xref: /freebsd/share/man/man9/vm_map_submap.9 (revision 911f0260390e18cf85f3dbf2c719b593efdc1e3c)
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26.\" $FreeBSD$
27.\"
28.Dd July 19, 2003
29.Dt VM_MAP_SUBMAP 9
30.Os
31.Sh NAME
32.Nm vm_map_submap
33.Nd create a subordinate map
34.Sh SYNOPSIS
35.In sys/param.h
36.In vm/vm.h
37.In vm/vm_map.h
38.Ft int
39.Fo vm_map_submap
40.Fa "vm_map_t map" "vm_offset_t start" "vm_offset_t end" "vm_map_t submap"
41.Fc
42.Sh DESCRIPTION
43The
44.Fn vm_map_submap
45function marks the range bounded by
46.Fa start
47and
48.Fa end
49within the map
50.Fa map
51as being handled by a subordinate map
52.Fa sub_map .
53.Pp
54It is generally called by the kernel memory allocator.
55.Sh IMPLEMENTATION NOTES
56This function is for internal use only.
57.Pp
58Both maps must exist.
59The range must have been created with
60.Xr vm_map_find 9
61previously.
62.Pp
63No other operations may have been performed on this range
64before calling this function.
65Only the
66.Fn vm_fault
67operation may be performed within this range after calling
68this function.
69.Pp
70To remove a submapping, one must first remove the range from
71the parent
72.Fa map ,
73and then destroy the
74.Fa sub_map .
75This procedure is not recommended.
76.Sh RETURN VALUES
77The
78.Fn vm_map_submap
79function returns
80.Dv KERN_SUCCESS
81if successful.
82.Pp
83Otherwise, it returns
84.Dv KERN_INVALID_ARGUMENT
85if the caller requested copy-on-write flags,
86or if the range specified for the sub-map was out of range for the parent map,
87or if a
88.Dv NULL
89backing object was specified.
90.Sh SEE ALSO
91.Xr vm_map 9 ,
92.Xr vm_map_find 9
93.Sh AUTHORS
94This manual page was written by
95.An Bruce M Simpson Aq Mt bms@spc.org .
96