1 /* $NetBSD: uvm_io.c,v 1.8 1999/03/25 18:48:51 mrg Exp $ */ 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. 33 * 34 * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp 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 65 int 66 uvm_io(map, uio) 67 vm_map_t map; 68 struct uio *uio; 69 { 70 vaddr_t baseva, endva, pageoffset, kva; 71 vsize_t chunksz, togo, sz; 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 85 baseva = (vaddr_t) uio->uio_offset; 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 */ 110 111 error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva, 112 UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | 113 UVM_EXTRACT_FIXPROT); 114 if (error) { 115 116 /* 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); 146 (void)uvm_unmap_remove(kernel_map, kva, kva+chunksz, 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 */ 157 158 return (error); 159 } 160