^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0-or-later */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Queued spinlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * (C) Copyright 2015 Hewlett-Packard Enterprise Development LP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Authors: Waiman Long <waiman.long@hpe.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #ifndef __ASM_GENERIC_QSPINLOCK_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #define __ASM_GENERIC_QSPINLOCK_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <asm-generic/qspinlock_types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/atomic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #ifndef queued_spin_is_locked
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * queued_spin_is_locked - is the spinlock locked?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * @lock: Pointer to queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * Return: 1 if it is locked, 0 otherwise
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * Any !0 state indicates it is locked, even if _Q_LOCKED_VAL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * isn't immediately observable.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) return atomic_read(&lock->val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * queued_spin_value_unlocked - is the spinlock structure unlocked?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * @lock: queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * Return: 1 if it is unlocked, 0 otherwise
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * N.B. Whenever there are tasks waiting for the lock, it is considered
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * locked wrt the lockref code to avoid lock stealing by the lockref
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * code and change things underneath the lock. This also allows some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * optimizations to be applied without conflict with lockref.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) static __always_inline int queued_spin_value_unlocked(struct qspinlock lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) return !atomic_read(&lock.val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * queued_spin_is_contended - check if the lock is contended
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * @lock : Pointer to queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * Return: 1 if lock contended, 0 otherwise
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) static __always_inline int queued_spin_is_contended(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) return atomic_read(&lock->val) & ~_Q_LOCKED_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * queued_spin_trylock - try to acquire the queued spinlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * @lock : Pointer to queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * Return: 1 if lock acquired, 0 if failed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) static __always_inline int queued_spin_trylock(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) u32 val = atomic_read(&lock->val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) if (unlikely(val))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) return likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) extern void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) #ifndef queued_spin_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) * queued_spin_lock - acquire a queued spinlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) * @lock: Pointer to queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) static __always_inline void queued_spin_lock(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) u32 val = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) if (likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) queued_spin_lock_slowpath(lock, val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) #ifndef queued_spin_unlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * queued_spin_unlock - release a queued spinlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) * @lock : Pointer to queued spinlock structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) static __always_inline void queued_spin_unlock(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) * unlock() needs release semantics:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) smp_store_release(&lock->locked, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) #ifndef virt_spin_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) static __always_inline bool virt_spin_lock(struct qspinlock *lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) * Remapping spinlock architecture specific functions to the corresponding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) * queued spinlock functions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #define arch_spin_is_locked(l) queued_spin_is_locked(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) #define arch_spin_is_contended(l) queued_spin_is_contended(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) #define arch_spin_value_unlocked(l) queued_spin_value_unlocked(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) #define arch_spin_lock(l) queued_spin_lock(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) #define arch_spin_trylock(l) queued_spin_trylock(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) #define arch_spin_unlock(l) queued_spin_unlock(l)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) #endif /* __ASM_GENERIC_QSPINLOCK_H */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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