Subversion Repositories planix.SVN

#include        "u.h"
#include        "lib.h"
#include        "dat.h"
#include        "fns.h"
#include        "error.h"

void
sleep(Rendez *r, int (*f)(void*), void *arg)
{
        int s;

        s = splhi();

        lock(&r->lk);
        lock(&up->rlock);
        if(r->p){
                print("double sleep %lud %lud\n", r->p->pid, up->pid);
                dumpstack();
        }

        /*
         *  Wakeup only knows there may be something to do by testing
         *  r->p in order to get something to lock on.
         *  Flush that information out to memory in case the sleep is
         *  committed.
         */
        r->p = up;

        if((*f)(arg) || up->notepending){
                /*
                 *  if condition happened or a note is pending
                 *  never mind
                 */
                r->p = nil;
                unlock(&up->rlock);
                unlock(&r->lk);
        } else {
                /*
                 *  now we are committed to
                 *  change state and call scheduler
                 */
                up->state = Wakeme;
                up->r = r;

                /* statistics */
                /* m->cs++; */

                unlock(&up->rlock);
                unlock(&r->lk);

                procsleep();
        }

        if(up->notepending) {
                up->notepending = 0;
                splx(s);
                error(Eintr);
        }

        splx(s);
}

Proc*
wakeup(Rendez *r)
{
        Proc *p;
        int s;

        s = splhi();

        lock(&r->lk);
        p = r->p;

        if(p != nil){
                lock(&p->rlock);
                if(p->state != Wakeme || p->r != r)
                        panic("wakeup: state");
                r->p = nil;
                p->r = nil;
                p->state = Running;
                procwakeup(p);
                unlock(&p->rlock);
        }
        unlock(&r->lk);

        splx(s);

        return p;
}