/* * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /*- * Copyright (c) 1982, 1986, 1990, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)kern_physio.c 8.1 (Berkeley) 6/10/93 */ /* * HISTORY * 27-July-97 Umesh Vaishampayan (umeshv@apple.com) * Allow physio() to kernel space. */ #include <sys/param.h> #include <sys/systm.h> #include <sys/buf_internal.h> #include <sys/conf.h> #include <sys/proc_internal.h> #include <sys/uio_internal.h> #include <kern/assert.h> int physio( void (*f_strategy)(buf_t), buf_t bp, dev_t dev, int flags, u_int (*f_minphys)(buf_t), struct uio *uio, int blocksize) { struct proc *p = current_proc(); int error, i, buf_allocated, todo; size_t iosize; int orig_bflags = 0; int64_t done; error = 0; flags &= B_READ | B_WRITE; buf_allocated = 0; /* * [check user read/write access to the data buffer] * * Check each iov one by one. Note that we know if we're reading or * writing, so we ignore the uio's rw parameter. Also note that if * we're doing a read, that's a *write* to user-space. */ for (i = 0; i < uio->uio_iovcnt; i++) { if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { user_addr_t base; user_size_t len; if (uio_getiov(uio, i, &base, &len) || !useracc(base, len, (flags == B_READ) ? B_WRITE : B_READ)) { return EFAULT; } } } /* * Make sure we have a buffer, creating one if necessary. */ if (bp == NULL) { bp = buf_alloc((vnode_t)0); buf_allocated = 1; } else { orig_bflags = buf_flags(bp); } /* * at this point we should have a buffer * that is marked BL_BUSY... we either * acquired it via buf_alloc, or it was * passed into us... if it was passed * in, it needs to already be owned by * the caller (i.e. BL_BUSY is set) */ assert(bp->b_lflags & BL_BUSY); /* * [set up the fixed part of the buffer for a transfer] */ bp->b_dev = dev; bp->b_proc = p; /* * [mark the buffer busy for physical I/O] * (i.e. set B_PHYS (because it's an I/O to user * memory, and B_RAW, because B_RAW is to be * "Set by physio for raw transfers.", in addition * to the read/write flag.) */ buf_setflags(bp, B_PHYS | B_RAW); /* * [while there is data to transfer and no I/O error] * Note that I/O errors are handled with a 'goto' at the bottom * of the 'while' loop. */ while (uio_resid(uio) > 0) { iosize = uio_curriovlen(uio); if (iosize > MAXPHYSIO_WIRED) { iosize = MAXPHYSIO_WIRED; } /* * make sure we're set to issue a fresh I/O * in the right direction */ buf_reset(bp, flags); /* [set up the buffer for a maximum-sized transfer] */ buf_setblkno(bp, uio_offset(uio) / blocksize); assert(iosize <= UINT32_MAX); buf_setcount(bp, (uint32_t)iosize); buf_setdataptr(bp, (uintptr_t)CAST_DOWN(caddr_t, uio_curriovbase(uio))); /* * [call f_minphys to bound the tranfer size] * and remember the amount of data to transfer, * for later comparison. */ (*f_minphys)(bp); todo = buf_count(bp); /* * [lock the part of the user address space involved * in the transfer] */ if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { error = vslock(CAST_USER_ADDR_T(buf_dataptr(bp)), (user_size_t)todo); if (error) { goto finished; } } /* [call f_strategy to start the transfer] */ (*f_strategy)(bp); /* [wait for the transfer to complete] */ error = (int)buf_biowait(bp); /* * [unlock the part of the address space previously * locked] */ if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) { vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)), (user_size_t)todo, (flags & B_READ)); } /* * [deduct the transfer size from the total number * of data to transfer] */ done = buf_count(bp) - buf_resid(bp); assert(0 <= done && done <= UINT32_MAX); uio_update(uio, (user_size_t)done); /* * Now, check for an error. * Also, handle weird end-of-disk semantics. */ if (error || done < todo) { goto finished; } } finished: if (buf_allocated) { buf_free(bp); } else { buf_setflags(bp, orig_bflags); } return error; } /* * Leffler, et al., says on p. 231: * "The minphys() routine is called by physio() to adjust the * size of each I/O transfer before the latter is passed to * the strategy routine..." * * so, just adjust the buffer's count accounting to MAXPHYS here, * and return the new count; */ u_int minphys(struct buf *bp) { buf_setcount(bp, min(MAXPHYS, buf_count(bp))); return buf_count(bp); }