plan 9 kernel history: overview | file list | diff list

1993/0501/port/taslock.c (diff list | history)

port/taslock.c on 1992/0222
1992/0222    
#include "u.h" 
1992/0321    
#include "../port/lib.h" 
1992/0222    
#include "mem.h" 
#include "dat.h" 
#include "fns.h" 
#include "../port/error.h" 
 
void 
lock(Lock *l) 
{ 
	int i; 
	ulong pc; 
 
	pc = getcallerpc(((uchar*)&l) - sizeof(l)); 
1992/0914    
 
	for(i = 0; i < 10000000; i++){ 
    		if (tas(&l->key) == 0){ 
			l->pc = pc; 
1992/0222    
			return; 
		} 
	} 
	l->key = 0; 
1992/0914    
	panic("lock loop 0x%lux key 0x%lux pc 0x%lux held by pc 0x%lux\n", 
			l->key, i, pc, l->pc); 
1992/0222    
} 
 
int 
canlock(Lock *l) 
{ 
	if(tas(&l->key)) 
		return 0; 
	l->pc = getcallerpc(((uchar*)&l) - sizeof(l)); 
	return 1; 
} 
 
void 
unlock(Lock *l) 
{ 
	l->pc = 0; 
	l->key = 0; 
} 


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comments to russ cox (rsc@swtch.com)