1 /* $OpenBSD: uvm_io.c,v 1.13 2001/12/19 08:58:07 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 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 (void)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