/* * Copyright (2004) Linus Torvalds * * Author: Zwane Mwaikambo <zwane@fsmlabs.com> * * Copyright (2004, 2005) Ingo Molnar * * This file contains the spinlock/rwlock implementations for the * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them) */ #include <linux/config.h>#include <linux/linkage.h>#include <linux/preempt.h>#include <linux/spinlock.h>#include <linux/interrupt.h>#include <linux/module.h> /* * Generic declaration of the raw read_trylock() function, * architectures are supposed to optimize this: */int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock){	__raw_read_lock(lock);	return 1;}EXPORT_SYMBOL(generic__raw_read_trylock); int __lockfunc _spin_trylock(spinlock_t *lock){	preempt_disable();	if (_raw_spin_trylock(lock))		return 1;		preempt_enable();	return 0;}EXPORT_SYMBOL(_spin_trylock); int __lockfunc _read_trylock(rwlock_t *lock){	preempt_disable();	if (_raw_read_trylock(lock))		return 1; 	preempt_enable();	return 0;}EXPORT_SYMBOL(_read_trylock); int __lockfunc _write_trylock(rwlock_t *lock){	preempt_disable();	if (_raw_write_trylock(lock))		return 1; 	preempt_enable();	return 0;}EXPORT_SYMBOL(_write_trylock); #if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) void __lockfunc _read_lock(rwlock_t *lock){	preempt_disable();	_raw_read_lock(lock);}EXPORT_SYMBOL(_read_lock); unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock){	unsigned long flags; 	local_irq_save(flags);	preempt_disable();	_raw_spin_lock_flags(lock, &flags);	return flags;}EXPORT_SYMBOL(_spin_lock_irqsave); void __lockfunc _spin_lock_irq(spinlock_t *lock){	local_irq_disable();	preempt_disable();	_raw_spin_lock(lock);}EXPORT_SYMBOL(_spin_lock_irq); void __lockfunc _spin_lock_bh(spinlock_t *lock){	local_bh_disable();	preempt_disable();	_raw_spin_lock(lock);}EXPORT_SYMBOL(_spin_lock_bh); unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock){	unsigned long flags; 	local_irq_save(flags);	preempt_disable();	_raw_read_lock(lock);	return flags;}EXPORT_SYMBOL(_read_lock_irqsave); void __lockfunc _read_lock_irq(rwlock_t *lock){	local_irq_disable();	preempt_disable();	_raw_read_lock(lock);}EXPORT_SYMBOL(_read_lock_irq); void __lockfunc _read_lock_bh(rwlock_t *lock){	local_bh_disable();	preempt_disable();	_raw_read_lock(lock);}EXPORT_SYMBOL(_read_lock_bh); unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock){	unsigned long flags; 	local_irq_save(flags);	preempt_disable();	_raw_write_lock(lock);	return flags;}EXPORT_SYMBOL(_write_lock_irqsave); void __lockfunc _write_lock_irq(rwlock_t *lock){	local_irq_disable();	preempt_disable();	_raw_write_lock(lock);}EXPORT_SYMBOL(_write_lock_irq); void __lockfunc _write_lock_bh(rwlock_t *lock){	local_bh_disable();	preempt_disable();	_raw_write_lock(lock);}EXPORT_SYMBOL(_write_lock_bh); void __lockfunc _spin_lock(spinlock_t *lock){	preempt_disable();	_raw_spin_lock(lock);} EXPORT_SYMBOL(_spin_lock); void __lockfunc _write_lock(rwlock_t *lock){	preempt_disable();	_raw_write_lock(lock);} EXPORT_SYMBOL(_write_lock); #else /* CONFIG_PREEMPT: */ /* * This could be a long-held lock. We both prepare to spin for a long * time (making _this_ CPU preemptable if possible), and we also signal * towards that other CPU that it should break the lock ASAP. * * (We do this in a function because inlining it would be excessive.) */ #define BUILD_LOCK_OPS(op, locktype)					\void __lockfunc _##op##_lock(locktype##_t *lock)			\{									\	for (;;) {							\		preempt_disable();					\		if (likely(_raw_##op##_trylock(lock)))			\			break;						\		preempt_enable();					\									\		if (!