Subject: [PATCH 4/4] locking/rt: Annotate unlock followed by lock for sparse.
From: Sebastian Andrzej Siewior <[email-masked]>
Date: Mon, 12 Aug 2024 12:39:05 +0200

rt_mutex_slowlock_block() and rtlock_slowlock_locked() both unlock
lock::wait_lock and then lock it later. This is unusual and sparse
complains about it.

Add __releases() + __acquires() annotation to mark that it is expected.

Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Sebastian Andrzej Siewior <[email-masked]>
---
 kernel/locking/rtmutex.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1601,6 +1601,7 @@ static int __sched rt_mutex_slowlock_blo
 					   unsigned int state,
 					   struct hrtimer_sleeper *timeout,
 					   struct rt_mutex_waiter *waiter)
+	__releases(&lock->wait_lock) __acquires(&lock->wait_lock)
 {
 	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
 	struct task_struct *owner;
@@ -1805,6 +1806,7 @@ static __always_inline int __rt_mutex_lo
  * @lock:	The underlying RT mutex
  */
 static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock)
+	__releases(&lock->wait_lock) __acquires(&lock->wait_lock)
 {
 	struct rt_mutex_waiter waiter;
 	struct task_struct *owner;