1/* 2 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/*- 29 * Copyright (c) 1982, 1986, 1990, 1993 30 * The Regents of the University of California. All rights reserved. 31 * (c) UNIX System Laboratories, Inc. 32 * All or some portions of this file are derived from material licensed 33 * to the University of California by American Telephone and Telegraph 34 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 35 * the permission of UNIX System Laboratories, Inc. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. All advertising materials mentioning features or use of this software 46 * must display the following acknowledgement: 47 * This product includes software developed by the University of 48 * California, Berkeley and its contributors. 49 * 4. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * from: @(#)kern_physio.c 8.1 (Berkeley) 6/10/93 66 */ 67/* 68 * HISTORY 69 * 27-July-97 Umesh Vaishampayan (umeshv@apple.com) 70 * Allow physio() to kernel space. 71 */ 72 73#include <sys/param.h> 74#include <sys/systm.h> 75#include <sys/buf_internal.h> 76#include <sys/conf.h> 77#include <sys/proc_internal.h> 78#include <sys/uio_internal.h> 79#include <kern/assert.h> 80 81int 82physio( void (*f_strategy)(buf_t), 83 buf_t bp, 84 dev_t dev, 85 int flags, 86 u_int (*f_minphys)(buf_t), 87 struct uio *uio, 88 int blocksize) 89{ 90 struct proc *p = current_proc(); 91 int error, i, buf_allocated, todo, iosize; 92 int orig_bflags = 0; 93 int64_t done; 94 95 error = 0; 96 flags &= B_READ | B_WRITE; 97 buf_allocated = 0; 98 99 /* 100 * [check user read/write access to the data buffer] 101 * 102 * Check each iov one by one. Note that we know if we're reading or 103 * writing, so we ignore the uio's rw parameter. Also note that if 104 * we're doing a read, that's a *write* to user-space. 105 */ 106 for (i = 0; i < uio->uio_iovcnt; i++) { 107 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { 108 user_addr_t base; 109 user_size_t len; 110 111 if (uio_getiov(uio, i, &base, &len) || 112 !useracc(base, 113 len, 114 (flags == B_READ) ? B_WRITE : B_READ)) 115 return (EFAULT); 116 } 117 } 118 /* 119 * Make sure we have a buffer, creating one if necessary. 120 */ 121 if (bp == NULL) { 122 bp = buf_alloc((vnode_t)0); 123 buf_allocated = 1; 124 } else 125 orig_bflags = buf_flags(bp); 126 /* 127 * at this point we should have a buffer 128 * that is marked BL_BUSY... we either 129 * acquired it via buf_alloc, or it was 130 * passed into us... if it was passed 131 * in, it needs to already be owned by 132 * the caller (i.e. BL_BUSY is set) 133 */ 134 assert(bp->b_lflags & BL_BUSY); 135 136 /* 137 * [set up the fixed part of the buffer for a transfer] 138 */ 139 bp->b_dev = dev; 140 bp->b_proc = p; 141 142 /* 143 * [mark the buffer busy for physical I/O] 144 * (i.e. set B_PHYS (because it's an I/O to user 145 * memory, and B_RAW, because B_RAW is to be 146 * "Set by physio for raw transfers.", in addition 147 * to the read/write flag.) 148 */ 149 buf_setflags(bp, B_PHYS | B_RAW); 150 151 /* 152 * [while there is data to transfer and no I/O error] 153 * Note that I/O errors are handled with a 'goto' at the bottom 154 * of the 'while' loop. 155 */ 156 while (uio_resid(uio) > 0) { 157 158 if ( (iosize = uio_curriovlen(uio)) > MAXPHYSIO_WIRED) 159 iosize = MAXPHYSIO_WIRED; 160 /* 161 * make sure we're set to issue a fresh I/O 162 * in the right direction 163 */ 164 buf_reset(bp, flags); 165 166 /* [set up the buffer for a maximum-sized transfer] */ 167 buf_setblkno(bp, uio_offset(uio) / blocksize); 168 buf_setcount(bp, iosize); 169 buf_setdataptr(bp, (uintptr_t)CAST_DOWN(caddr_t, uio_curriovbase(uio))); 170 171 /* 172 * [call f_minphys to bound the tranfer size] 173 * and remember the amount of data to transfer, 174 * for later comparison. 175 */ 176 (*f_minphys)(bp); 177 todo = buf_count(bp); 178 179 /* 180 * [lock the part of the user address space involved 181 * in the transfer] 182 */ 183 184 if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { 185 error = vslock(CAST_USER_ADDR_T(buf_dataptr(bp)), 186 (user_size_t)todo); 187 if (error) 188 goto done; 189 } 190 191 /* [call f_strategy to start the transfer] */ 192 (*f_strategy)(bp); 193 194 195 /* [wait for the transfer to complete] */ 196 error = (int)buf_biowait(bp); 197 198 /* 199 * [unlock the part of the address space previously 200 * locked] 201 */ 202 if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) 203 vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)), 204 (user_size_t)todo, 205 (flags & B_READ)); 206 207 /* 208 * [deduct the transfer size from the total number 209 * of data to transfer] 210 */ 211 done = buf_count(bp) - buf_resid(bp); 212 uio_update(uio, done); 213 214 /* 215 * Now, check for an error. 216 * Also, handle weird end-of-disk semantics. 217 */ 218 if (error || done < todo) 219 goto done; 220 } 221 222done: 223 if (buf_allocated) 224 buf_free(bp); 225 else 226 buf_setflags(bp, orig_bflags); 227 228 return (error); 229} 230 231/* 232 * Leffler, et al., says on p. 231: 233 * "The minphys() routine is called by physio() to adjust the 234 * size of each I/O transfer before the latter is passed to 235 * the strategy routine..." 236 * 237 * so, just adjust the buffer's count accounting to MAXPHYS here, 238 * and return the new count; 239 */ 240u_int 241minphys(struct buf *bp) 242{ 243 244 buf_setcount(bp, min(MAXPHYS, buf_count(bp))); 245 return buf_count(bp); 246} 247