diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2025-09-08 18:00:02 -0700 |
|---|---|---|
| committer | Vlastimil Babka <vbabka@suse.cz> | 2025-09-29 09:42:35 +0200 |
| commit | 4957089a23f41f31f8e7e22802a8ef9f5789c191 (patch) | |
| tree | 9531b4ed88e7710247c3f494720298ecfd3b1d2a | |
| parent | 4ec1a08d20315d2d2a6f942ea563e5dadd988e98 (diff) | |
locking/local_lock: Introduce local_lock_is_locked().
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).
The goal is to detect a deadlock by the caller.
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
| -rw-r--r-- | include/linux/local_lock.h | 2 | ||||
| -rw-r--r-- | include/linux/local_lock_internal.h | 7 | ||||
| -rw-r--r-- | include/linux/rtmutex.h | 10 | ||||
| -rw-r--r-- | kernel/locking/rtmutex_common.h | 9 |
4 files changed, 19 insertions, 9 deletions
diff --git a/include/linux/local_lock.h b/include/linux/local_lock.h index 2ba846419524..0d91d060e3e9 100644 --- a/include/linux/local_lock.h +++ b/include/linux/local_lock.h @@ -66,6 +66,8 @@ */ #define local_trylock(lock) __local_trylock(this_cpu_ptr(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 949de37700db..a4dc479157b5 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 fa9f1021541e..ede4c6bf6f22 100644 --- a/include/linux/rtmutex.h +++ b/include/linux/rtmutex.h @@ -44,6 +44,16 @@ static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock) return READ_ONCE(lock->owner) != NULL; } +#ifdef CONFIG_RT_MUTEXES +#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); +} +#endif 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. |