| Date | Fri, 30 Jul 2021 15:50:34 +0200 | From | Thomas Gleixner <> | Subject | [patch 27/63] locking/spinlock: Provide RT specific spinlock type |
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From: Thomas Gleixner <tglx@linutronix.de>
RT replaces spinlocks with a simple wrapper around a rtmutex which turns spinlocks on RT into 'sleeping' spinlocks. The actual implementation of the spinlock API differs from a regular rtmutex as it does neither handle timeouts nor signals and it is state preserving accross the lock operation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- include/linux/spinlock_types.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) --- --- a/include/linux/spinlock_types.h +++ b/include/linux/spinlock_types.h @@ -51,6 +51,9 @@ #define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) +#ifndef CONFIG_PREEMPT_RT + +/* Non PREEMPT_RT kernels map spinlock to raw_spinlock */ typedef struct spinlock { union { struct raw_spinlock rlock; @@ -79,6 +82,29 @@ typedef struct spinlock { #define DEFINE_SPINLOCK(x) spinlock_t x = __SPIN_LOCK_UNLOCKED(x) +#else /* !CONFIG_PREEMPT_RT */ + +/* PREEMPT_RT kernels map spinlock to rt_mutex */ +#include <linux/rtmutex.h> + +typedef struct spinlock { + struct rt_mutex_base lock; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +} spinlock_t; + +#define __SPIN_LOCK_UNLOCKED(name) \ + { \ + .lock = __RT_MUTEX_BASE_INITIALIZER(name.lock), \ + SPIN_DEP_MAP_INIT(name) \ + } + +#define DEFINE_SPINLOCK(name) \ + spinlock_t name = __SPIN_LOCK_UNLOCKED(name) + +#endif /* CONFIG_PREEMPT_RT */ + #include <linux/rwlock_types.h> #endif /* __LINUX_SPINLOCK_TYPES_H */
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