1991/0727/port/qlock.c (diff list | history)

port/qlock.c on 1991/0428
1991/0428		#include "u.h" #include "lib.h" #include "mem.h" #include "dat.h" #include "fns.h" void qlock(QLock *q) { Proc *p;
1991/0705		if(canlock(&q->use))
1991/0428		return; lock(&q->queue); if(canlock(&q->use)){ unlock(&q->queue); return; }
1991/0711		if(u == 0) panic("qlock");
1991/0428		p = q->tail; if(p == 0) q->head = u->p; else p->qnext = u->p; q->tail = u->p; u->p->qnext = 0; u->p->state = Queueing; /* u->p->qlock = q; /* DEBUG */ unlock(&q->queue); sched(); } int canqlock(QLock *q) { return canlock(&q->use); } void qunlock(QLock *q) { Proc *p; lock(&q->queue); /* u->p->qlock = 0; /* DEBUG */ if(q->head){ p = q->head; q->head = p->qnext; if(q->head == 0) q->tail = 0; unlock(&q->queue); ready(p); }else{ unlock(&q->use); unlock(&q->queue); } }