From 2c8c434fa446d03382c8981b8039da8809759625 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sun, 17 Jan 2010 13:32:18 -0800
Subject: [PATCH] kernel - do not wire user pages in sysctl

* sysctl processes have not assumed that user pages would be wired
  for a long time.

* This also prevents sysctl from causing VM faults on the user memory
  after returning due to wiring changes.

  For example 'vmstat 1' no longer produces faults in the flt column
  generated by vmstat itself on every iteration.
---
 sys/kern/kern_sysctl.c | 12 ++++++++++--
 sys/sys/sysctl.h       |  3 +--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index cd118d6ca0..24bf124abf 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1017,14 +1017,18 @@ kernel_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, void *new, s
 
 	req.oldfunc = sysctl_old_kernel;
 	req.newfunc = sysctl_new_kernel;
+#if 0
 	req.lock = 1;
+#endif
 
 	sysctl_lock(LK_SHARED);
 
 	error = sysctl_root(0, name, namelen, &req);
 
+#if 0
 	if (req.lock == 2)
 		vsunlock(req.oldptr, req.oldlen);
+#endif
 
 	sysctl_unlock();
 
@@ -1071,10 +1075,12 @@ sysctl_old_user(struct sysctl_req *req, const void *p, size_t l)
 	int error = 0;
 	size_t i = 0;
 
+#if 0
 	if (req->lock == 1 && req->oldptr) {
 		vslock(req->oldptr, req->oldlen);
 		req->lock = 2;
 	}
+#endif
 	if (req->oldptr) {
 		i = l;
 		if (i > req->oldlen - req->oldidx)
@@ -1118,8 +1124,6 @@ sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
 	while (oid && indx < CTL_MAXNAME) {
 		if (oid->oid_number == name[indx]) {
 			indx++;
-			if (oid->oid_kind & CTLFLAG_NOLOCK)
-				req->lock = 0;
 			if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
 				if (oid->oid_handler != NULL ||
 				    indx == namelen) {
@@ -1268,7 +1272,9 @@ userland_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, int inkern
 
 	req.oldfunc = sysctl_old_user;
 	req.newfunc = sysctl_new_user;
+#if 0
 	req.lock = 1;
+#endif
 	req.td = curthread;
 
 	sysctl_lock(LK_SHARED);
@@ -1279,8 +1285,10 @@ userland_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, int inkern
 	} while (error == EAGAIN);
 
 	req = req2;
+#if 0
 	if (req.lock == 2)
 		vsunlock(req.oldptr, req.oldlen);
+#endif
 
 	sysctl_unlock();
 
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index f8023fb146..f6646b142a 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -89,7 +89,6 @@ struct ctlname {
 #define CTLFLAG_RD	0x80000000	/* Allow reads of variable */
 #define CTLFLAG_WR	0x40000000	/* Allow writes to the variable */
 #define CTLFLAG_RW	(CTLFLAG_RD|CTLFLAG_WR)
-#define CTLFLAG_NOLOCK	0x20000000	/* XXX Don't Lock */
 #define CTLFLAG_ANYBODY	0x10000000	/* All users can set this var */
 #define CTLFLAG_SECURE	0x08000000	/* Permit set only if securelevel<=0 */
 #define CTLFLAG_PRISON	0x04000000	/* Prisoned roots can fiddle */
@@ -117,7 +116,7 @@ struct ctlname {
  */
 struct sysctl_req {
 	struct thread	*td;
-	int		lock;
+	int		unused01;	/* was lock */
 	void		*oldptr;
 	size_t		oldlen;
 	size_t		oldidx;
-- 
2.11.4.GIT