xref: /freebsd/share/man/man9/vm_map_submap.9 (revision 06c3fb27)
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26.Dd July 19, 2003
27.Dt VM_MAP_SUBMAP 9
28.Os
29.Sh NAME
30.Nm vm_map_submap
31.Nd create a subordinate map
32.Sh SYNOPSIS
33.In sys/param.h
34.In vm/vm.h
35.In vm/vm_map.h
36.Ft int
37.Fo vm_map_submap
38.Fa "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "vm_map_t submap"
39.Fc
40.Sh DESCRIPTION
41The
42.Fn vm_map_submap
43function marks the range bounded by
44.Fa start
45and
46.Fa end
47within the map
48.Fa map
49as being handled by a subordinate map
50.Fa sub_map .
51.Pp
52It is generally called by the kernel memory allocator.
53.Sh IMPLEMENTATION NOTES
54This function is for internal use only.
55.Pp
56Both maps must exist.
57The range must have been created with
58.Xr vm_map_find 9
59previously.
60.Pp
61No other operations may have been performed on this range
62before calling this function.
63Only the
64.Fn vm_fault
65operation may be performed within this range after calling
66this function.
67.Pp
68To remove a submapping, one must first remove the range from
69the parent
70.Fa map ,
71and then destroy the
72.Fa sub_map .
73This procedure is not recommended.
74.Sh RETURN VALUES
75The
76.Fn vm_map_submap
77function returns
78.Dv KERN_SUCCESS
79if successful.
80.Pp
81Otherwise, it returns
82.Dv KERN_INVALID_ARGUMENT
83if the caller requested copy-on-write flags,
84or if the range specified for the sub-map was out of range for the parent map,
85or if a
86.Dv NULL
87backing object was specified.
88.Sh SEE ALSO
89.Xr vm_map 9 ,
90.Xr vm_map_find 9
91.Sh AUTHORS
92This manual page was written by
93.An Bruce M Simpson Aq Mt bms@spc.org .
94