Function vm_map_unwire

freebsd/vm/vm_map.c:3253–3386

* vm_map_unwire: * * Implements both kernel and user unwiring. */

 *	Implements both kernel and user unwiring.
 */
int
vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
    int flags)
{
	vm_map_entry_t entry, first_entry, next_entry, prev_entry;
	int rv;
	bool holes_ok, need_wakeup, user_unwire;

	if (start == end)
		return (KERN_SUCCESS);
	holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0;
	user_unwire = (flags & VM_MAP_WIRE_USER) != 0;
	vm_map_lock(map);
	VM_MAP_RANGE_CHECK(map, start, end);
	if (!vm_map_lookup_entry(map, start, &first_entry)) {
		if (holes_ok)
			first_entry = vm_map_entry_succ(first_entry);
		else {
			vm_map_unlock(map);
			return (KERN_INVALID_ADDRESS);
		}
	}
	rv = KERN_SUCCESS;
	for (entry = first_entry; entry->start < end; entry = next_entry) {
		if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
			/*
			 * We have not yet clipped the entry.
			 */
			next_entry = vm_map_entry_in_transition(map, start,
			    &end, holes_ok, entry);
			if (next_entry == NULL) {
				if (entry == first_entry) {
					vm_map_unlock(map);
					return (KERN_INVALID_ADDRESS);
				}
				rv = KERN_INVALID_ADDRESS;
				break;
			}
			first_entry = (entry == first_entry) ?
			    next_entry : NULL;
			continue;
		}
		rv = vm_map_clip_start(map, entry, start);
		if (rv != KERN_SUCCESS)
			break;
		rv = vm_map_clip_end(map, entry, end);
		if (rv != KERN_SUCCESS)
			break;

		/*
		 * Mark the entry in case the map lock is released.  (See
		 * above.)
		 */
		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 &&
		    entry->wiring_thread == NULL,
		    ("owned map entry %p", entry));
		entry->eflags |= MAP_ENTRY_IN_TRANSITION;
		entry->wiring_thread = curthread;