Date: Fri, 20 Jul 2001 09:00:00 -0700 From: Julian Elischer <julian@elischer.org> To: current@freebsd.org Subject: Re: huh? in Selrecord(): what is this for? Message-ID: <3B585580.6A697127@elischer.org> References: <3B5854E3.B6D9C86D@elischer.org>
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Never mind.. I'm an ijut...
Julian Elischer wrote:
>
> void
> selrecord(selector, sip)
> struct proc *selector;
> struct selinfo *sip;
> {
> struct proc *p;
> pid_t mypid;
>
> mypid = selector->p_pid;
> if (sip->si_pid == mypid)
> return;
> if (sip->si_pid && (p = pfind(sip->si_pid))) {
>
> Why do we look up 'p' when we got it as an argument?
> (race condition detection?)
>
> (I'm modifying things for threads so I came up against this....)
>
> mtx_lock_spin(&sched_lock);
> if (p->p_wchan == (caddr_t)&selwait) {
> mtx_unlock_spin(&sched_lock);
> PROC_UNLOCK(p);
> sip->si_flags |= SI_COLL;
> return;
> }
> mtx_unlock_spin(&sched_lock);
> PROC_UNLOCK(p);
> }
> sip->si_pid = mypid;
> }
> --
> +------------------------------------+ ______ _ __
> | __--_|\ Julian Elischer | \ U \/ / hard at work in
> | / \ julian@elischer.org +------>x USA \ a very strange
> | ( OZ ) \___ ___ | country !
> +- X_.---._/ presently in San Francisco \_/ \\
> v
--
+------------------------------------+ ______ _ __
| __--_|\ Julian Elischer | \ U \/ / hard at work in
| / \ julian@elischer.org +------>x USA \ a very strange
| ( OZ ) \___ ___ | country !
+- X_.---._/ presently in San Francisco \_/ \\
v
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