From: Alexei Starovoitov <ast@xxxxxxxxxx>
Introduce local_lock_is_locked() that returns true when
given local_lock is locked by current cpu (in !PREEMPT_RT) or
by current task (in PREEMPT_RT).
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
include/linux/local_lock.h | 2 ++
include/linux/local_lock_internal.h | 7 +++++++
include/linux/rtmutex.h | 9 +++++++++
kernel/locking/rtmutex_common.h | 9 ---------
4 files changed, 18 insertions(+), 9 deletions(-)
diff --git a/include/linux/local_lock.h b/include/linux/local_lock.h
index 16a2ee4f8310..092ce89b162a 100644
--- a/include/linux/local_lock.h
+++ b/include/linux/local_lock.h
@@ -66,6 +66,8 @@
*/
#define local_trylock(lock) __local_trylock(lock)
+#define local_lock_is_locked(lock) __local_lock_is_locked(lock)
+
/**
* local_trylock_irqsave - Try to acquire a per CPU local lock, save and disable
* interrupts if acquired
diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index 85c2e1b1af6b..db61409f040c 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -165,6 +165,9 @@ do { \
!!tl; \
})
+/* preemption or migration must be disabled before calling __local_lock_is_locked */
+#define __local_lock_is_locked(lock) READ_ONCE(this_cpu_ptr(lock)->acquired)
+
#define __local_lock_release(lock) \
do { \
local_trylock_t *tl; \
@@ -285,4 +288,8 @@ do { \
__local_trylock(lock); \
})
+/* migration must be disabled before calling __local_lock_is_locked */
+#define __local_lock_is_locked(__lock) \
+ (rt_mutex_owner(&this_cpu_ptr(__lock)->lock) == current)
+
#endif /* CONFIG_PREEMPT_RT */
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 7d049883a08a..a8f2fe154487 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -44,6 +44,15 @@ static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock)
return READ_ONCE(lock->owner) != NULL;
}
+#define RT_MUTEX_HAS_WAITERS 1UL
+
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
+{
+ unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
+
+ return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
+}
+
extern void rt_mutex_base_init(struct rt_mutex_base *rtb);
/**
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 78dd3d8c6554..cf6ddd1b23a2 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -153,15 +153,6 @@ static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
pi_tree.entry);
}
-#define RT_MUTEX_HAS_WAITERS 1UL
-
-static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
-{
- unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
-
- return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
-}
-
/*
* Constants for rt mutex functions which have a selectable deadlock
* detection.
--
2.47.1
