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.\" $FreeBSD: src/share/man/man9/vm_map_submap.9,v 1.4.22.1.6.1 2010/12/21 17:09:25 kensmith Exp $
.\"
.Dd July 19, 2003
.Dt VM_MAP_SUBMAP 9
.Os
.Sh NAME
.Nm vm_map_submap
.Nd create a subordinate map
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/vm_map.h
.Ft int
.Fo vm_map_submap
.Fa "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "vm_map_t submap"
.Fc
.Sh DESCRIPTION
The
.Fn vm_map_submap
function marks the range bounded by
.Fa start
and
.Fa end
within the map
.Fa map
as being handled by a subordinate map
.Fa sub_map .
.Pp
It is generally called by the kernel memory allocator.
.Sh IMPLEMENTATION NOTES
This function is for internal use only.
.Pp
Both maps must exist.
The range must have been created with
.Xr vm_map_find 9
previously.
.Pp
No other operations may have been performed on this range
before calling this function.
Only the
.Fn vm_fault
operation may be performed within this range after calling
this function.
.Pp
To remove a submapping, one must first remove the range from
the parent
.Fa map ,
and then destroy the
.Fa sub_map .
This procedure is not recommended.
.Sh RETURN VALUES
The
.Fn vm_map_submap
function returns
.Dv KERN_SUCCESS
if successful.
.Pp
Otherwise, it returns
.Dv KERN_INVALID_ARGUMENT
if the caller requested copy-on-write flags,
or if the range specified for the sub-map was out of range for the parent map,
or if a
.Dv NULL
backing object was specified.
.Sh SEE ALSO
.Xr vm_map 9 ,
.Xr vm_map_find 9
.Sh AUTHORS
This manual page was written by
.An Bruce M Simpson Aq bms@spc.org .