diff options
Diffstat (limited to 'arch/loongarch/include/asm/qspinlock.h')
| -rw-r--r-- | arch/loongarch/include/asm/qspinlock.h | 41 |
1 files changed, 32 insertions, 9 deletions
diff --git a/arch/loongarch/include/asm/qspinlock.h b/arch/loongarch/include/asm/qspinlock.h index 34f43f8ad591..e76d3aa1e1eb 100644 --- a/arch/loongarch/include/asm/qspinlock.h +++ b/arch/loongarch/include/asm/qspinlock.h @@ -1,18 +1,41 @@ /* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_QSPINLOCK_H -#define _ASM_QSPINLOCK_H +#ifndef _ASM_LOONGARCH_QSPINLOCK_H +#define _ASM_LOONGARCH_QSPINLOCK_H -#include <asm-generic/qspinlock_types.h> +#include <linux/jump_label.h> -#define queued_spin_unlock queued_spin_unlock +#ifdef CONFIG_PARAVIRT -static inline void queued_spin_unlock(struct qspinlock *lock) +DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key); + +#define virt_spin_lock virt_spin_lock + +static inline bool virt_spin_lock(struct qspinlock *lock) { - compiletime_assert_atomic_type(lock->locked); - c_sync(); - WRITE_ONCE(lock->locked, 0); + int val; + + if (!static_branch_unlikely(&virt_spin_lock_key)) + return false; + + /* + * On hypervisors without PARAVIRT_SPINLOCKS support we fall + * back to a Test-and-Set spinlock, because fair locks have + * horrible lock 'holder' preemption issues. + */ + +__retry: + val = atomic_read(&lock->val); + + if (val || !atomic_try_cmpxchg(&lock->val, &val, _Q_LOCKED_VAL)) { + cpu_relax(); + goto __retry; + } + + return true; } +#endif /* CONFIG_PARAVIRT */ + #include <asm-generic/qspinlock.h> -#endif /* _ASM_QSPINLOCK_H */ +#endif // _ASM_LOONGARCH_QSPINLOCK_H |