linux-kernel - [tip: locking/core] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG

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Message-ID: <172604917670.2215.16033363773535605001.tip-bot2@tip-bot2>
Date: Wed, 11 Sep 2024 10:06:16 -0000
From: "tip-bot2 for Waiman Long" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
 Waiman Long <longman@...hat.com>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: locking/core] locking/rwsem: Move is_rwsem_reader_owned() and
 rwsem_owner() under CONFIG_DEBUG_RWSEMS

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@...hat.com>
AuthorDate:    Mon, 09 Sep 2024 14:29:05 -04:00
Committer:     Peter Zijlstra <peterz@...radead.org>
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@...ux.intel.com>
Signed-off-by: Waiman Long <longman@...hat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Link: https://lore.kernel.org/r/20240909182905.161156-1-longman@redhat.com
---
 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.
  */