/* *	SMP locks primitives for building ix86 locks *	(not yet used). * *		Alan Cox, alan@redhat.com, 1995 */ /* *	This would be much easier but far less clear and easy *	to borrow for other processors if it was just assembler. */extern __inline__ void prim_spin_lock(struct spinlock *sp){	int processor=smp_processor_id();		/*	 *	Grab the lock bit	 */	 	while(lock_set_bit(0,&sp->lock))	{		/*		 *	Failed, but that's cos we own it!		 */		 		if(sp->cpu==processor)		{			sp->users++;			return 0;		}		/*		 *	Spin in the cache S state if possible		 */		while(sp->lock)		{			/*			 *	Wait for any invalidates to go off			 */			 			if(smp_invalidate_needed&(1<<processor))				while(lock_clear_bit(processor,&smp_invalidate_needed))					local_flush_tlb();			sp->spins++;		}		/*		 *	Someone wrote the line, we go 'I' and get		 *	the cache entry. Now try to regrab		 */	}	sp->users++;sp->cpu=processor;	return 1;}/* *	Release a spin lock */ extern __inline__ int prim_spin_unlock(struct spinlock *sp){	/* This is safe. The decrement is still guarded by the lock. A multilock would	   not be safe this way */	if(!--sp->users)	{		sp->cpu= NO_PROC_ID;lock_clear_bit(0,&sp->lock);		return 1;	}	return 0;}/* *	Non blocking lock grab */ extern __inline__ int prim_spin_lock_nb(struct spinlock *sp){	if(lock_set_bit(0,&sp->lock))		return 0;		/* Locked already */	sp->users++;	return 1;			/* We got the lock */}/* *	These wrap the locking primitives up for usage */ extern __inline__ void spinlock(struct spinlock *sp){	if(sp->priority<current->lock_order)		panic("lock order violation: %s (%d)\n", sp->name, current->lock_order);	if(prim_spin_lock(sp))	{		/*		 *	We got a new lock. Update the priority chain		 */		sp->oldpri=current->lock_order;		current->lock_order=sp->priority;	}}extern __inline__ void spinunlock(struct spinlock *sp){	int pri;	if(current->lock_order!=sp->priority)		panic("lock release order violation %s (%d)\n", sp->name, current->lock_order);	pri=sp->oldpri;	if(prim_spin_unlock(sp))	{		/*		 *	Update the debugging lock priority chain. We dumped		 *	our last right to the lock.		 */		current->lock_order=sp->pri;	}	}extern __inline__ void spintestlock(struct spinlock *sp){	/*	 *	We do no sanity checks, it's legal to optimistically	 *	get a lower lock.	 */	prim_spin_lock_nb(sp);}extern __inline__ void spintestunlock(struct spinlock *sp){	/*	 *	A testlock doesn't update the lock chain so we	 *	must not update it on free	 */	prim_spin_unlock(sp);}