/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This 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 OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_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.h> #include <sys/conf.h> #include <sys/proc.h> int physio(strategy, bp, dev, flags, minphys, uio, blocksize) void (*strategy)(); struct buf *bp; dev_t dev; int flags; u_int (*minphys)(); struct uio *uio; int blocksize; { struct iovec *iovp; struct proc *p = current_proc(); int error, done, i, nobuf, s, todo; error = 0; flags &= B_READ | B_WRITE; /* * [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->uio_segflg != UIO_SYSSPACE) { if (!useracc(uio->uio_iov[i].iov_base, uio->uio_iov[i].iov_len, (flags == B_READ) ? B_WRITE : B_READ)) return (EFAULT); } } /* Make sure we have a buffer, creating one if necessary. */ if (nobuf = (bp == NULL)) { // bp = getphysbuf(); panic("physio: null buf pointer\n"); } /* [raise the processor priority level to splbio;] */ s = splbio(); /* [while the buffer is marked busy] */ while (bp->b_flags & B_BUSY) { /* [mark the buffer wanted] */ bp->b_flags |= B_WANTED; /* [wait until the buffer is available] */ tsleep((caddr_t)bp, PRIBIO+1, "physbuf", 0); } /* Mark it busy, so nobody else will use it. */ bp->b_flags |= B_BUSY; /* [lower the priority level] */ splx(s); /* [set up the fixed part of the buffer for a transfer] */ bp->b_dev = dev; bp->b_error = 0; bp->b_proc = p; /* * [while there are 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. */ for (i = 0; i < uio->uio_iovcnt; i++) { iovp = &uio->uio_iov[i]; while (iovp->iov_len > 0) { /* * [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 "busy" and read/write flag.) */ s = splbio(); bp->b_flags = B_BUSY | B_PHYS | B_RAW | flags; splx(s); /* [set up the buffer for a maximum-sized transfer] */ bp->b_blkno = uio->uio_offset / blocksize; bp->b_bcount = iovp->iov_len; bp->b_data = iovp->iov_base; /* * [call minphys to bound the tranfer size] * and remember the amount of data to transfer, * for later comparison. */ (*minphys)(bp); todo = bp->b_bcount; /* * [lock the part of the user address space involved * in the transfer] * Beware vmapbuf(); it clobbers b_data and * saves it in b_saveaddr. However, vunmapbuf() * restores it. */ if(uio->uio_segflg != UIO_SYSSPACE) vslock(bp->b_data, todo); #if 0 vmapbuf(bp, todo); #endif /* 0 */ /* [call strategy to start the transfer] */ (*strategy)(bp); /* * Note that the raise/wait/lower/get error * steps below would be done by biowait(), but * we want to unlock the address space before * we lower the priority. * * [raise the priority level to splbio] */ s = splbio(); /* [wait for the transfer to complete] */ while ((bp->b_flags & B_DONE) == 0) tsleep((caddr_t) bp, PRIBIO + 1, "physio", 0); /* * [unlock the part of the address space previously * locked] */ #if 0 vunmapbuf(bp, todo); #endif /* 0 */ if(uio->uio_segflg != UIO_SYSSPACE) vsunlock(bp->b_data, todo); /* remember error value (save a splbio/splx pair) */ if (bp->b_flags & B_ERROR) error = (bp->b_error ? bp->b_error : EIO); /* [lower the priority level] */ splx(s); /* * [deduct the transfer size from the total number * of data to transfer] */ done = bp->b_bcount - bp->b_resid; iovp->iov_len -= done; iovp->iov_base += done; uio->uio_offset += done; uio->uio_resid -= done; /* * Now, check for an error. * Also, handle weird end-of-disk semantics. */ if (error || done < todo) goto done; } } done: /* * [clean up the state of the buffer] * Remember if somebody wants it, so we can wake them up below. * Also, if we had to steal it, give it back. */ s = splbio(); bp->b_flags &= ~(B_BUSY | B_PHYS | B_RAW); #if 0 if (nobuf) putphysbuf(bp); else #endif /* 0 */ { /* * [if another process is waiting for the raw I/O buffer, * wake up processes waiting to do physical I/O; */ if (bp->b_flags & B_WANTED) { bp->b_flags &= ~B_WANTED; wakeup(bp); } } splx(s); 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(bp) struct buf *bp; { bp->b_bcount = min(MAXPHYS, bp->b_bcount); return bp->b_bcount; } /* * Do a read on a device for a user process. */ rawread(dev, uio) dev_t dev; struct uio *uio; { return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, dev, B_READ, minphys, uio, DEV_BSIZE)); } /* * Do a write on a device for a user process. */ rawwrite(dev, uio) dev_t dev; struct uio *uio; { return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, dev, B_WRITE, minphys, uio, DEV_BSIZE)); }