Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

===================================================================
RCS file: /ftp/cvs/cvsroot/src/sys/kern/subr_pool.c,v
retrieving revision 1.21
retrieving revision 1.21.2.4
diff -u -p -r1.21 -r1.21.2.4
--- src/sys/kern/subr_pool.c	1999/03/31 23:23:48	1.21
+++ src/sys/kern/subr_pool.c	1999/06/25 00:08:22	1.21.2.4
@@ -1,4 +1,4 @@
-/*	$NetBSD: subr_pool.c,v 1.21 1999/03/31 23:23:48 thorpej Exp $	*/
+/*	$NetBSD: subr_pool.c,v 1.21.2.4 1999/06/25 00:08:22 perry Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1999 The NetBSD Foundation, Inc.
@@ -73,7 +73,10 @@ static struct pool phpool;
 int pool_inactive_time = 10;
 
 /* Next candidate for drainage (see pool_drain()) */
-static struct pool	*drainpp = NULL;
+static struct pool	*drainpp;
+
+/* This spin lock protects both pool_head and drainpp. */
+struct simplelock pool_head_slock = SIMPLELOCK_INITIALIZER;
 
 struct pool_item_header {
 	/* Page headers */
@@ -254,6 +257,14 @@ pr_rmpage(pp, ph)
 	pp->pr_npages--;
 	pp->pr_npagefree++;
 
+	if ((pp->pr_roflags & PR_PHINPAGE) == 0) {
+		int s;
+		LIST_REMOVE(ph, ph_hashlist);
+		s = splhigh();
+		pool_put(&phpool, ph);
+		splx(s);
+	}
+
 	if (pp->pr_curpage == ph) {
 		/*
 		 * Find a new non-empty page header, if any.
@@ -267,11 +278,6 @@ pr_rmpage(pp, ph)
 
 		pp->pr_curpage = ph;
 	}
-
-	if ((pp->pr_roflags & PR_PHINPAGE) == 0) {
-		LIST_REMOVE(ph, ph_hashlist);
-		pool_put(&phpool, ph);
-	}
 }
 
 /*
@@ -363,7 +369,6 @@ pool_init(pp, size, align, ioff, flags, 
 	/*
 	 * Initialize the pool structure.
 	 */
-	TAILQ_INSERT_TAIL(&pool_head, pp, pr_poollist);
 	TAILQ_INIT(&pp->pr_pagelist);
 	pp->pr_curpage = NULL;
 	pp->pr_npages = 0;
@@ -451,13 +456,17 @@ pool_init(pp, size, align, ioff, flags, 
 
 	/*
 	 * Initialize private page header pool if we haven't done so yet.
+	 * XXX LOCKING.
 	 */
 	if (phpool.pr_size == 0) {
 		pool_init(&phpool, sizeof(struct pool_item_header), 0, 0,
 			  0, "phpool", 0, 0, 0, 0);
 	}
 
-	return;
+	/* Insert into the list of all pools. */
+	simple_lock(&pool_head_slock);
+	TAILQ_INSERT_TAIL(&pool_head, pp, pr_poollist);
+	simple_unlock(&pool_head_slock);
 }
 
 /*
@@ -483,8 +492,11 @@ pool_destroy(pp)
 			pr_rmpage(pp, ph);
 
 	/* Remove from global pool list */
+	simple_lock(&pool_head_slock);
 	TAILQ_REMOVE(&pool_head, pp, pr_poollist);
+	/* XXX Only clear this if we were drainpp? */
 	drainpp = NULL;
+	simple_unlock(&pool_head_slock);
 
 #ifdef POOL_DIAGNOSTIC
 	if ((pp->pr_roflags & PR_LOGGING) != 0)
@@ -924,12 +936,14 @@ pool_prime_page(pp, storage)
 	caddr_t cp = storage;
 	unsigned int align = pp->pr_align;
 	unsigned int ioff = pp->pr_itemoffset;
-	int n;
+	int s, n;
 
 	if ((pp->pr_roflags & PR_PHINPAGE) != 0) {
 		ph = (struct pool_item_header *)(cp + pp->pr_phoffset);
 	} else {
+		s = splhigh();
 		ph = pool_get(&phpool, PR_URGENT);
+		splx(s);
 		LIST_INSERT_HEAD(&pp->pr_hashtab[PR_HASH_INDEX(pp, cp)],
 				 ph, ph_hashlist);
 	}
@@ -1215,19 +1229,21 @@ pool_drain(arg)
 	void *arg;
 {
 	struct pool *pp;
-	int s = splimp();
+	int s;
 
-	/* XXX:lock pool head */
-	if (drainpp == NULL && (drainpp = TAILQ_FIRST(&pool_head)) == NULL) {
-		splx(s);
-		return;
-	}
+	s = splimp();
+	simple_lock(&pool_head_slock);
+
+	if (drainpp == NULL && (drainpp = TAILQ_FIRST(&pool_head)) == NULL)
+		goto out;
 
 	pp = drainpp;
 	drainpp = TAILQ_NEXT(pp, pr_poollist);
-	/* XXX:unlock pool head */
 
 	pool_reclaim(pp);
+
+ out:
+	simple_unlock(&pool_head_slock);
 	splx(s);
 }