpumask_weight(const struct cpumask *srcp)
 {
@@ -696,6 +710,8 @@ static inline unsigned int cpumask_weigh
  * cpumask_weight_and - Count of bits in (*srcp1 & *srcp2)
  * @srcp1: the cpumask to count bits (< nr_cpu_ids) in.
  * @srcp2: the cpumask to count bits (< nr_cpu_ids) in.
+ *
+ * Return: count of bits set in both *srcp1 and *srcp2
  */
 static inline unsigned int cpumask_weight_and(const struct cpumask *srcp1,
 						const struct cpumask *srcp2)
@@ -744,7 +760,7 @@ static inline void cpumask_copy(struct c
  * cpumask_any - pick a "random" cpu from *srcp
  * @srcp: the input cpumask
  *
- * Returns >= nr_cpu_ids if no cpus set.
+ * Return: >= nr_cpu_ids if no cpus set.
  */
 #define cpumask_any(srcp) cpumask_first(srcp)
 
@@ -753,7 +769,7 @@ static inline void cpumask_copy(struct c
  * @mask1: the first input cpumask
  * @mask2: the second input cpumask
  *
- * Returns >= nr_cpu_ids if no cpus set.
+ * Return: >= nr_cpu_ids if no cpus set.
  */
 #define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2))
 
@@ -769,7 +785,7 @@ static inline void cpumask_copy(struct c
  * @len: the length of the buffer
  * @dstp: the cpumask to set.
  *
- * Returns -errno, or 0 for success.
+ * Return: -errno, or 0 for success.
  */
 static inline int cpumask_parse_user(const char __user *buf, int len,
 				     struct cpumask *dstp)
@@ -783,7 +799,7 @@ static inline int cpumask_parse_user(con
  * @len: the length of the buffer
  * @dstp: the cpumask to set.
  *
- * Returns -errno, or 0 for success.
+ * Return: -errno, or 0 for success.
  */
 static inline int cpumask_parselist_user(const char __user *buf, int len,
 				     struct cpumask *dstp)
@@ -797,7 +813,7 @@ static inline int cpumask_parselist_user
  * @buf: the buffer to extract from
  * @dstp: the cpumask to set.
  *
- * Returns -errno, or 0 for success.
+ * Return: -errno, or 0 for success.
  */
 static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
 {
@@ -809,7 +825,7 @@ static inline int cpumask_parse(const ch
  * @buf: the buffer to extract from
  * @dstp: the cpumask to set.
  *
- * Returns -errno, or 0 for success.
+ * Return: -errno, or 0 for success.
  */
 static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
 {
@@ -817,7 +833,9 @@ static inline int cpulist_parse(const ch
 }
 
 /**
- * cpumask_size - size to allocate for a 'struct cpumask' in bytes
+ * cpumask_size - calculate size to allocate for a 'struct cpumask' in bytes
+ *
+ * Return: size to allocate for a &struct cpumask in bytes
  */
 static inline unsigned int cpumask_size(void)
 {
@@ -831,7 +849,7 @@ static inline unsigned int cpumask_size(
  * little more difficult, we typedef cpumask_var_t to an array or a
  * pointer: doing &mask on an array is a noop, so it still works.
  *
- * ie.
+ * i.e.
  *	cpumask_var_t tmpmask;
  *	if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
  *		return -ENOMEM;
@@ -887,6 +905,8 @@ bool zalloc_cpumask_var_node(cpumask_var
  * a nop returning a constant 1 (in <linux/cpumask.h>).
  *
  * See alloc_cpumask_var_node.
+ *
+ * Return: %true if allocation succeeded, %false if not
  */
 static inline
 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
@@ -1025,7 +1045,7 @@ set_cpu_dying(unsigned int cpu, bool dyi
 }
 
