400 lines
9.8 KiB
C
400 lines
9.8 KiB
C
/*
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* Copyright (2004) Linus Torvalds
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*
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* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
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*
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* Copyright (2004, 2005) Ingo Molnar
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*
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* This file contains the spinlock/rwlock implementations for the
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* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
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*
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* Note that some architectures have special knowledge about the
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* stack frames of these functions in their profile_pc. If you
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* change anything significant here that could change the stack
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* frame contact the architecture maintainers.
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*/
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#include <linux/linkage.h>
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#include <linux/preempt.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/debug_locks.h>
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#include <linux/export.h>
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/*
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* If lockdep is enabled then we use the non-preemption spin-ops
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* even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
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* not re-enabled during lock-acquire (which the preempt-spin-ops do):
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*/
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#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
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/*
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* The __lock_function inlines are taken from
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* include/linux/spinlock_api_smp.h
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*/
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#else
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#define raw_read_can_lock(l) read_can_lock(l)
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#define raw_write_can_lock(l) write_can_lock(l)
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/*
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* Some architectures can relax in favour of the CPU owning the lock.
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*/
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#ifndef arch_read_relax
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# define arch_read_relax(l) cpu_relax()
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#endif
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#ifndef arch_write_relax
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# define arch_write_relax(l) cpu_relax()
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#endif
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#ifndef arch_spin_relax
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# define arch_spin_relax(l) cpu_relax()
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#endif
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/*
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* We build the __lock_function inlines here. They are too large for
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* inlining all over the place, but here is only one user per function
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* which embedds them into the calling _lock_function below.
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*
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* This could be a long-held lock. We both prepare to spin for a long
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* time (making _this_ CPU preemptable if possible), and we also signal
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* towards that other CPU that it should break the lock ASAP.
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*/
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#define BUILD_LOCK_OPS(op, locktype) \
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void __lockfunc __raw_##op##_lock(locktype##_t *lock) \
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{ \
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for (;;) { \
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preempt_disable(); \
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if (likely(do_raw_##op##_trylock(lock))) \
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break; \
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preempt_enable(); \
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\
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if (!(lock)->break_lock) \
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(lock)->break_lock = 1; \
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while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
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arch_##op##_relax(&lock->raw_lock); \
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} \
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(lock)->break_lock = 0; \
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} \
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\
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unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \
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{ \
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unsigned long flags; \
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\
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for (;;) { \
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preempt_disable(); \
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local_irq_save(flags); \
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if (likely(do_raw_##op##_trylock(lock))) \
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break; \
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local_irq_restore(flags); \
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preempt_enable(); \
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\
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if (!(lock)->break_lock) \
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(lock)->break_lock = 1; \
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while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
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arch_##op##_relax(&lock->raw_lock); \
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} \
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(lock)->break_lock = 0; \
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return flags; \
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} \
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\
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void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
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{ \
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_raw_##op##_lock_irqsave(lock); \
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} \
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\
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void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \
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{ \
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unsigned long flags; \
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\
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/* */ \
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/* Careful: we must exclude softirqs too, hence the */ \
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/* irq-disabling. We use the generic preemption-aware */ \
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/* function: */ \
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/**/ \
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flags = _raw_##op##_lock_irqsave(lock); \
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local_bh_disable(); \
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local_irq_restore(flags); \
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} \
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/*
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* Build preemption-friendly versions of the following
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* lock-spinning functions:
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*
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* __[spin|read|write]_lock()
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* __[spin|read|write]_lock_irq()
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* __[spin|read|write]_lock_irqsave()
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* __[spin|read|write]_lock_bh()
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*/
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BUILD_LOCK_OPS(spin, raw_spinlock);
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BUILD_LOCK_OPS(read, rwlock);
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BUILD_LOCK_OPS(write, rwlock);
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#endif
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#ifndef CONFIG_INLINE_SPIN_TRYLOCK
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int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
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{
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return __raw_spin_trylock(lock);
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}
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EXPORT_SYMBOL(_raw_spin_trylock);
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#endif
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#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
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int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
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{
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return __raw_spin_trylock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_spin_trylock_bh);
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#endif
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#ifndef CONFIG_INLINE_SPIN_LOCK
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void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
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{
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__raw_spin_lock(lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock);
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#endif
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#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
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unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
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{
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return __raw_spin_lock_irqsave(lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock_irqsave);
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#endif
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#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
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void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
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{
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__raw_spin_lock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock_irq);
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#endif
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#ifndef CONFIG_INLINE_SPIN_LOCK_BH
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void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
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{
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__raw_spin_lock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock_bh);
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#endif
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#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
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void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
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{
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__raw_spin_unlock(lock);
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}
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EXPORT_SYMBOL(_raw_spin_unlock);
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#endif
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#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
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void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
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{
