From 1b92846ddd7e1fa8b6e00bead79e839717a05c0a Mon Sep 17 00:00:00 2001
From: mvs <mvs@openbsd.org>
Date: Tue, 20 Aug 2024 13:29:25 +0000
Subject: [PATCH] Unlock KERN_MAXFILES.

`maxfiles' is atomically accessed integer which is lockless and
read-only accessed in file descriptors layer.

lim_startup() called during kernel bootstrap, no need to
atomic_load_int() within.

ok mpi
---
 sys/conf/param.c         |  4 ++--
 sys/kern/kern_descrip.c  | 10 +++++-----
 sys/kern/kern_resource.c |  4 ++--
 sys/kern/kern_sysctl.c   |  3 ++-
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/sys/conf/param.c b/sys/conf/param.c
index 39bf00676d8..cce0eea4f21 100644
--- a/sys/conf/param.c
+++ b/sys/conf/param.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: param.c,v 1.51 2024/08/20 07:48:23 mvs Exp $	*/
+/*	$OpenBSD: param.c,v 1.52 2024/08/20 13:29:25 mvs Exp $	*/
 /*	$NetBSD: param.c,v 1.16 1996/03/12 03:08:40 mrg Exp $	*/
 
 /*
@@ -74,7 +74,7 @@ int	utc_offset = 0;
 int	initialvnodes = NVNODE;
 int	maxprocess = NPROCESS;				/* [a] */
 int	maxthread = 2 * NPROCESS;			/* [a] */
-int	maxfiles = 5 * (NPROCESS + MAXUSERS) + 80;
+int	maxfiles = 5 * (NPROCESS + MAXUSERS) + 80;	/* [a] */
 long	nmbclust = NMBCLUSTERS;
 
 #ifndef BUFCACHEPERCENT
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 84216d168d8..44f2925df88 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_descrip.c,v 1.208 2024/06/22 10:22:29 jsg Exp $	*/
+/*	$OpenBSD: kern_descrip.c,v 1.209 2024/08/20 13:29:25 mvs Exp $	*/
 /*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/
 
 /*
@@ -362,7 +362,7 @@ restart:
 		return (0);
 	}
 	if ((u_int)new >= lim_cur(RLIMIT_NOFILE) ||
-	    (u_int)new >= maxfiles) {
+	    (u_int)new >= atomic_load_int(&maxfiles)) {
 		FRELE(fp, p);
 		return (EBADF);
 	}
@@ -424,7 +424,7 @@ restart:
 	case F_DUPFD_CLOEXEC:
 		newmin = (long)SCARG(uap, arg);
 		if ((u_int)newmin >= lim_cur(RLIMIT_NOFILE) ||
-		    (u_int)newmin >= maxfiles) {
+		    (u_int)newmin >= atomic_load_int(&maxfiles)) {
 			error = EINVAL;
 			break;
 		}
@@ -877,7 +877,7 @@ fdalloc(struct proc *p, int want, int *result)
 	 * expanding the ofile array.
 	 */
 restart:
-	lim = min((int)lim_cur(RLIMIT_NOFILE), maxfiles);
+	lim = min((int)lim_cur(RLIMIT_NOFILE), atomic_load_int(&maxfiles));
 	last = min(fdp->fd_nfiles, lim);
 	if ((i = want) < fdp->fd_freefile)
 		i = fdp->fd_freefile;
@@ -1037,7 +1037,7 @@ fnew(struct proc *p)
 	int nfiles;
 
 	nfiles = atomic_inc_int_nv(&numfiles);
-	if (nfiles > maxfiles) {
+	if (nfiles > atomic_load_int(&maxfiles)) {
 		atomic_dec_int(&numfiles);
 		tablefull("file");
 		return (NULL);
diff --git a/sys/kern/kern_resource.c b/sys/kern/kern_resource.c
index 2afc6287f21..70c2b515034 100644
--- a/sys/kern/kern_resource.c
+++ b/sys/kern/kern_resource.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_resource.c,v 1.87 2024/08/20 07:48:23 mvs Exp $	*/
+/*	$OpenBSD: kern_resource.c,v 1.88 2024/08/20 13:29:25 mvs Exp $	*/
 /*	$NetBSD: kern_resource.c,v 1.38 1996/10/23 07:19:38 matthias Exp $	*/
 
 /*-
@@ -275,7 +275,7 @@ dosetrlimit(struct proc *p, u_int which, struct rlimit *limp)
 		maxlim = maxsmap;
 		break;
 	case RLIMIT_NOFILE:
-		maxlim = maxfiles;
+		maxlim = atomic_load_int(&maxfiles);
 		break;
 	case RLIMIT_NPROC:
 		maxlim = atomic_load_int(&maxprocess);
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index 698548fbcf8..7df7f058385 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.441 2024/08/20 07:48:23 mvs Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.442 2024/08/20 13:29:25 mvs Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -555,6 +555,7 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 	}
 	case KERN_OSREV:
 	case KERN_MAXPROC:
+	case KERN_MAXFILES:
 	case KERN_NFILES:
 	case KERN_TTYCOUNT:
 	case KERN_ARGMAX:
-- 
2.20.1