Annotation of src/sys/uvm/uvm_io.c, Revision 1.10
1.10 ! pk 1: /* $NetBSD: uvm_io.c,v 1.9 2000/06/02 11:47:53 pk Exp $ */
1.1 mrg 2:
3: /*
4: *
5: * Copyright (c) 1997 Charles D. Cranor and Washington University.
6: * All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by Charles D. Cranor and
19: * Washington University.
20: * 4. The name of the author may not be used to endorse or promote products
21: * derived from this software without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.3 mrg 33: *
34: * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp
1.1 mrg 35: */
36:
37: /*
38: * uvm_io.c: uvm i/o ops
39: */
40:
41: #include <sys/param.h>
42: #include <sys/systm.h>
43: #include <sys/mman.h>
44: #include <sys/proc.h>
45: #include <sys/malloc.h>
46: #include <sys/uio.h>
47:
48: #include <vm/vm.h>
49: #include <vm/vm_page.h>
50: #include <vm/vm_kern.h>
51:
52: #include <uvm/uvm.h>
53:
54: /*
55: * functions
56: */
57:
58: /*
59: * uvm_io: perform I/O on a map
60: *
61: * => caller must have a reference to "map" so that it doesn't go away
62: * while we are working.
63: */
64:
1.4 mrg 65: int
66: uvm_io(map, uio)
67: vm_map_t map;
68: struct uio *uio;
1.1 mrg 69: {
1.6 eeh 70: vaddr_t baseva, endva, pageoffset, kva;
71: vsize_t chunksz, togo, sz;
1.4 mrg 72: vm_map_entry_t dead_entries;
73: int error;
74:
75: /*
76: * step 0: sanity checks and set up for copy loop. start with a
77: * large chunk size. if we have trouble finding vm space we will
78: * reduce it.
79: */
80:
81: if (uio->uio_resid == 0)
82: return(0);
83: togo = uio->uio_resid;
84:
1.6 eeh 85: baseva = (vaddr_t) uio->uio_offset;
1.4 mrg 86: endva = baseva + (togo - 1);
87:
88: if (endva < baseva) /* wrap around? */
89: return(EIO);
90:
91: if (baseva >= VM_MAXUSER_ADDRESS)
92: return(0);
93: if (endva >= VM_MAXUSER_ADDRESS)
94: /* EOF truncate */
95: togo = togo - (endva - VM_MAXUSER_ADDRESS + 1);
96: pageoffset = baseva & PAGE_MASK;
97: baseva = trunc_page(baseva);
98: chunksz = min(round_page(togo + pageoffset), MAXBSIZE);
99: error = 0;
100:
101: /*
102: * step 1: main loop... while we've got data to move
103: */
104:
105: for (/*null*/; togo > 0 ; pageoffset = 0) {
106:
107: /*
108: * step 2: extract mappings from the map into kernel_map
109: */
1.1 mrg 110:
1.4 mrg 111: error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva,
1.1 mrg 112: UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG |
113: UVM_EXTRACT_FIXPROT);
1.4 mrg 114: if (error) {
1.1 mrg 115:
1.4 mrg 116: /* retry with a smaller chunk... */
117: if (error == ENOMEM && chunksz > PAGE_SIZE) {
118: chunksz = trunc_page(chunksz / 2);
119: if (chunksz < PAGE_SIZE)
120: chunksz = PAGE_SIZE;
121: continue;
122: }
123:
124: break;
125: }
126:
127: /*
128: * step 3: move a chunk of data
129: */
130:
131: sz = chunksz - pageoffset;
132: if (sz > togo)
133: sz = togo;
134: error = uiomove((caddr_t) (kva + pageoffset), sz, uio);
135: if (error)
136: break;
137: togo -= sz;
138: baseva += chunksz;
139:
140:
141: /*
142: * step 4: unmap the area of kernel memory
143: */
144:
145: vm_map_lock(kernel_map);
1.7 chuck 146: (void)uvm_unmap_remove(kernel_map, kva, kva+chunksz,
1.4 mrg 147: &dead_entries);
148: vm_map_unlock(kernel_map);
149:
150: if (dead_entries != NULL)
151: uvm_unmap_detach(dead_entries, AMAP_REFALL);
152: }
153:
154: /*
155: * done
156: */
1.1 mrg 157:
1.4 mrg 158: return (error);
1.1 mrg 159: }
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