1 /* 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 * 19 * $FreeBSD: src/sys/kern/kern_physio.c,v 1.46.2.4 2003/11/14 09:51:47 simokawa Exp $ 20 * $DragonFly: src/sys/kern/kern_physio.c,v 1.12 2005/08/04 21:08:35 hmp Exp $ 21 */ 22 23 #include <sys/param.h> 24 #include <sys/systm.h> 25 #include <sys/buf.h> 26 #include <sys/conf.h> 27 #include <sys/proc.h> 28 #include <sys/uio.h> 29 #include <sys/device.h> 30 #include <sys/thread2.h> 31 32 #include <vm/vm.h> 33 #include <vm/vm_extern.h> 34 35 static void 36 physwakeup(struct buf *bp) 37 { 38 wakeup((caddr_t) bp); 39 } 40 41 int 42 physio(dev_t dev, struct uio *uio, int ioflag) 43 { 44 int i; 45 int error; 46 int chk_blockno; 47 caddr_t sa; 48 off_t blockno; 49 u_int iolen; 50 struct buf *bp; 51 52 /* 53 * NOTE: we no longer have to PHOLD() the process, because the 54 * kernel stack / uarea cannot be swapped, and when it can be in 55 * the future it will only happen if the process is sleeping on 56 * a particular address. 57 */ 58 bp = getpbuf(NULL); 59 sa = bp->b_data; 60 error = 0; 61 62 /* XXX: sanity check */ 63 if(dev->si_iosize_max < PAGE_SIZE) { 64 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 65 devtoname(dev), dev->si_iosize_max); 66 dev->si_iosize_max = DFLTPHYS; 67 } 68 69 /* Don't check block number overflow for D_MEM */ 70 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM) 71 chk_blockno = 0; 72 else 73 chk_blockno = 1; 74 75 for (i = 0; i < uio->uio_iovcnt; i++) { 76 while (uio->uio_iov[i].iov_len) { 77 if (uio->uio_rw == UIO_READ) 78 bp->b_flags = B_PHYS | B_READ; 79 else 80 bp->b_flags = B_PHYS | B_WRITE; 81 bp->b_dev = dev; 82 bp->b_iodone = physwakeup; 83 bp->b_data = uio->uio_iov[i].iov_base; 84 bp->b_bcount = uio->uio_iov[i].iov_len; 85 bp->b_offset = uio->uio_offset; 86 bp->b_saveaddr = sa; 87 88 /* Don't exceed drivers iosize limit */ 89 if (bp->b_bcount > dev->si_iosize_max) 90 bp->b_bcount = dev->si_iosize_max; 91 92 /* 93 * Make sure the pbuf can map the request 94 * XXX: The pbuf has kvasize = MAXPHYS so a request 95 * XXX: larger than MAXPHYS - PAGE_SIZE must be 96 * XXX: page aligned or it will be fragmented. 97 */ 98 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 99 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 100 bp->b_bcount = bp->b_kvasize; 101 if (iolen != 0) 102 bp->b_bcount -= PAGE_SIZE; 103 } 104 bp->b_bufsize = bp->b_bcount; 105 106 blockno = bp->b_offset >> DEV_BSHIFT; 107 if (chk_blockno && (daddr_t)blockno != blockno) { 108 error = EINVAL; /* blockno overflow */ 109 goto doerror; 110 } 111 bp->b_blkno = blockno; 112 113 if (uio->uio_segflg == UIO_USERSPACE) 114 if (vmapbuf(bp) < 0) { 115 error = EFAULT; 116 goto doerror; 117 } 118 119 BUF_STRATEGY(bp, 0); 120 crit_enter(); 121 while ((bp->b_flags & B_DONE) == 0) 122 tsleep((caddr_t)bp, 0, "physstr", 0); 123 crit_exit(); 124 125 if (uio->uio_segflg == UIO_USERSPACE) 126 vunmapbuf(bp); 127 iolen = bp->b_bcount - bp->b_resid; 128 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 129 goto doerror; /* EOF */ 130 uio->uio_iov[i].iov_len -= iolen; 131 uio->uio_iov[i].iov_base += iolen; 132 uio->uio_resid -= iolen; 133 uio->uio_offset += iolen; 134 if( bp->b_flags & B_ERROR) { 135 error = bp->b_error; 136 goto doerror; 137 } 138 } 139 } 140 doerror: 141 bp->b_data = sa; 142 relpbuf(bp, NULL); 143 return (error); 144 } 145