Merge tag 'docs-4.15' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A relatively calm cycle for the docs tree again.

  - The old driver statement has been added to the kernel docs.

  - We have a couple of new helper scripts. find-unused-docs.sh from
    Sayli Karnic will point out kerneldoc comments that are not actually
    used in the documentation. Jani Nikula's
    documentation-file-ref-check finds references to non-existing files.

  - A new ftrace document from Steve Rostedt.

  - Vinod Koul converted the dmaengine docs to RST

  Beyond that, it's mostly simple fixes.

  This set reaches outside of Documentation/ a bit more than most. In
  all cases, the changes are to comment docs, mostly from Randy, in
  places where there didn't seem to be anybody better to take them"

* tag 'docs-4.15' of git://git.lwn.net/linux: (52 commits)
  documentation: fb: update list of available compiled-in fonts
  MAINTAINERS: update DMAengine documentation location
  dmaengine: doc: ReSTize pxa_dma doc
  dmaengine: doc: ReSTize dmatest doc
  dmaengine: doc: ReSTize client API doc
  dmaengine: doc: ReSTize provider doc
  dmaengine: doc: Add ReST style dmaengine document
  ftrace/docs: Add documentation on how to use ftrace from within the kernel
  bug-hunting.rst: Fix an example and a typo in a Sphinx tag
  scripts: Add a script to find unused documentation
  samples: Convert timers to use timer_setup()
  documentation: kernel-api: add more info on bitmap functions
  Documentation: fix selftests related file refs
  Documentation: fix ref to power basic-pm-debugging
  Documentation: fix ref to trace stm content
  Documentation: fix ref to coccinelle content
  Documentation: fix ref to workqueue content
  Documentation: fix ref to sphinx/kerneldoc.py
  Documentation: fix locking rt-mutex doc refs
  docs: dev-tools: correct Coccinelle version number
  ...

4 files changed, 126 insertions, 71 deletions

diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
index d2013064dc69..dc9726fdac8f 100644
--- a/include/asm-generic/div64.h
+++ b/include/asm-generic/div64.h
@@ -26,6 +26,20 @@
 
 #if BITS_PER_LONG == 64
 
+/**
+ * do_div - returns 2 values: calculate remainder and update new dividend
+ * @n: pointer to uint64_t dividend (will be updated)
+ * @base: uint32_t divisor
+ *
+ * Summary:
+ * ``uint32_t remainder = *n % base;``
+ * ``*n = *n / base;``
+ *
+ * Return: (uint32_t)remainder
+ *
+ * NOTE: macro parameter @n is evaluated multiple times,
+ * beware of side effects!
+ */
 # define do_div(n,base) ({					\
 	uint32_t __base = (base);				\
 	uint32_t __rem;						\
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 19748a5b0e77..3489253e38fc 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -22,65 +22,74 @@
  * See lib/bitmap.c for more details.
  */
 
