Explicitly wire the user buffer rather than doing it implicitly in

sbuf_new_for_sysctl(9).  This allows using an sbuf with a SYSCTL_OUT
drain for extremely large amounts of data where the caller knows that
appropriate references are held, and sleeping is not an issue.

Inspired by:	rwatson

1 files changed, 10 insertions, 1 deletions

diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c
index 0143b5b..93fee70 100644
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@@ -125,6 +125,9 @@ sysctl_vm_phys_free(SYSCTL_HANDLER_ARGS)
 	struct vm_freelist *fl;
 	int error, flind, oind, pind;
 
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error != 0)
+		return (error);
 	sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 	for (flind = 0; flind < vm_nfreelists; flind++) {
 		sbuf_printf(&sbuf, "\nFREE LIST %d:\n"
@@ -161,6 +164,9 @@ sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS)
 	struct vm_phys_seg *seg;
 	int error, segind;
 
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error != 0)
+		return (error);
 	sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 	for (segind = 0; segind < vm_phys_nsegs; segind++) {
 		sbuf_printf(&sbuf, "\nSEGMENT %d:\n\n", segind);
@@ -187,8 +193,11 @@ sysctl_vm_phys_lookup_lists(SYSCTL_HANDLER_ARGS)
 	struct sbuf sbuf;
 	int domain, error, flind, ndomains;
 
-	ndomains = vm_nfreelists - VM_NFREELIST + 1;
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error != 0)
+		return (error);
 	sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
+	ndomains = vm_nfreelists - VM_NFREELIST + 1;
 	for (domain = 0; domain < ndomains; domain++) {
 		sbuf_printf(&sbuf, "\nDOMAIN %d:\n\n", domain);
 		for (flind = 0; flind < vm_nfreelists; flind++)