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Index: sys/security/mac/mac_process.c
===================================================================
--- sys/security/mac/mac_process.c
+++ sys/security/mac/mac_process.c
@@ -252,7 +252,7 @@
mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
struct vm_map *map)
{
- vm_map_entry_t vme;
+ vm_map_entry_t prev, vme;
int result;
vm_prot_t revokeperms;
vm_object_t backing_object, object;
@@ -264,7 +264,8 @@
return;
vm_map_lock(map);
- for (vme = map->header.next; vme != &map->header; vme = vme->next) {
+ for (prev = &map->header;
+ (vme = prev->next) != &map->header; prev = vme) {
if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
mac_proc_vm_revoke_recurse(td, cred,
vme->object.sub_map);
@@ -363,7 +364,7 @@
}
pmap_protect(map->pmap, vme->start, vme->end,
vme->protection & ~revokeperms);
- vm_map_simplify_entry(map, vme);
+ vm_map_try_merge_entries(map, prev, vme);
}
}
vm_map_unlock(map);
Index: sys/vm/vm_map.h
===================================================================
--- sys/vm/vm_map.h
+++ sys/vm/vm_map.h
@@ -418,7 +418,8 @@
boolean_t vm_map_lookup_entry (vm_map_t, vm_offset_t, vm_map_entry_t *);
int vm_map_protect (vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t);
int vm_map_remove (vm_map_t, vm_offset_t, vm_offset_t);
-void vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry);
+void vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev,
+ vm_map_entry_t entry);
void vm_map_startup (void);
int vm_map_submap (vm_map_t, vm_offset_t, vm_offset_t, vm_map_t);
int vm_map_sync(vm_map_t, vm_offset_t, vm_offset_t, boolean_t, boolean_t);
Index: sys/vm/vm_map.c
===================================================================
--- sys/vm/vm_map.c
+++ sys/vm/vm_map.c
@@ -1546,7 +1546,7 @@
map->size += end - prev_entry->end;
vm_map_entry_resize(map, prev_entry,
end - prev_entry->end);
- vm_map_simplify_entry(map, prev_entry);
+ vm_map_try_merge_entries(map, prev_entry, prev_entry->next);
return (KERN_SUCCESS);
}
@@ -1606,7 +1606,8 @@
* with the previous entry when object is NULL. Here, we handle the
* other cases, which are less common.
*/
- vm_map_simplify_entry(map, new_entry);
+ vm_map_try_merge_entries(map, prev_entry, new_entry);
+ vm_map_try_merge_entries(map, new_entry, new_entry->next);
if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
@@ -2075,6 +2076,26 @@
}
/*
+ * vm_map_try_merge_entries:
+ *
+ * Compare the given map entry to its predecessor, and merge it into its
+ * predecessor if possible. The entry remains valid, and may be extended.
+ * The predecessor may be deleted.
+ *
+ * The map must be locked.
+ */
+void
+vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev, vm_map_entry_t entry)
+{
+
+ if ((entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 &&
+ vm_map_mergeable_neighbors(prev, entry)) {
+ vm_map_entry_unlink(map, prev, UNLINK_MERGE_NEXT);
+ vm_map_merged_neighbor_dispose(map, prev);
+ }
+}
+
+/*
* vm_map_simplify_entry:
*
* Simplify the given map entry by merging with either neighbor. This
@@ -2086,7 +2107,7 @@
* possibly extended). When merging, this routine may delete one or
* both neighbors.
*/
-void
+static void
vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry)
{
vm_map_entry_t next, prev;
@@ -2176,7 +2197,7 @@
* This routine is called only when it is known that
* the entry must be split.
*/
-static void
+static vm_map_entry_t
_vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
{
vm_map_entry_t new_entry;
@@ -2218,6 +2239,7 @@
* left the same.
*/
}
+ return (new_entry);
}
/*
@@ -2447,7 +2469,7 @@
vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t new_prot, boolean_t set_max)
{
- vm_map_entry_t current, entry, in_tran;
+ vm_map_entry_t current, entry, in_tran, prev;
vm_object_t obj;
struct ucred *cred;
vm_prot_t old_prot;
@@ -2470,8 +2492,8 @@
VM_MAP_RANGE_CHECK(map, start, end);
- if (!vm_map_lookup_entry(map, start, &entry))
- entry = entry->next;
+ vm_map_lookup_entry(map, start - 1, &prev);
+ entry = (prev->end > start) ? prev : prev->next;
/*
* Make a first pass to check for protection violations.
@@ -2513,7 +2535,8 @@
* some may now be mergeable.
*/
rv = KERN_SUCCESS;
- vm_map_clip_start(map, entry, start);
+ if (prev == entry)
+ prev = _vm_map_clip_start(map, entry, start);
for (current = entry; current->start < end; current = current->next) {
vm_map_clip_end(map, current, end);
@@ -2572,7 +2595,8 @@
* [Note that clipping is not necessary the second time.]
*/
for (current = entry; current->start < end;
- vm_map_simplify_entry(map, current), current = current->next) {
+ vm_map_try_merge_entries(map, prev, current),
+ prev = current, current = prev->next) {
if (rv != KERN_SUCCESS ||
(current->eflags & MAP_ENTRY_GUARD) != 0)
continue;
@@ -2610,6 +2634,7 @@
#undef MASK
}
}
+ vm_map_try_merge_entries(map, prev, current);
vm_map_unlock(map);
return (rv);
}
@@ -2629,7 +2654,7 @@
vm_offset_t end,
int behav)
{
- vm_map_entry_t current, entry;
+ vm_map_entry_t current, entry, prev;
bool modify_map;
/*
@@ -2668,12 +2693,8 @@
*/
VM_MAP_RANGE_CHECK(map, start, end);
- if (vm_map_lookup_entry(map, start, &entry)) {
- if (modify_map)
- vm_map_clip_start(map, entry, start);
- } else {
- entry = entry->next;
- }
+ vm_map_lookup_entry(map, start - 1, &prev);
+ entry = (prev->end > start) ? prev : prev->next;
if (modify_map) {
/*
@@ -2682,8 +2703,10 @@
* We clip the vm_map_entry so that behavioral changes are
* limited to the specified address range.
*/
+ if (prev == entry)
+ prev = _vm_map_clip_start(map, entry, start);
for (current = entry; current->start < end;
- current = current->next) {
+ prev = current, current = prev->next) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
@@ -2714,8 +2737,9 @@
default:
break;
}
- vm_map_simplify_entry(map, current);
+ vm_map_try_merge_entries(map, prev, current);
}
+ vm_map_try_merge_entries(map, prev, current);
vm_map_unlock(map);
} else {
vm_pindex_t pstart, pend;

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