Make pool_sethardlimit() check that it doesn't decrease the limit below

the current size of the pool. ok art@

4 files changed, 25 insertions, 13 deletions

diff --git a/share/man/man9/pool.9 b/share/man/man9/pool.9
index 02156e4edd6..24785646a11 100644
--- a/share/man/man9/pool.9
+++ b/share/man/man9/pool.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: pool.9,v 1.16 2002/02/25 00:23:20 art Exp $
+.\"	$OpenBSD: pool.9,v 1.17 2002/02/25 04:53:16 dhartmei Exp $
 .\"	$NetBSD: pool.9,v 1.18 2001/06/21 11:59:01 wiz Exp $
 .\"
 .\" Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
 .Fn pool_sethiwat "struct pool *pp" "int n"
 .Ft void
 .Fn pool_setlowat "struct pool *pp" "int n"
-.Ft void
+.Ft int
 .Fo pool_sethardlimit
 .Fa "struct pool *pp"
 .Fa "int n"
@@ -305,8 +305,8 @@ Unlike
 this function does not allocate the necessary memory up-front.
 .El
 .Ss SETTING HARD LIMITS
-The
-.Fn pool_sethardlmit
+The function
+.Fn pool_sethardlimit
 sets a hard limit on the pool to
 .Fa n
 items.
@@ -315,6 +315,9 @@ If the hard limit is reached
 will be printed to the console, but no more than every
 .Fa ratecap
 seconds.
+Upon successful completion, a value of 0 is returned.
+The value EINVAL is returned when the current size of the pool
+already exceeds the requested hard limit.
 .Ss POTENTIAL PITFALLS
 Note that undefined behaviour results when mixing the storage providing
 methods supported by the pool resource routines.
diff --git a/sys/kern/subr_pool.c b/sys/kern/subr_pool.c
index e9ea1657039..d6cb4495ad6 100644
--- a/sys/kern/subr_pool.c
+++ b/sys/kern/subr_pool.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_pool.c,v 1.27 2002/02/23 02:52:56 art Exp $	*/
+/*	$OpenBSD: subr_pool.c,v 1.28 2002/02/25 04:53:16 dhartmei Exp $	*/
 /*	$NetBSD: subr_pool.c,v 1.61 2001/09/26 07:14:56 chs Exp $	*/
 
 /*-
@@ -1217,12 +1217,18 @@ pool_sethiwat(struct pool *pp, int n)
 	simple_unlock(&pp->pr_slock);
 }
 
-void
-pool_sethardlimit(struct pool *pp, int n, const char *warnmess, int ratecap)
+int
+pool_sethardlimit(struct pool *pp, unsigned n, const char *warnmess, int ratecap)
 {
+	int error = 0;
 
 	simple_lock(&pp->pr_slock);
 
+	if (n < pp->pr_nout) {
+		error = EINVAL;
+		goto done;
+	}
+
 	pp->pr_hardlimit = n;
 	pp->pr_hardlimit_warning = warnmess;
 	pp->pr_hardlimit_ratecap.tv_sec = ratecap;
@@ -1233,11 +1239,14 @@ pool_sethardlimit(struct pool *pp, int n, const char *warnmess, int ratecap)
 	 * In-line version of pool_sethiwat(), because we don't want to
 	 * release the lock.
 	 */
-	pp->pr_maxpages = (n == 0)
-		? 0
+	pp->pr_maxpages = (n == 0 || n == UINT_MAX)
+		? n
 		: roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage;
 
+ done:
 	simple_unlock(&pp->pr_slock);
+
+	return (error);
 }
 
 /*
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 6a913bb0e98..8aaddd83194 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_mbuf.c,v 1.55 2002/02/17 22:59:53 maja Exp $	*/
+/*	$OpenBSD: uipc_mbuf.c,v 1.56 2002/02/25 04:53:16 dhartmei Exp $	*/
 /*	$NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $	*/
 
 /*
@@ -130,7 +130,7 @@ mbinit()
 	 * mbuf clusters the kernel is to support.  Log the limit
 	 * reached message max once a minute.
 	 */
-	pool_sethardlimit(&mclpool, nmbclust, mclpool_warnmsg, 60);
+	(void)pool_sethardlimit(&mclpool, nmbclust, mclpool_warnmsg, 60);
 
 	/*
 	 * Set a low water mark for both mbufs and clusters.  This should
diff --git a/sys/sys/pool.h b/sys/sys/pool.h
index 18c25df4cf5..bf1a1a46023 100644
--- a/sys/sys/pool.h
+++ b/sys/sys/pool.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pool.h,v 1.10 2002/02/23 02:52:56 art Exp $	*/
+/*	$OpenBSD: pool.h,v 1.11 2002/02/25 04:53:16 dhartmei Exp $	*/
 /*	$NetBSD: pool.h,v 1.27 2001/06/06 22:00:17 rafal Exp $	*/
 
 /*-
@@ -224,7 +224,7 @@ void		_pool_reclaim(struct pool *, const char *, long);
 int		pool_prime(struct pool *, int);
 void		pool_setlowat(struct pool *, int);
 void		pool_sethiwat(struct pool *, int);
-void		pool_sethardlimit(struct pool *, int, const char *, int);
+int		pool_sethardlimit(struct pool *, unsigned, const char *, int);
 void		pool_drain(void *);
 
 /*