find: Switch from inline to __always_inline

'inline' keyword is only a recommendation for compiler. If it decides to
not inline find_bit nodemask functions, the whole small_const_nbits()
machinery doesn't work.

This is how a standard GCC 11.3.0 does for my x86_64 build now. This patch
replaces 'inline' directive with unconditional '__always_inline' to make
sure that there's always a chance for compile-time optimization. It doesn't
change size of kernel image, according to bloat-o-meter.

[[ Brian: split out from:
Subject: [PATCH 1/3] bitmap: switch from inline to __always_inline
https://lore.kernel.org/all/[e-mail]/
But rewritten, as there were too many conflicts. ]]

Co-developed-by: Brian Norris <[e-mail]>
Signed-off-by: Brian Norris <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Nathan Chancellor <[e-mail]>
Signed-off-by: Yury Norov <[e-mail]>

include/linux/find.h

···
  * Returns the bit number for the next set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
 			    unsigned long offset)
 {
···
  * Returns the bit number for the next set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_and_bit(const unsigned long *addr1,
 		const unsigned long *addr2, unsigned long size,
 		unsigned long offset)
···
  * Returns the bit number for the next set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_andnot_bit(const unsigned long *addr1,
 		const unsigned long *addr2, unsigned long size,
 		unsigned long offset)
···
  * Returns the bit number for the next set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_or_bit(const unsigned long *addr1,
 		const unsigned long *addr2, unsigned long size,
 		unsigned long offset)
···
  * Returns the bit number of the next zero bit
  * If no bits are zero, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
 				 unsigned long offset)
 {
···
  * Returns the bit number of the first set bit.
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
 {
 	if (small_const_nbits(size)) {
···
  * Returns the bit number of the N'th set bit.
  * If no such, returns >= @size.
  */
-static inline
+static __always_inline
 unsigned long find_nth_bit(const unsigned long *addr, unsigned long size, unsigned long n)
 {
 	if (n >= size)
···
  * Returns the bit number of the N'th set bit.
  * If no such, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_nth_and_bit(const unsigned long *addr1, const unsigned long *addr2,
 				unsigned long size, unsigned long n)
 {
···
  * Returns the bit number of the N'th set bit.
  * If no such, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
 				unsigned long size, unsigned long n)
 {
···
  * Returns the bit number for the next set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_first_and_bit(const unsigned long *addr1,
 				 const unsigned long *addr2,
 				 unsigned long size)
···
  * Returns the bit number for the first set bit
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_first_and_and_bit(const unsigned long *addr1,
 				     const unsigned long *addr2,
 				     const unsigned long *addr3,
···
  * Returns the bit number of the first cleared bit.
  * If no bits are zero, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
 {
 	if (small_const_nbits(size)) {
···
  *
  * Returns the bit number of the last set bit, or size.
  */
-static inline
+static __always_inline
 unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
 {
 	if (small_const_nbits(size)) {
···
  * Returns the bit number for the next set bit, or first set bit up to @offset
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_and_bit_wrap(const unsigned long *addr1,
 					const unsigned long *addr2,
 					unsigned long size, unsigned long offset)
···
  * Returns the bit number for the next set bit, or first set bit up to @offset
  * If no bits are set, returns @size.
  */
-static inline
+static __always_inline
 unsigned long find_next_bit_wrap(const unsigned long *addr,
 					unsigned long size, unsigned long offset)
 {
···
  * Helper for for_each_set_bit_wrap(). Make sure you're doing right thing
  * before using it alone.
  */
-static inline
+static __always_inline
 unsigned long __for_each_wrap(const unsigned long *bitmap, unsigned long size,
 				 unsigned long start, unsigned long n)
 {
···
 
 #if defined(__LITTLE_ENDIAN)
 
-static inline unsigned long find_next_zero_bit_le(const void *addr,
-		unsigned long size, unsigned long offset)
+static __always_inline
+unsigned long find_next_zero_bit_le(const void *addr, unsigned long size, unsigned long offset)
 {
 	return find_next_zero_bit(addr, size, offset);
 }
 
-static inline unsigned long find_next_bit_le(const void *addr,
-		unsigned long size, unsigned long offset)
+static __always_inline
+unsigned long find_next_bit_le(const void *addr, unsigned long size, unsigned long offset)
 {
 	return find_next_bit(addr, size, offset);
 }
 
-static inline unsigned long find_first_zero_bit_le(const void *addr,
-		unsigned long size)
+static __always_inline
+unsigned long find_first_zero_bit_le(const void *addr, unsigned long size)
 {
 	return find_first_zero_bit(addr, size);
 }
···
 #elif defined(__BIG_ENDIAN)
 
 #ifndef find_next_zero_bit_le
-static inline
+static __always_inline
 unsigned long find_next_zero_bit_le(const void *addr, unsigned
 		long size, unsigned long offset)
 {
···
 #endif
 
 #ifndef find_first_zero_bit_le
-static inline
+static __always_inline
 unsigned long find_first_zero_bit_le(const void *addr, unsigned long size)
 {
 	if (small_const_nbits(size)) {
···
 #endif
 
 #ifndef find_next_bit_le
-static inline
+static __always_inline
 unsigned long find_next_bit_le(const void *addr, unsigned
 		long size, unsigned long offset)
 {