42 lines
834 B
C
42 lines
834 B
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_LOONGARCH_QSPINLOCK_H
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#define _ASM_LOONGARCH_QSPINLOCK_H
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#include <linux/jump_label.h>
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#ifdef CONFIG_PARAVIRT
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DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key);
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#define virt_spin_lock virt_spin_lock
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static inline bool virt_spin_lock(struct qspinlock *lock)
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{
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int val;
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if (!static_branch_unlikely(&virt_spin_lock_key))
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return false;
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/*
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* On hypervisors without PARAVIRT_SPINLOCKS support we fall
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* back to a Test-and-Set spinlock, because fair locks have
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* horrible lock 'holder' preemption issues.
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*/
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__retry:
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val = atomic_read(&lock->val);
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if (val || !atomic_try_cmpxchg(&lock->val, &val, _Q_LOCKED_VAL)) {
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cpu_relax();
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goto __retry;
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}
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return true;
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}
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#endif /* CONFIG_PARAVIRT */
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#include <asm-generic/qspinlock.h>
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#endif // _ASM_LOONGARCH_QSPINLOCK_H
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