1 /* $OpenBSD: uvm_io.c,v 1.14 2002/10/29 18:30:21 art Exp $ */
2 /* $NetBSD: uvm_io.c,v 1.12 2000/06/27 17:29:23 mrg Exp $ */
3
4 /*
5 *
6 * Copyright (c) 1997 Charles D. Cranor and Washington University.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by Charles D. Cranor and
20 * Washington University.
21 * 4. The name of the author may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 *
35 * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp
36 */
37
38 /*
39 * uvm_io.c: uvm i/o ops
40 */
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/mman.h>
45 #include <sys/proc.h>
46 #include <sys/malloc.h>
47 #include <sys/uio.h>
48
49 #include <uvm/uvm.h>
50
51 /*
52 * functions
53 */
54
55 /*
56 * uvm_io: perform I/O on a map
57 *
58 * => caller must have a reference to "map" so that it doesn't go away
59 * while we are working.
60 */
61
62 int
uvm_io(map,uio)63 uvm_io(map, uio)
64 vm_map_t map;
65 struct uio *uio;
66 {
67 vaddr_t baseva, endva, pageoffset, kva;
68 vsize_t chunksz, togo, sz;
69 vm_map_entry_t dead_entries;
70 int error;
71
72 /*
73 * step 0: sanity checks and set up for copy loop. start with a
74 * large chunk size. if we have trouble finding vm space we will
75 * reduce it.
76 */
77
78 if (uio->uio_resid == 0)
79 return(0);
80 togo = uio->uio_resid;
81
82 baseva = (vaddr_t) uio->uio_offset;
83 endva = baseva + (togo - 1);
84
85 if (endva < baseva) /* wrap around? */
86 return(EIO);
87
88 if (baseva >= VM_MAXUSER_ADDRESS)
89 return(0);
90 if (endva >= VM_MAXUSER_ADDRESS)
91 /* EOF truncate */
92 togo = togo - (endva - VM_MAXUSER_ADDRESS + 1);
93 pageoffset = baseva & PAGE_MASK;
94 baseva = trunc_page(baseva);
95 chunksz = min(round_page(togo + pageoffset), MAXBSIZE);
96 error = 0;
97
98 /*
99 * step 1: main loop... while we've got data to move
100 */
101
102 for (/*null*/; togo > 0 ; pageoffset = 0) {
103
104 /*
105 * step 2: extract mappings from the map into kernel_map
106 */
107
108 error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva,
109 UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG |
110 UVM_EXTRACT_FIXPROT);
111 if (error) {
112
113 /* retry with a smaller chunk... */
114 if (error == ENOMEM && chunksz > PAGE_SIZE) {
115 chunksz = trunc_page(chunksz / 2);
116 if (chunksz < PAGE_SIZE)
117 chunksz = PAGE_SIZE;
118 continue;
119 }
120
121 break;
122 }
123
124 /*
125 * step 3: move a chunk of data
126 */
127
128 sz = chunksz - pageoffset;
129 if (sz > togo)
130 sz = togo;
131 error = uiomove((caddr_t) (kva + pageoffset), sz, uio);
132 togo -= sz;
133 baseva += chunksz;
134
135
136 /*
137 * step 4: unmap the area of kernel memory
138 */
139
140 vm_map_lock(kernel_map);
141 uvm_unmap_remove(kernel_map, kva, kva+chunksz,
142 &dead_entries);
143 vm_map_unlock(kernel_map);
144
145 if (dead_entries != NULL)
146 uvm_unmap_detach(dead_entries, AMAP_REFALL);
147
148 /*
149 * We defer checking the error return from uiomove until
150 * here so that we won't leak memory.
151 */
152 if (error)
153 break;
154 }
155
156 /*
157 * done
158 */
159
160 return (error);
161 }
162