locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
when `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 moving these two functions under the CONFIG_DEBUG_RWSEMS define.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240909182905.161156-1-longman@redhat.com

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 33cac79e3994602469ec71f2185eb1d6818e564e..4b041e9c408fee2e0e48417eaa6cee6cbd3af301 100644 (file)
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -181,12 +181,21 @@ static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
        __rwsem_set_reader_owned(sem, current);
 }
 
+#ifdef CONFIG_DEBUG_RWSEMS
+/*
+ * Return just the real task structure pointer of the owner
+ */
+static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+{
+       return (struct task_struct *)
+               (atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
 /*
  * Return true if the rwsem is owned by a reader.
  */
 static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 {
-#ifdef CONFIG_DEBUG_RWSEMS
        /*
         * Check the count to see if it is write-locked.
         */
@@ -194,11 +203,9 @@ static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 
        if (count & RWSEM_WRITER_MASK)
                return false;
-#endif
        return rwsem_test_oflags(sem, RWSEM_READER_OWNED);
 }
 
-#ifdef CONFIG_DEBUG_RWSEMS
 /*
  * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
  * is a task pointer in owner of a reader-owned rwsem, it will be the
@@ -265,15 +272,6 @@ static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
        return false;
 }
 
-/*
- * Return just the real task structure pointer of the owner
- */
-static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
-{
-       return (struct task_struct *)
-               (atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
-}
-
 /*
  * Return the real task structure pointer of the owner and the embedded
  * flags in the owner. pflags must be non-NULL.