Function vm_map_clip_end

freebsd/vm/vm_map.c:2537–2572

* vm_map_clip_end: [ internal use only ] * * Asserts that the given entry ends at or before * the specified address; if necessary, * it splits the entry into two. */

 *	it splits the entry into two.
 */
static int
vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t endaddr)
{
	vm_map_entry_t new_entry;
	int bdry_idx;

	if (!map->system_map)
		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
		    "%s: map %p entry %p end 0x%jx", __func__, map, entry,
		    (uintmax_t)endaddr);

	if (endaddr >= entry->end)
		return (KERN_SUCCESS);

	VM_MAP_ASSERT_LOCKED(map);
	KASSERT(entry->start < endaddr && entry->end > endaddr,
	    ("%s: invalid clip of entry %p", __func__, entry));

	bdry_idx = (entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK) >>
	    MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
	if (bdry_idx != 0) {
		if ((endaddr & (pagesizes[bdry_idx] - 1)) != 0)
			return (KERN_INVALID_ARGUMENT);
	}

	new_entry = vm_map_entry_clone(map, entry);

	/*
	 * Split off the back portion.  Insert the new entry AFTER this one,
	 * so that this entry has the specified ending address.
	 */
	new_entry->start = endaddr;
	vm_map_entry_link(map, new_entry);

	return (KERN_SUCCESS);
}

/*
 *	vm_map_submap:		[ kernel use only ]