[PATCH v1 1/1] locking/rwsem: Mark inline helpers with __maybe_unused

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

When one or more inline heplers are unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
  187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
      |                    ^~~~~~~~~~~~~~~~~~~~~
kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
  271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
      |                                   ^~~~~~~~~~~

Fix this by marking inline helpers with __maybe_unused.

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 kernel/locking/rwsem.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 33cac79e3994..c098567e2c68 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -184,7 +184,7 @@ static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
 /*
  * Return true if the rwsem is owned by a reader.
  */
-static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+static inline __maybe_unused bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 {
 #ifdef CONFIG_DEBUG_RWSEMS
 	/*
@@ -268,7 +268,7 @@ static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
 /*
  * Return just the real task structure pointer of the owner
  */
-static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+static inline __maybe_unused struct task_struct *rwsem_owner(struct rw_semaphore *sem)
 {
 	return (struct task_struct *)
 		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
@@ -1508,7 +1508,7 @@ static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
 {
 }
 
-static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+static inline __maybe_unused bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 {
 	int count = atomic_read(&sem->rwbase.readers);
 
-- 
2.43.0.rc1.1336.g36b5255a03ac