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Extract code common to _vm_map_clip_start and _vm_map_clip_end into a

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function, vm_map_entry_clone, that can be invoked by each.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D22760
This commit is contained in:
Doug Moore 2019-12-11 16:09:57 +00:00
parent 64ebbdd54d
commit 037c0994bf
1 changed files with 38 additions and 41 deletions
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79
sys/vm/vm_map.c
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@ -2290,6 +2290,42 @@ vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry)
}
}
/*
* vm_map_entry_clone
*
* Create a duplicate map entry for clipping.
*/
static vm_map_entry_t
vm_map_entry_clone(vm_map_t map, vm_map_entry_t entry)
{
vm_map_entry_t new_entry;
VM_MAP_ASSERT_LOCKED(map);
/*
* Create a backing object now, if none exists, so that more individual
* objects won't be created after the map entry is split.
*/
vm_map_entry_charge_object(map, entry);
/* Clone the entry. */
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
if (new_entry->cred != NULL)
crhold(entry->cred);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
vm_map_entry_set_vnode_text(new_entry, true);
/*
* The object->un_pager.vnp.writemappings for the object of
* MAP_ENTRY_WRITECNT type entry shall be kept as is here. The
* virtual pages are re-distributed among the clipped entries,
* so the sum is left the same.
*/
}
return (new_entry);
}
/*
* vm_map_clip_start: [ internal use only ]
*
@ -2316,15 +2352,7 @@ _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
KASSERT(entry->end > start && entry->start < start,
("_vm_map_clip_start: invalid clip of entry %p", entry));
/*
* Create a backing object now, if none exists, so that more individual
* objects won't be created after the map entry is split.
*/
vm_map_entry_charge_object(map, entry);
/* Clone the entry. */
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry = vm_map_entry_clone(map, entry);
/*
* Split off the front portion. Insert the new entry BEFORE this one,
@ -2333,22 +2361,7 @@ _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
new_entry->end = start;
entry->offset += (start - entry->start);
entry->start = start;
if (new_entry->cred != NULL)
crhold(entry->cred);
vm_map_entry_link(map, new_entry);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
vm_map_entry_set_vnode_text(new_entry, true);
/*
* The object->un_pager.vnp.writemappings for the
* object of MAP_ENTRY_WRITECNT type entry shall be
* kept as is here. The virtual pages are
* re-distributed among the clipped entries, so the sum is
* left the same.
*/
}
}
/*
@ -2377,15 +2390,7 @@ _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end)
KASSERT(entry->start < end && entry->end > end,
("_vm_map_clip_end: invalid clip of entry %p", entry));
/*
* Create a backing object now, if none exists, so that more individual
* objects won't be created after the map entry is split.
*/
vm_map_entry_charge_object(map, entry);
/* Clone the entry. */
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry = vm_map_entry_clone(map, entry);
/*
* Split off the back portion. Insert the new entry AFTER this one,
@ -2393,15 +2398,7 @@ _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end)
*/
new_entry->start = entry->end = end;
new_entry->offset += (end - entry->start);
if (new_entry->cred != NULL)
crhold(entry->cred);
vm_map_entry_link(map, new_entry);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
vm_map_entry_set_vnode_text(new_entry, true);
}
}
/*