Provide the actual locking functions which make use of the general and spinlock specific rtmutex code.
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| @@ -25,6 +25,7 @@ obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o · 24 unmodified lines | |||
| 25 | obj-$(CONFIG_PROVE_LOCKING) += spinlock.o | 25 | obj-$(CONFIG_PROVE_LOCKING) += spinlock.o |
| 26 | obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o | 26 | obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o |
| 27 | obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o | 27 | obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o |
| 28 | obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o | ||
| 28 | obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o | 29 | obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o |
| 29 | obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o | 30 | obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o |
| 30 | obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o | 31 | obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o |
| @@ -0,0 +1,129 @@ | |||
| 1 | // SPDX-License-Identifier: GPL-2.0-only | ||
| 2 | /* | ||
| 3 | * PREEMPT_RT substitution for spin/rw_locks | ||
| 4 | * | ||
| 5 | * spinlocks and rwlocks on RT are based on rtmutexes, with a few twists to | ||
| 6 | * resemble the non RT semantics: | ||
| 7 | * | ||
| 8 | * - Contrary to plain rtmutexes, spinlocks and rwlocks are state | ||
| 9 | * preserving. The task state is saved before blocking on the underlying | ||
| 10 | * rtmutex, and restored when the lock has been acquired. Regular wakeups | ||
| 11 | * during that time are redirected to the saved state so no wake up is | ||
| 12 | * missed. | ||
| 13 | * | ||
| 14 | * - Non RT spin/rwlocks disable preemption and eventually interrupts. | ||
| 15 | * Disabling preemption has the side effect of disabling migration and | ||
| 16 | * preventing RCU grace periods. | ||
| 17 | * | ||
| 18 | * The RT substitutions explicitly disable migration and take | ||
| 19 | * rcu_read_lock() across the lock held section. | ||
| 20 | */ | ||
| 21 | #include <linux/spinlock.h> | ||
| 22 | #include <linux/export.h> | ||
| 23 | |||
| 24 | #define RT_MUTEX_BUILD_SPINLOCKS | ||
| 25 | #include "rtmutex.c" | ||
| 26 | |||
| 27 | static __always_inline void rtlock_lock(struct rt_mutex_base *rtm) | ||
| 28 | { | ||
| 29 | if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current))) | ||
| 30 | rtlock_slowlock(rtm); | ||
| 31 | } | ||
| 32 | |||
| 33 | static __always_inline void __rt_spin_lock(spinlock_t *lock) | ||
| 34 | { | ||
| 35 | ___might_sleep(__FILE__, __LINE__, 0); | ||
| 36 | rtlock_lock(&lock->lock); | ||
| 37 | rcu_read_lock(); | ||
| 38 | migrate_disable(); | ||
| 39 | } | ||
| 40 | |||
| 41 | void __sched rt_spin_lock(spinlock_t *lock) | ||
| 42 | { | ||
| 43 | spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); | ||
| 44 | __rt_spin_lock(lock); | ||
| 45 | } | ||
| 46 | EXPORT_SYMBOL(rt_spin_lock); | ||
| 47 | |||
| 48 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | ||
| 49 | void __sched rt_spin_lock_nested(spinlock_t *lock, int subclass) | ||
| 50 | { | ||
| 51 | spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); | ||
| 52 | __rt_spin_lock(lock); | ||
| 53 | } | ||
| 54 | EXPORT_SYMBOL(rt_spin_lock_nested); | ||
| 55 | |||
| 56 | void __sched rt_spin_lock_nest_lock(spinlock_t *lock, | ||
| 57 | struct lockdep_map *nest_lock) | ||
| 58 | { | ||
| 59 | spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); | ||
| 60 | __rt_spin_lock(lock); | ||
| 61 | } | ||
| 62 | EXPORT_SYMBOL(rt_spin_lock_nest_lock); | ||
| 63 | #endif | ||
| 64 | |||
| 65 | void __sched rt_spin_unlock(spinlock_t *lock) | ||
| 66 | { | ||
| 67 | spin_release(&lock->dep_map, _RET_IP_); | ||
| 68 | migrate_enable(); | ||
| 69 | rcu_read_unlock(); | ||
| 70 | |||
| 71 | if (unlikely(!rt_mutex_cmpxchg_release(&lock->lock, current, NULL))) | ||
| 72 | rt_mutex_slowunlock(&lock->lock); | ||
| 73 | } | ||
| 74 | EXPORT_SYMBOL(rt_spin_unlock); | ||
| 75 | |||
| 76 | /* | ||
| 77 | * Wait for the lock to get unlocked: instead of polling for an unlock | ||
| 78 | * (like raw spinlocks do), lock and unlock, to force the kernel to | ||
| 79 | * schedule if there's contention: | ||
| 80 | */ | ||
| 81 | void __sched rt_spin_lock_unlock(spinlock_t *lock) | ||
| 82 | { | ||
| 83 | spin_lock(lock); | ||
| 84 | spin_unlock(lock); | ||
| 85 | } | ||
| 86 | EXPORT_SYMBOL(rt_spin_lock_unlock); | ||
| 87 | |||
| 88 | static __always_inline int __rt_spin_trylock(spinlock_t *lock) | ||
| 89 | { | ||
| 90 | int ret = 1; | ||
| 91 | |||
| 92 | if (unlikely(!rt_mutex_cmpxchg_acquire(&lock->lock, NULL, current))) | ||
| 93 | ret = rt_mutex_slowtrylock(&lock->lock); | ||
| 94 | |||
| 95 | if (ret) { | ||
| 96 | spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); | ||
| 97 | rcu_read_lock(); | ||
| 98 | migrate_disable(); | ||
| 99 | } | ||
| 100 | return ret; | ||
| 101 | } | ||
| 102 | |||
| 103 | int __sched rt_spin_trylock(spinlock_t *lock) | ||
| 104 | { | ||
| 105 | return __rt_spin_trylock(lock); | ||
| 106 | } | ||
| 107 | EXPORT_SYMBOL(rt_spin_trylock); | ||
| 108 | |||
| 109 | int __sched rt_spin_trylock_bh(spinlock_t *lock) | ||
| 110 | { | ||
| 111 | int ret; | ||
| 112 | |||
| 113 | local_bh_disable(); | ||
| 114 | ret = __rt_spin_trylock(lock); | ||
| 115 | if (!ret) | ||
| 116 | local_bh_enable(); | ||
| 117 | return ret; | ||
| 118 | } | ||
| 119 | EXPORT_SYMBOL(rt_spin_trylock_bh); | ||
| 120 | |||
| 121 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | ||
| 122 | void __rt_spin_lock_init(spinlock_t *lock, const char *name, | ||
| 123 | struct lock_class_key *key) | ||
| 124 | { | ||
| 125 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); | ||
| 126 | lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG); | ||
| 127 | } | ||
| 128 | EXPORT_SYMBOL(__rt_spin_lock_init); | ||
| 129 | #endif | ||