(lock)->break_lock)				\			(lock)->break_lock = 1;				\		while (!op##_can_lock(lock) && (lock)->break_lock)	\			cpu_relax();					\	}								\	(lock)->break_lock = 0;						\}									\									\EXPORT_SYMBOL(_##op##_lock);						\									\unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock)	\{									\	unsigned long flags;						\									\	for (;;) {							\		preempt_disable();					\		local_irq_save(flags);					\		if (likely(_raw_##op##_trylock(lock)))			\			break;						\		local_irq_restore(flags);				\		preempt_enable();					\									\		if (!(lock)->break_lock)				\			(lock)->break_lock = 1;				\		while (!op##_can_lock(lock) && (lock)->break_lock)	\			cpu_relax();					\	}								\	(lock)->break_lock = 0;						\	return flags;							\}									\									\EXPORT_SYMBOL(_##op##_lock_irqsave);					\									\void __lockfunc _##op##_lock_irq(locktype##_t *lock)			\{									\	_##op##_lock_irqsave(lock);					\}									\									\EXPORT_SYMBOL(_##op##_lock_irq);					\									\void __lockfunc _##op##_lock_bh(locktype##_t *lock)			\{									\	unsigned long flags;						\									\	/*							*/	\	/* Careful: we must exclude softirqs too, hence the	*/	\	/* irq-disabling. We use the generic preemption-aware	*/	\	/* function:						*/	\	/**/								\	flags = _##op##_lock_irqsave(lock);				\	local_bh_disable();						\	local_irq_restore(flags);					\}									\									\EXPORT_SYMBOL(_##op##_lock_bh) /* * Build preemption-friendly versions of the following * lock-spinning functions: * *         _[spin|read|write]_lock() *         _[spin|read|write]_lock_irq() *         _[spin|read|write]_lock_irqsave() *         _[spin|read|write]_lock_bh() */BUILD_LOCK_OPS(spin, spinlock);BUILD_LOCK_OPS(read, rwlock);BUILD_LOCK_OPS(write, rwlock); #endif /* CONFIG_PREEMPT */ void __lockfunc _spin_unlock(spinlock_t *lock){	_raw_spin_unlock(lock);	preempt_enable();}EXPORT_SYMBOL(_spin_unlock); void __lockfunc _write_unlock(rwlock_t *lock){	_raw_write_unlock(lock);	preempt_enable();}EXPORT_SYMBOL(_write_unlock); void __lockfunc _read_unlock(rwlock_t *lock){	_raw_read_unlock(lock);	preempt_enable();}EXPORT_SYMBOL(_read_unlock); void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags){	_raw_spin_unlock(lock);	local_irq_restore(flags);	preempt_enable();}EXPORT_SYMBOL(_spin_unlock_irqrestore); void __lockfunc _spin_unlock_irq(spinlock_t *lock){	_raw_spin_unlock(lock);	local_irq_enable();	preempt_enable();}EXPORT_SYMBOL(_spin_unlock_irq); void __lockfunc _spin_unlock_bh(spinlock_t *lock){	_raw_spin_unlock(lock);	preempt_enable_no_resched();	local_bh_enable();}EXPORT_SYMBOL(_spin_unlock_bh); void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags){	_raw_read_unlock(lock);	local_irq_restore(flags);	preempt_enable();}EXPORT_SYMBOL(_read_unlock_irqrestore); void __lockfunc _read_unlock_irq(rwlock_t *lock){	_raw_read_unlock(lock);	local_irq_enable();	preempt_enable();}EXPORT_SYMBOL(_read_unlock_irq); void __lockfunc _read_unlock_bh(rwlock_t *lock){	_raw_read_unlock(lock);	preempt_enable_no_resched();	local_bh_enable();}EXPORT_SYMBOL(_read_unlock_bh); void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags){	_raw_write_unlock(lock);	local_irq_restore(flags);	preempt_enable();}EXPORT_SYMBOL(_write_unlock_irqrestore); void __lockfunc _write_unlock_irq(rwlock_t *lock){	_raw_write_unlock(lock);	local_irq_enable();	preempt_enable();}EXPORT_SYMBOL(_write_unlock_irq); void __lockfunc _write_unlock_bh(rwlock_t *lock){	_raw_write_unlock(lock);	preempt_enable_no_resched();	local_bh_enable();}EXPORT_SYMBOL(_write_unlock_bh); int __lockfunc _spin_trylock_bh(spinlock_t *lock){	local_bh_disable();	preempt_disable();	if (_raw_spin_trylock(lock))		return 1; 	preempt_enable_no_resched();	local_bh_enable();	return 0;}EXPORT_SYMBOL(_spin_trylock_bh); int in_lock_functions(unsigned long addr){	/* Linker adds these: start and end of __lockfunc functions */	extern char __lock_text_start[], __lock_text_end[]; 	return addr >= (unsigned long)__lock_text_start	&& addr < (unsigned long)__lock_text_end;}EXPORT_SYMBOL(in_lock_functions);