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__raw_spin_unlock_irqrestore(lock, flags);
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}
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EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
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#endif
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#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
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void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
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{
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__raw_spin_unlock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_spin_unlock_irq);
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#endif
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#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
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void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
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{
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__raw_spin_unlock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_spin_unlock_bh);
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#endif
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#ifndef CONFIG_INLINE_READ_TRYLOCK
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int __lockfunc _raw_read_trylock(rwlock_t *lock)
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{
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return __raw_read_trylock(lock);
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}
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EXPORT_SYMBOL(_raw_read_trylock);
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#endif
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#ifndef CONFIG_INLINE_READ_LOCK
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void __lockfunc _raw_read_lock(rwlock_t *lock)
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{
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__raw_read_lock(lock);
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}
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EXPORT_SYMBOL(_raw_read_lock);
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#endif
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#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
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unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
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{
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return __raw_read_lock_irqsave(lock);
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}
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EXPORT_SYMBOL(_raw_read_lock_irqsave);
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#endif
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#ifndef CONFIG_INLINE_READ_LOCK_IRQ
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void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
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{
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__raw_read_lock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_read_lock_irq);
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#endif
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#ifndef CONFIG_INLINE_READ_LOCK_BH
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void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
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{
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__raw_read_lock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_read_lock_bh);
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#endif
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#ifndef CONFIG_INLINE_READ_UNLOCK
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void __lockfunc _raw_read_unlock(rwlock_t *lock)
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{
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__raw_read_unlock(lock);
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}
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EXPORT_SYMBOL(_raw_read_unlock);
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#endif
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#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
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void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
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{
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__raw_read_unlock_irqrestore(lock, flags);
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}
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EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
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#endif
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#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
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void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
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{
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__raw_read_unlock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_read_unlock_irq);
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#endif
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#ifndef CONFIG_INLINE_READ_UNLOCK_BH
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void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
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{
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__raw_read_unlock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_read_unlock_bh);
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#endif
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#ifndef CONFIG_INLINE_WRITE_TRYLOCK
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int __lockfunc _raw_write_trylock(rwlock_t *lock)
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{
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return __raw_write_trylock(lock);
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}
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EXPORT_SYMBOL(_raw_write_trylock);
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#endif
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#ifndef CONFIG_INLINE_WRITE_LOCK
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void __lockfunc _raw_write_lock(rwlock_t *lock)
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{
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__raw_write_lock(lock);
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}
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EXPORT_SYMBOL(_raw_write_lock);
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#endif
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#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
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unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
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{
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return __raw_write_lock_irqsave(lock);
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}
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EXPORT_SYMBOL(_raw_write_lock_irqsave);
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#endif
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#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
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void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
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{
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__raw_write_lock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_write_lock_irq);
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#endif
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#ifndef CONFIG_INLINE_WRITE_LOCK_BH
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void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
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{
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__raw_write_lock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_write_lock_bh);
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#endif
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#ifndef CONFIG_INLINE_WRITE_UNLOCK
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void __lockfunc _raw_write_unlock(rwlock_t *lock)
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{
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__raw_write_unlock(lock);
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}
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EXPORT_SYMBOL(_raw_write_unlock);
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#endif
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#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
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void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
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{
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__raw_write_unlock_irqrestore(lock, flags);
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}
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EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
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#endif
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#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
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void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
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{
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__raw_write_unlock_irq(lock);
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}
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EXPORT_SYMBOL(_raw_write_unlock_irq);
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#endif
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#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
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void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
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{
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__raw_write_unlock_bh(lock);
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}
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EXPORT_SYMBOL(_raw_write_unlock_bh);
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
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{
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preempt_disable();
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spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
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LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock_nested);
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unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
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int subclass)
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{
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unsigned long flags;
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local_irq_save(flags);
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preempt_disable();
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spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
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LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
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do_raw_spin_lock_flags, &flags);
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return flags;
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}
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EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
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void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
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struct lockdep_map *nest_lock)
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{
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preempt_disable();
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spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
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LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
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}
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EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
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#endif
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notrace int in_lock_functions(unsigned long addr)
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{
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/* Linker adds these: start and end of __lockfunc functions */
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extern char __lock_text_start[], __lock_text_end[];
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return addr >= (unsigned long)__lock_text_start
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&& addr < (unsigned long)__lock_text_end;
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}
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EXPORT_SYMBOL(in_lock_functions);
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