 /**
- * to_cpumask - convert an NR_CPUS bitmap to a struct cpumask *
+ * to_cpumask - convert a NR_CPUS bitmap to a struct cpumask *
  * @bitmap: the bitmap
  *
  * There are a few places where cpumask_var_t isn't appropriate and
@@ -1068,6 +1088,8 @@ static inline const struct cpumask *get_
  * interface gives only a momentary snapshot and is not protected against
  * concurrent CPU hotplug operations unless invoked from a cpuhp_lock held
  * region.
+ *
+ * Return: momentary snapshot of the number of online CPUs
  */
 static __always_inline unsigned int num_online_cpus(void)
 {
@@ -1160,7 +1182,7 @@ static inline bool cpu_dying(unsigned in
  * @mask: the cpumask to copy
  * @buf: the buffer to copy into
  *
- * Returns the length of the (null-terminated) @buf string, zero if
+ * Return: the length of the (null-terminated) @buf string, zero if
  * nothing is copied.
  */
 static inline ssize_t
@@ -1183,7 +1205,7 @@ cpumap_print_to_pagebuf(bool list, char
  * cpumask; Typically used by bin_attribute to export cpumask bitmask
  * ABI.
  *
- * Returns the length of how many bytes have been copied, excluding
+ * Return: the length of how many bytes have been copied, excluding
  * terminating '\0'.
  */
 static inline ssize_t
@@ -1204,6 +1226,9 @@ cpumap_print_bitmask_to_buf(char *buf, c
  *
  * Everything is same with the above cpumap_print_bitmask_to_buf()
  * except the print format.
+ *
+ * Return: the length of how many bytes have been copied, excluding
+ * terminating '\0'.
  */
 static inline ssize_t
 cpumap_print_list_to_buf(char *buf, const struct cpumask *mask,
diff -- a/lib/cpumask.c b/lib/cpumask.c
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -14,7 +14,7 @@
  * @start: the start point of the iteration
  * @wrap: assume @n crossing @start terminates the iteration
  *
- * Returns >= nr_cpu_ids on completion
+ * Return: >= nr_cpu_ids on completion
  *
  * Note: the @wrap argument is required for the start condition when
  * we cannot assume @start is set in @mask.
@@ -48,8 +48,9 @@ EXPORT_SYMBOL(cpumask_next_wrap);
  * @node: memory node from which to allocate or %NUMA_NO_NODE
  *
  * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
- * a nop returning a constant 1 (in <linux/cpumask.h>)
- * Returns TRUE if memory allocation succeeded, FALSE otherwise.
+ * a nop returning a constant 1 (in <linux/cpumask.h>).
+ *
+ * Return: TRUE if memory allocation succeeded, FALSE otherwise.
  *
  * In addition, mask will be NULL if this fails.  Note that gcc is
  * usually smart enough to know that mask can never be NULL if
@@ -115,7 +116,7 @@ void __init free_bootmem_cpumask_var(cpu
  * @i: index number
  * @node: local numa_node
  *
- * Returns online CPU according to a numa aware policy; local cpus are returned
+ * Return: online CPU according to a numa aware policy; local cpus are returned
  * first, followed by non-local ones, then it wraps around.
  *
  * For those who wants to enumerate all CPUs based on their NUMA distances,
@@ -162,7 +163,7 @@ static DEFINE_PER_CPU(int, distribute_cp
  * Iterated calls using the same srcp1 and srcp2 will be distributed within
  * their intersection.
  *
- * Returns >= nr_cpu_ids if the intersection is empty.
+ * Return: >= nr_cpu_ids if the intersection is empty.
  */
 unsigned int cpumask_any_and_distribute(const struct cpumask *src1p,
 			       const struct cpumask *src2p)
@@ -181,6 +182,12 @@ unsigned int cpumask_any_and_distribute(
 }
 EXPORT_SYMBOL(cpumask_any_and_distribute);
 
+/**
+ * cpumask_any_distribute - Return an arbitrary cpu from srcp
+ * @srcp: &cpumask for selection
+ *
+ * Return: >= nr_cpu_ids if the intersection is empty.
+ */
 unsigned int cpumask_any_distribute(const struct cpumask *srcp)
 {
 	unsigned int next, prev;

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