-/*
+/**
+ * DOC: bitmap overview
+ *
  * The available bitmap operations and their rough meaning in the
  * case that the bitmap is a single unsigned long are thus:
  *
  * Note that nbits should be always a compile time evaluable constant.
  * Otherwise many inlines will generate horrible code.
  *
- * bitmap_zero(dst, nbits)			*dst = 0UL
- * bitmap_fill(dst, nbits)			*dst = ~0UL
- * bitmap_copy(dst, src, nbits)			*dst = *src
- * bitmap_and(dst, src1, src2, nbits)		*dst = *src1 & *src2
- * bitmap_or(dst, src1, src2, nbits)		*dst = *src1 | *src2
- * bitmap_xor(dst, src1, src2, nbits)		*dst = *src1 ^ *src2
- * bitmap_andnot(dst, src1, src2, nbits)	*dst = *src1 & ~(*src2)
- * bitmap_complement(dst, src, nbits)		*dst = ~(*src)
- * bitmap_equal(src1, src2, nbits)		Are *src1 and *src2 equal?
- * bitmap_intersects(src1, src2, nbits) 	Do *src1 and *src2 overlap?
- * bitmap_subset(src1, src2, nbits)		Is *src1 a subset of *src2?
- * bitmap_empty(src, nbits)			Are all bits zero in *src?
- * bitmap_full(src, nbits)			Are all bits set in *src?
- * bitmap_weight(src, nbits)			Hamming Weight: number set bits
- * bitmap_set(dst, pos, nbits)			Set specified bit area
- * bitmap_clear(dst, pos, nbits)		Clear specified bit area
- * bitmap_find_next_zero_area(buf, len, pos, n, mask)	Find bit free area
- * bitmap_find_next_zero_area_off(buf, len, pos, n, mask)	as above
- * bitmap_shift_right(dst, src, n, nbits)	*dst = *src >> n
- * bitmap_shift_left(dst, src, n, nbits)	*dst = *src << n
- * bitmap_remap(dst, src, old, new, nbits)	*dst = map(old, new)(src)
- * bitmap_bitremap(oldbit, old, new, nbits)	newbit = map(old, new)(oldbit)
- * bitmap_onto(dst, orig, relmap, nbits)	*dst = orig relative to relmap
- * bitmap_fold(dst, orig, sz, nbits)		dst bits = orig bits mod sz
- * bitmap_parse(buf, buflen, dst, nbits)	Parse bitmap dst from kernel buf
- * bitmap_parse_user(ubuf, ulen, dst, nbits)	Parse bitmap dst from user buf
- * bitmap_parselist(buf, dst, nbits)		Parse bitmap dst from kernel buf
- * bitmap_parselist_user(buf, dst, nbits)	Parse bitmap dst from user buf
- * bitmap_find_free_region(bitmap, bits, order)	Find and allocate bit region
- * bitmap_release_region(bitmap, pos, order)	Free specified bit region
- * bitmap_allocate_region(bitmap, pos, order)	Allocate specified bit region
- * bitmap_from_u32array(dst, nbits, buf, nwords) *dst = *buf (nwords 32b words)
- * bitmap_to_u32array(buf, nwords, src, nbits)	*buf = *dst (nwords 32b words)
+ * ::
+ *
+ *  bitmap_zero(dst, nbits)                     *dst = 0UL
+ *  bitmap_fill(dst, nbits)                     *dst = ~0UL
+ *  bitmap_copy(dst, src, nbits)                *dst = *src
+ *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 & *src2
+ *  bitmap_or(dst, src1, src2, nbits)           *dst = *src1 | *src2
+ *  bitmap_xor(dst, src1, src2, nbits)          *dst = *src1 ^ *src2
+ *  bitmap_andnot(dst, src1, src2, nbits)       *dst = *src1 & ~(*src2)
+ *  bitmap_complement(dst, src, nbits)          *dst = ~(*src)
+ *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
+ *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
+ *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
+ *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
+ *  bitmap_full(src, nbits)                     Are all bits set in *src?
+ *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
+ *  bitmap_set(dst, pos, nbits)                 Set specified bit area
+ *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
+ *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
+ *  bitmap_find_next_zero_area_off(buf, len, pos, n, mask)  as above
+ *  bitmap_shift_right(dst, src, n, nbits)      *dst = *src >> n
+ *  bitmap_shift_left(dst, src, n, nbits)       *dst = *src << n
+ *  bitmap_remap(dst, src, old, new, nbits)     *dst = map(old, new)(src)
+ *  bitmap_bitremap(oldbit, old, new, nbits)    newbit = map(old, new)(oldbit)
+ *  bitmap_onto(dst, orig, relmap, nbits)       *dst = orig relative to relmap
+ *  bitmap_fold(dst, orig, sz, nbits)           dst bits = orig bits mod sz
+ *  bitmap_parse(buf, buflen, dst, nbits)       Parse bitmap dst from kernel buf
+ *  bitmap_parse_user(ubuf, ulen, dst, nbits)   Parse bitmap dst from user buf
+ *  bitmap_parselist(buf, dst, nbits)           Parse bitmap dst from kernel buf
+ *  bitmap_parselist_user(buf, dst, nbits)      Parse bitmap dst from user buf
+ *  bitmap_find_free_region(bitmap, bits, order)  Find and allocate bit region
+ *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
+ *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region
+ *  bitmap_from_u32array(dst, nbits, buf, nwords)  *dst = *buf (nwords 32b words)
+ *  bitmap_to_u32array(buf, nwords, src, nbits) *buf = *dst (nwords 32b words)
+ *
  */
 
