[tip: locking/core] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

From: tip-bot2 for Waiman Long
Date: Wed Sep 11 2024 - 06:06:26 EST


The following commit has been merged into the locking/core branch of tip:

Commit-ID: d00b83d416e73bc3fa4d21b14bec920e88b70ce6
Gitweb: https://git.kernel.org/tip/d00b83d416e73bc3fa4d21b14bec920e88b70ce6
Author: Waiman Long <longman@xxxxxxxxxx>
AuthorDate: Mon, 09 Sep 2024 14:29:05 -04:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 10 Sep 2024 12:02:33 +02:00

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@xxxxxxxxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Tested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240909182905.161156-1-longman@xxxxxxxxxx
---
kernel/locking/rwsem.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 33cac79..4b041e9 100644
--- 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
@@ -266,15 +273,6 @@ 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)
-{
- 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.
*/