Commit d00b83d4 authored by Waiman Long's avatar Waiman Long Committed by Peter Zijlstra
Browse files

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: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240909182905.161156-1-longman@redhat.com
parent 39dea484

kernel/locking/rwsem.c

+10 −12
Original line number Diff line number Diff line
@@ -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.