/* * 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) * * Note that some architectures have special knowledge about the * stack frames of these functions in their profile_pc. If you * change anything significant here that could change the stack * frame contact the architecture maintainers. */ #include <linux/linkage.h>#include <linux/preempt.h>#include <linux/spinlock.h>#include <linux/interrupt.h>#include <linux/debug_locks.h>#include <linux/export.h> /* * If lockdep is enabled then we use the non-preemption spin-ops * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are * not re-enabled during lock-acquire (which the preempt-spin-ops do): */#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)/* * The __lock_function inlines are taken from * include/linux/spinlock_api_smp.h */#else#define raw_read_can_lock(l)	read_can_lock(l)#define raw_write_can_lock(l)	write_can_lock(l) /* * Some architectures can relax in favour of the CPU owning the lock. */#ifndef arch_read_relax# define arch_read_relax(l)	cpu_relax()#endif#ifndef arch_write_relax# define arch_write_relax(l)	cpu_relax()#endif#ifndef arch_spin_relax# define arch_spin_relax(l)	cpu_relax()#endif /* * We build the __lock_function inlines here. They are too large for * inlining all over the place, but here is only one user per function * which embedds them into the calling _lock_function below. * * 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. */#define BUILD_LOCK_OPS(op, locktype)					\void __lockfunc __raw_##op##_lock(locktype##_t *lock)			\{									\	for (;;) {							\		preempt_disable();					\		if (likely(do_raw_##op##_trylock(lock)))		\			break;						\		preempt_enable();					\									\		if (!(lock)->break_lock)				\			(lock)->break_lock = 1;				\		while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\			arch_##op##_relax(&lock->raw_lock);		\	}								\	(lock)->break_lock = 0;						\}									\									\unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)	\{									\	unsigned long flags;						\									\	for (;;) {							\		preempt_disable();					\		local_irq_save(flags);					\		if (likely(do_raw_##op##_trylock(lock)))		\			break;						\		local_irq_restore(flags);				\		preempt_enable();					\									\		if (!(lock)->break_lock)				\			(lock)->break_lock = 1;				\		while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\			arch_##op##_relax(&lock->raw_lock);		\	}								\	(lock)->break_lock = 0;						\	return flags;							\}									\									\void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)		\{									\	_raw_##op##_lock_irqsave(lock);					\}									\									\void __lockfunc __raw_##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 = _raw_##op##_lock_irqsave(lock);				\	local_bh_disable();						\	local_irq_restore(flags);					\}									\ /* * 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, raw_spinlock);BUILD_LOCK_OPS(read, rwlock);BUILD_LOCK_OPS(write, rwlock); #endif #ifndef CONFIG_INLINE_SPIN_TRYLOCKint __lockfunc _raw_spin_trylock(raw_spinlock_t *lock){	return __raw_spin_trylock(lock);}EXPORT_SYMBOL(_raw_spin_trylock);#endif #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BHint __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock){	return __raw_spin_trylock_bh(lock);}EXPORT_SYMBOL(_raw_spin_trylock_bh);#endif #ifndef CONFIG_INLINE_SPIN_LOCKvoid __lockfunc _raw_spin_lock(raw_spinlock_t *lock){	__raw_spin_lock(lock);}EXPORT_SYMBOL(_raw_spin_lock);#endif #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVEunsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock){	return __raw_spin_lock_irqsave(lock);}EXPORT_SYMBOL(_raw_spin_lock_irqsave);#endif #ifndef CONFIG_INLINE_SPIN_LOCK_IRQvoid __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock){	__raw_spin_lock_irq(lock);}EXPORT_SYMBOL(_raw_spin_lock_irq);#endif #ifndef CONFIG_INLINE_SPIN_LOCK_BHvoid __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock){	__raw_spin_lock_bh(lock);}EXPORT_SYMBOL(_raw_spin_lock_bh);#endif #ifdef CONFIG_UNINLINE_SPIN_UNLOCKvoid __lockfunc _raw_spin_unlock(raw_spinlock_t *lock){	__raw_spin_unlock(lock);}EXPORT_SYMBOL(_raw_spin_unlock);#endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTOREvoid __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags){	__raw_spin_unlock_irqrestore(lock, flags);}EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);#endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQvoid __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock){	__raw_spin_unlock_irq(lock);}EXPORT_SYMBOL(_raw_spin_unlock_irq);#endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_BHvoid __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock){	__raw_spin_unlock_bh(lock);}EXPORT_SYMBOL(_raw_spin_unlock_bh);#endif #ifndef CONFIG_INLINE_READ_TRYLOCKint __lockfunc _raw_read_trylock(rwlock_t *lock){	return __raw_read_trylock(lock);}EXPORT_SYMBOL(_raw_read_trylock);#endif #ifndef CONFIG_INLINE_READ_LOCKvoid __lockfunc _raw_read_lock(rwlock_t *lock){	__raw_read_lock(lock);}EXPORT_SYMBOL(_raw_read_lock);#endif #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVEunsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock){	return __raw_read_lock_irqsave(lock);}EXPORT_SYMBOL(_raw_read_lock_irqsave);#endif #ifndef CONFIG_INLINE_READ_LOCK_IRQvoid __lockfunc _raw_read_lock_irq(rwlock_t *lock){	__raw_read_lock_irq(lock);}EXPORT_SYMBOL(_raw_read_lock_irq);#endif #ifndef CONFIG_INLINE_READ_LOCK_BHvoid __lockfunc _raw_read_lock_bh(rwlock_t *lock){	__raw_read_lock_bh(lock);}EXPORT_SYMBOL(_raw_read_lock_bh);#endif #ifndef CONFIG_INLINE_READ_UNLOCKvoid __lockfunc _raw_read_unlock(rwlock_t *lock){	__raw_read_unlock(lock);}EXPORT_SYMBOL(_raw_read_unlock);#endif #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTOREvoid __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags){	__raw_read_unlock_irqrestore(lock, flags);}EXPORT_SYMBOL(_raw_read_unlock_irqrestore);#endif #ifndef CONFIG_INLINE_READ_UNLOCK_IRQvoid __lockfunc _raw_read_unlock_irq(rwlock_t *lock){	__raw_read_unlock_irq(lock);}EXPORT_SYMBOL(_raw_read_unlock_irq);#endif #ifndef CONFIG_INLINE_READ_UNLOCK_BHvoid __lockfunc _raw_read_unlock_bh(rwlock_t *lock){	__raw_read_unlock_bh(lock);}EXPORT_SYMBOL(_raw_read_unlock_bh);#endif #ifndef CONFIG_INLINE_WRITE_TRYLOCKint __lockfunc _raw_write_trylock(rwlock_t *lock){	return __raw_write_trylock(lock);}EXPORT_SYMBOL(_raw_write_trylock);#endif #ifndef CONFIG_INLINE_WRITE_LOCKvoid __lockfunc _raw_write_lock(rwlock_t *lock){	__raw_write_lock(lock);}EXPORT_SYMBOL(_raw_write_lock);#endif #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVEunsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock){	return __raw_write_lock_irqsave(lock);}EXPORT_SYMBOL(_raw_write_lock_irqsave);#endif #ifndef CONFIG_INLINE_WRITE_LOCK_IRQvoid __lockfunc _raw_write_lock_irq(rwlock_t *lock){	__raw_write_lock_irq(lock);}EXPORT_SYMBOL(_raw_write_lock_irq);#endif #ifndef CONFIG_INLINE_WRITE_LOCK_BHvoid __lockfunc _raw_write_lock_bh(rwlock_t *lock){	__raw_write_lock_bh(lock);}EXPORT_SYMBOL(_raw_write_lock_bh);#endif #ifndef CONFIG_INLINE_WRITE_UNLOCKvoid __lockfunc _raw_write_unlock(rwlock_t *lock){	__raw_write_unlock(lock);}EXPORT_SYMBOL(_raw_write_unlock);#endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTOREvoid __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags){	__raw_write_unlock_irqrestore(lock, flags);}EXPORT_SYMBOL(_raw_write_unlock_irqrestore);#endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQvoid __lockfunc _raw_write_unlock_irq(rwlock_t *lock){	__raw_write_unlock_irq(lock);}EXPORT_SYMBOL(_raw_write_unlock_irq);#endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_BHvoid __lockfunc _raw_write_unlock_bh(rwlock_t *lock){	__raw_write_unlock_bh(lock);}EXPORT_SYMBOL(_raw_write_unlock_bh);#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass){	preempt_disable();	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);	LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);}EXPORT_SYMBOL(_raw_spin_lock_nested); unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,						   int subclass){	unsigned long flags; 	local_irq_save(flags);	preempt_disable();	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);	LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,				do_raw_spin_lock_flags, &flags);	return flags;}EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested); void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,				     struct lockdep_map *nest_lock){	preempt_disable();	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);	LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);}EXPORT_SYMBOL(_raw_spin_lock_nest_lock); #endif notrace 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);