Kill the horrible hack of storing the pid in struct selinfo.

Instead, keep the proc pointer in it and put the selinfo on a list
in struct proc in selrecord. Then clean up the list when leaving
sys_select and sys_poll.

miod@ ok, testing by many, including Bobs spamd boxes.

1 files changed, 36 insertions, 20 deletions

diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 31cbafefff7..a79c121c00c 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_generic.c,v 1.55 2007/03/15 10:22:30 art Exp $	*/
+/*	$OpenBSD: sys_generic.c,v 1.56 2007/03/24 16:01:22 art Exp $	*/
 /*	$NetBSD: sys_generic.c,v 1.24 1996/03/29 00:25:32 cgd Exp $	*/
 
 /*
@@ -66,6 +66,8 @@ int selscan(struct proc *, fd_set *, fd_set *, int, int, register_t *);
 int seltrue(dev_t, int, struct proc *);
 void pollscan(struct proc *, struct pollfd *, u_int, register_t *);
 
+void sel_clean_proclist(struct proc *);
+
 /*
  * Read system call.
  */
@@ -708,6 +710,7 @@ retry:
 	if (error == 0)
 		goto retry;
 done:
+	sel_clean_proclist(p);
 	atomic_clearbits_int(&p->p_flag, P_SELECT);
 	/* select is not restarted after signals... */
 	if (error == ERESTART)
@@ -781,17 +784,12 @@ seltrue(dev_t dev, int events, struct proc *p)
 void
 selrecord(struct proc *selector, struct selinfo *sip)
 {
-	struct proc *p;
-	pid_t mypid;
-
-	mypid = selector->p_pid;
-	if (sip->si_selpid == mypid)
-		return;
-	if (sip->si_selpid && (p = pfind(sip->si_selpid)) &&
-	    p->p_wchan == (caddr_t)&selwait)
+	if (sip->si_selproc == NULL) {
+		sip->si_selproc = selector;
+		TAILQ_INSERT_TAIL(&selector->p_selects, sip, si_list);
+	} else if (sip->si_selproc != selector) {
 		sip->si_flags |= SI_COLL;
-	else
-		sip->si_selpid = mypid;
+	}
 }
 
 /*
@@ -803,25 +801,42 @@ selwakeup(struct selinfo *sip)
 	struct proc *p;
 	int s;
 
-	if (sip->si_selpid == 0)
-		return;
 	if (sip->si_flags & SI_COLL) {
 		nselcoll++;
 		sip->si_flags &= ~SI_COLL;
 		wakeup(&selwait);
 	}
-	p = pfind(sip->si_selpid);
-	sip->si_selpid = 0;
-	if (p != NULL) {
-		SCHED_LOCK(s);
-		if (p->p_wchan == (caddr_t)&selwait) {
+
+	/*
+	 * We check the process once before locking.
+	 * Then we wake the process and clean up its
+	 * selects list.
+	 */
+	if (sip->si_selproc == NULL)
+		return;
+
+	SCHED_LOCK(s);
+	if ((p = sip->si_selproc) != NULL) {
+		if (p->p_wchan != NULL) {
 			if (p->p_stat == SSLEEP)
 				setrunnable(p);
 			else
 				unsleep(p);
-		} else if (p->p_flag & P_SELECT)
+		} else {
 			atomic_clearbits_int(&p->p_flag, P_SELECT);
-		SCHED_UNLOCK(s);
+		}
+	}
+	SCHED_UNLOCK(s);
+}
+
+void
+sel_clean_proclist(struct proc *p)
+{
+	struct selinfo *sip;
+
+	while ((sip = TAILQ_FIRST(&p->p_selects)) != NULL) {
+		sip->si_selproc = NULL;
+		TAILQ_REMOVE(&p->p_selects, sip, si_list);
 	}
 }
 
@@ -932,6 +947,7 @@ retry:
 		goto retry;
 
 done:
+	sel_clean_proclist(p);
 	atomic_clearbits_int(&p->p_flag, P_SELECT);
 	/*
 	 * NOTE: poll(2) is not restarted after a signal and EWOULDBLOCK is