-/*
- * Also the following operations in asm/bitops.h apply to bitmaps.
+/**
+ * DOC: bitmap bitops
+ *
+ * Also the following operations in asm/bitops.h apply to bitmaps.::
+ *
+ *  set_bit(bit, addr)                  *addr |= bit
+ *  clear_bit(bit, addr)                *addr &= ~bit
+ *  change_bit(bit, addr)               *addr ^= bit
+ *  test_bit(bit, addr)                 Is bit set in *addr?
+ *  test_and_set_bit(bit, addr)         Set bit and return old value
+ *  test_and_clear_bit(bit, addr)       Clear bit and return old value
+ *  test_and_change_bit(bit, addr)      Change bit and return old value
+ *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
+ *  find_first_bit(addr, nbits)         Position first set bit in *addr
+ *  find_next_zero_bit(addr, nbits, bit)  Position next zero bit in *addr >= bit
+ *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit
  *
- * set_bit(bit, addr)			*addr |= bit
- * clear_bit(bit, addr)			*addr &= ~bit
- * change_bit(bit, addr)		*addr ^= bit
- * test_bit(bit, addr)			Is bit set in *addr?
- * test_and_set_bit(bit, addr)		Set bit and return old value
- * test_and_clear_bit(bit, addr)	Clear bit and return old value
- * test_and_change_bit(bit, addr)	Change bit and return old value
- * find_first_zero_bit(addr, nbits)	Position first zero bit in *addr
- * find_first_bit(addr, nbits)		Position first set bit in *addr
- * find_next_zero_bit(addr, nbits, bit)	Position next zero bit in *addr >= bit
- * find_next_bit(addr, nbits, bit)	Position next set bit in *addr >= bit
  */
 
-/*
+/**
+ * DOC: declare bitmap
  * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
  * to declare an array named 'name' of just enough unsigned longs to
  * contain all bit positions from 0 to 'bits' - 1.
@@ -361,8 +370,9 @@ static inline int bitmap_parse(const char *buf, unsigned int buflen,
 	return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
 }
 
-/*
+/**
  * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
+ * @n: u64 value
  *
  * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
  * integers in 32-bit environment, and 64-bit integers in 64-bit one.
@@ -393,14 +403,14 @@ static inline int bitmap_parse(const char *buf, unsigned int buflen,
 				((unsigned long) ((u64)(n) >> 32))
 #endif
 
-/*
+/**
  * bitmap_from_u64 - Check and swap words within u64.
  *  @mask: source bitmap
  *  @dst:  destination bitmap
  *
- * In 32-bit Big Endian kernel, when using (u32 *)(&val)[*]
+ * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
  * to read u64 mask, we will get the wrong word.
- * That is "(u32 *)(&val)[0]" gets the upper 32 bits,
+ * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
  * but we expect the lower 32-bits of u64.
  */
 static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
diff --git a/include/linux/log2.h b/include/linux/log2.h
index c373295f359f..41a1ae010993 100644
--- a/include/linux/log2.h
+++ b/include/linux/log2.h
@@ -37,19 +37,23 @@ int __ilog2_u64(u64 n)
 }
 #endif
 
-/*
- *  Determine whether some value is a power of two, where zero is
+/**
+ * is_power_of_2() - check if a value is a power of two
+ * @n: the value to check
+ *
+ * Determine whether some value is a power of two, where zero is
  * *not* considered a power of two.
+ * Return: true if @n is a power of 2, otherwise false.
  */
-
 static inline __attribute__((const))
 bool is_power_of_2(unsigned long n)
 {
 	return (n != 0 && ((n & (n - 1)) == 0));
 }
 
