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#if LP64KERN 94 int64_t done; 95#else 96 int done; 97#endif 98 99 error = 0; 100 flags &= B_READ | B_WRITE; 101 buf_allocated = 0; 102 103 /* 104 * [check user read/write access to the data buffer] 105 * 106 * Check each iov one by one. Note that we know if we're reading or 107 * writing, so we ignore the uio's rw parameter. Also note that if 108 * we're doing a read, that's a *write* to user-space. 109 */ 110 for (i = 0; i < uio->uio_iovcnt; i++) { 111 if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { 112 user_addr_t base; 113 user_size_t len; 114 115 if (uio_getiov(uio, i, &base, &len) || 116 !useracc(base, 117 len, 118 (flags == B_READ) ? B_WRITE : B_READ)) 119 return (EFAULT); 120 } 121 } 122 /* 123 * Make sure we have a buffer, creating one if necessary. 124 */ 125 if (bp == NULL) { 126 bp = buf_alloc((vnode_t)0); 127 buf_allocated = 1; 128 } else 129 orig_bflags = buf_flags(bp); 130 /* 131 * at this point we should have a buffer 132 * that is marked BL_BUSY... we either 133 * acquired it via buf_alloc, or it was 134 * passed into us... if it was passed 135 * in, it needs to already be owned by 136 * the caller (i.e. BL_BUSY is set) 137 */ 138 assert(bp->b_lflags & BL_BUSY); 139 140 /* 141 * [set up the fixed part of the buffer for a transfer] 142 */ 143 bp->b_dev = dev; 144 bp->b_proc = p; 145 146 /* 147 * [mark the buffer busy for physical I/O] 148 * (i.e. set B_PHYS (because it's an I/O to user 149 * memory, and B_RAW, because B_RAW is to be 150 * "Set by physio for raw transfers.", in addition 151 * to the read/write flag.) 152 */ 153 buf_setflags(bp, B_PHYS | B_RAW); 154 155 /* 156 * [while there is data to transfer and no I/O error] 157 * Note that I/O errors are handled with a 'goto' at the bottom 158 * of the 'while' loop. 159 */ 160 while (uio_resid(uio) > 0) { 161 162 if ( (iosize = uio_curriovlen(uio)) > MAXPHYSIO_WIRED) 163 iosize = MAXPHYSIO_WIRED; 164 /* 165 * make sure we're set to issue a fresh I/O 166 * in the right direction 167 */ 168 buf_reset(bp, flags); 169 170 /* [set up the buffer for a maximum-sized transfer] */ 171 buf_setblkno(bp, uio_offset(uio) / blocksize); 172 buf_setcount(bp, iosize); 173 buf_setdataptr(bp, (uintptr_t)CAST_DOWN(caddr_t, uio_curriovbase(uio))); 174 175 /* 176 * [call f_minphys to bound the tranfer size] 177 * and remember the amount of data to transfer, 178 * for later comparison. 179 */ 180 (*f_minphys)(bp); 181 todo = buf_count(bp); 182 183 /* 184 * [lock the part of the user address space involved 185 * in the transfer] 186 */ 187 188 if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { 189 error = vslock(CAST_USER_ADDR_T(buf_dataptr(bp)), 190 (user_size_t)todo); 191 if (error) 192 goto done; 193 } 194 195 /* [call f_strategy to start the transfer] */ 196 (*f_strategy)(bp); 197 198 199 /* [wait for the transfer to complete] */ 200 error = (int)buf_biowait(bp); 201 202 /* 203 * [unlock the part of the address space previously 204 * locked] 205 */ 206 if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) 207 vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)), 208 (user_size_t)todo, 209 (flags & B_READ)); 210 211 /* 212 * [deduct the transfer size from the total number 213 * of data to transfer] 214 */ 215 done = buf_count(bp) - buf_resid(bp); 216 uio_update(uio, done); 217 218 /* 219 * Now, check for an error. 220 * Also, handle weird end-of-disk semantics. 221 */ 222 if (error || done < todo) 223 goto done; 224 } 225 226done: 227 if (buf_allocated) 228 buf_free(bp); 229 else 230 buf_setflags(bp, orig_bflags); 231 232 return (error); 233} 234 235/* 236 * Leffler, et al., says on p. 231: 237 * "The minphys() routine is called by physio() to adjust the 238 * size of each I/O transfer before the latter is passed to 239 * the strategy routine..." 240 * 241 * so, just adjust the buffer's count accounting to MAXPHYS here, 242 * and return the new count; 243 */ 244u_int 245minphys(struct buf *bp) 246{ 247 248 buf_setcount(bp, min(MAXPHYS, buf_count(bp))); 249 return buf_count(bp); 250} 251