From 96fb8cf258ea2eb6b4a08855f5b214c078c546d6 Mon Sep 17 00:00:00 2001
From: John Dyson <dyson@FreeBSD.org>
Date: Mon, 4 May 1998 17:12:53 +0000
Subject: [PATCH] Fix the shm panic.  I mistakenly used the shadow_count to
 keep the object from being split, and instead added an OBJ_NOSPLIT.

---
 sys/kern/sysv_shm.c | 5 ++---
 sys/vm/vm_map.c     | 6 +++---
 sys/vm/vm_object.h  | 3 ++-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/sys/kern/sysv_shm.c b/sys/kern/sysv_shm.c
index abc1765000f2..25e03a2469f8 100644
--- a/sys/kern/sysv_shm.c
+++ b/sys/kern/sysv_shm.c
@@ -1,4 +1,4 @@
-/*	$Id: sysv_shm.c,v 1.35 1998/03/30 09:50:46 phk Exp $ */
+/*	$Id: sysv_shm.c,v 1.36 1998/05/04 03:01:37 dyson Exp $ */
 /*	$NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $	*/
 
 /*
@@ -145,7 +145,6 @@ shm_deallocate_segment(shmseg)
 	size_t size;
 
 	shm_handle = shmseg->shm_internal;
-	shm_handle->shm_object->shadow_count--;
 	vm_object_deallocate(shm_handle->shm_object);
 	free((caddr_t)shm_handle, M_SHM);
 	shmseg->shm_internal = NULL;
@@ -504,8 +503,8 @@ shmget_allocate_segment(p, uap, mode)
 	shm_handle->shm_object =
 		vm_pager_allocate(OBJT_SWAP, 0, OFF_TO_IDX(size),
 			VM_PROT_DEFAULT, 0);
-	shm_handle->shm_object->shadow_count++;
 	shm_handle->shm_object->flags &= ~OBJ_ONEMAPPING;
+	shm_handle->shm_object->flags |= OBJ_NOSPLIT;
 
 	shmseg->shm_internal = shm_handle;
 	shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index ab961b3e4bf6..aeecbf83f1d3 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_map.c,v 1.123 1998/05/02 06:36:16 dyson Exp $
+ * $Id: vm_map.c,v 1.124 1998/05/04 03:01:44 dyson Exp $
  */
 
 /*
@@ -1832,7 +1832,7 @@ vm_map_delete(map, start, end)
 		} else {
 			pmap_remove(map->pmap, s, e);
 			if (object &&
-				(object->flags & OBJ_ONEMAPPING) &&
+				((object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) &&
 				((object->type == OBJT_SWAP) || (object->type == OBJT_DEFAULT))) {
 				vm_object_collapse(object);
 				vm_object_page_remove(object, offidxstart, offidxend, FALSE);
@@ -2051,7 +2051,7 @@ vm_map_copy_entry(src_map, dst_map, src_entry, dst_entry)
 				(src_object->type == OBJT_DEFAULT ||
 				 src_object->type == OBJT_SWAP)) {
 				vm_object_collapse(src_object);
-				if (src_object->flags & OBJ_ONEMAPPING) {
+				if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) {
 					vm_map_split(src_entry);
 					src_map->timestamp++;
 					src_object = src_entry->object.vm_object;
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index cc9c6bc05f53..e700d5321a69 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_object.h,v 1.47 1998/03/07 21:37:09 dyson Exp $
+ * $Id: vm_object.h,v 1.48 1998/04/29 04:28:12 dyson Exp $
  */
 
 /*
@@ -128,6 +128,7 @@ struct vm_object {
  */
 #define OBJ_ACTIVE	0x0004		/* active objects */
 #define OBJ_DEAD	0x0008		/* dead objects (during rundown) */
+#define	OBJ_NOSPLIT	0x0010		/* dont split this object */
 #define OBJ_PIPWNT	0x0040		/* paging in progress wanted */
 #define	OBJ_WRITEABLE	0x0080		/* object has been made writable */
 #define OBJ_MIGHTBEDIRTY	0x0100	/* object might be dirty */