1.\" 2.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd May 10, 2008 29.Dt VM_MAP_FIND 9 30.Os 31.Sh NAME 32.Nm vm_map_find 33.Nd find a free region within a map, and optionally map a vm_object 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_find 40.Fa "vm_map_t map" "vm_object_t object" "vm_ooffset_t offset" 41.Fa "vm_offset_t *addr" "vm_size_t length" "int find_space" 42.Fa "vm_prot_t prot" "vm_prot_t max" "int cow" 43.Fc 44.Sh DESCRIPTION 45The 46.Fn vm_map_find 47function attempts to find a free region in the target 48.Fa map , 49with the given 50.Fa length , 51and will also optionally create a mapping of 52.Fa object . 53.Pp 54The arguments 55.Fa offset , 56.Fa prot , 57.Fa max , 58and 59.Fa cow 60are passed unchanged to 61.Xr vm_map_insert 9 62when creating the mapping, if and only if a free region is found. 63.Pp 64If 65.Fa object 66is 67.Pf non- Dv NULL , 68the reference count on the object must be incremented 69by the caller before calling this function to account for the new entry. 70.Pp 71If 72.Fa find_space 73is either 74.Dv VMFS_ALIGNED_SPACE 75or 76.Dv VMFS_ANY_SPACE , 77the function will call 78.Xr vm_map_findspace 9 79to discover a free region. 80Moreover, if 81.Fa find_space 82is 83.Dv VMFS_ALIGNED_SPACE , 84the address of the free region will be optimized for the use of superpages. 85Otherwise, if 86.Fa find_space 87is 88.Dv VMFS_NO_SPACE , 89.Xr vm_map_insert 9 90is called with the given address, 91.Fa addr . 92.Sh IMPLEMENTATION NOTES 93This function acquires a lock on 94.Fa map 95by calling 96.Xr vm_map_lock 9 , 97and holds it until the function returns. 98.Pp 99The search for a free region is defined to be first-fit, from the address 100.Fa addr 101onwards. 102.Sh RETURN VALUES 103The 104.Fn vm_map_find 105function returns 106.Dv KERN_SUCCESS 107if the mapping was successfully created. 108If space could not be found or 109.Fa find_space 110was 111.Dv VMFS_NO_SPACE 112and the given address, 113.Fa addr , 114was already mapped, 115.Dv KERN_NO_SPACE 116will be returned. 117If the discovered range turned out to be bogus, 118.Dv KERN_INVALID_ADDRESS 119will be returned. 120.Sh SEE ALSO 121.Xr vm_map 9 , 122.Xr vm_map_findspace 9 , 123.Xr vm_map_insert 9 , 124.Xr vm_map_lock 9 125.Sh AUTHORS 126This manual page was written by 127.An Bruce M Simpson Aq bms@spc.org . 128