-/*
- * round up to nearest power of two
+/**
+ * __roundup_pow_of_two() - round up to nearest power of two
+ * @n: value to round up
  */
 static inline __attribute__((const))
 unsigned long __roundup_pow_of_two(unsigned long n)
@@ -57,8 +61,9 @@ unsigned long __roundup_pow_of_two(unsigned long n)
 	return 1UL << fls_long(n - 1);
 }
 
-/*
- * round down to nearest power of two
+/**
+ * __rounddown_pow_of_two() - round down to nearest power of two
+ * @n: value to round down
  */
 static inline __attribute__((const))
 unsigned long __rounddown_pow_of_two(unsigned long n)
@@ -67,12 +72,12 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 }
 
 /**
- * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
- * @n - parameter
+ * ilog2 - log base 2 of 32-bit or a 64-bit unsigned value
+ * @n: parameter
  *
  * constant-capable log of base 2 calculation
  * - this can be used to initialise global variables from constant data, hence
- *   the massive ternary operator construction
+ * the massive ternary operator construction
  *
  * selects the appropriately-sized optimised version depending on sizeof(n)
  */
@@ -150,7 +155,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 
 /**
  * roundup_pow_of_two - round the given value up to nearest power of two
- * @n - parameter
+ * @n: parameter
  *
  * round the given value up to the nearest power of two
  * - the result is undefined when n == 0
@@ -167,7 +172,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 
 /**
  * rounddown_pow_of_two - round the given value down to nearest power of two
- * @n - parameter
+ * @n: parameter
  *
  * round the given value down to the nearest power of two
  * - the result is undefined when n == 0
@@ -180,6 +185,12 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
 	__rounddown_pow_of_two(n)		\
  )
 
+static inline __attribute_const__
+int __order_base_2(unsigned long n)
+{
+	return n > 1 ? ilog2(n - 1) + 1 : 0;
+}
+
 /**
  * order_base_2 - calculate the (rounded up) base 2 order of the argument
  * @n: parameter
@@ -193,13 +204,6 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
  *  ob2(5) = 3
  *  ... and so on.
  */
-
-static inline __attribute_const__
-int __order_base_2(unsigned long n)
-{
-	return n > 1 ? ilog2(n - 1) + 1 : 0;
-}
-
 #define order_base_2(n)				\
 (						\
 	__builtin_constant_p(n) ? (		\
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 082de345b73c..837f2f2d1d34 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -12,6 +12,11 @@
 
 /**
  * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 32bit divisor
+ * @remainder: pointer to unsigned 32bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
  *
  * This is commonly provided by 32bit archs to provide an optimized 64bit
  * divide.
@@ -24,6 +29,11 @@ static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
 
 /**
  * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 32bit divisor
+ * @remainder: pointer to signed 32bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
  */
 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
 {
@@ -33,6 +43,11 @@ static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
 
 /**
  * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 64bit divisor
+ * @remainder: pointer to unsigned 64bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
  */
 static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
 {
@@ -42,6 +57,10 @@ static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
 
 /**
  * div64_u64 - unsigned 64bit divide with 64bit divisor
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 64bit divisor
+ *
+ * Return: dividend / divisor
  */
 static inline u64 div64_u64(u64 dividend, u64 divisor)
 {
@@ -50,6 +69,10 @@ static inline u64 div64_u64(u64 dividend, u64 divisor)
 
 /**
  * div64_s64 - signed 64bit divide with 64bit divisor
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 64bit divisor
+ *
+ * Return: dividend / divisor
  */
 static inline s64 div64_s64(s64 dividend, s64 divisor)
 {
@@ -89,6 +112,8 @@ extern s64 div64_s64(s64 dividend, s64 divisor);
 
 /**
  * div_u64 - unsigned 64bit divide with 32bit divisor
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 32bit divisor
  *
  * This is the most common 64bit divide and should be used if possible,
  * as many 32bit archs can optimize this variant better than a full 64bit
@@ -104,6 +129,8 @@ static inline u64 div_u64(u64 dividend, u32 divisor)
 
 /**
  * div_s64 - signed 64bit divide with 32bit divisor
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 32bit divisor
  */
 #ifndef div_s64
 static inline s64 div_s64(s64 dividend, s32 divisor)