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 20 #include <sys/cdefs.h> 21 __FBSDID("$FreeBSD$"); 22 23 #include <sys/param.h> 24 #include <sys/systm.h> 25 #include <sys/bio.h> 26 #include <sys/buf.h> 27 #include <sys/conf.h> 28 #include <sys/proc.h> 29 #include <sys/uio.h> 30 31 #include <vm/vm.h> 32 #include <vm/vm_extern.h> 33 34 int 35 physio(struct cdev *dev, struct uio *uio, int ioflag) 36 { 37 struct buf *bp; 38 struct cdevsw *csw; 39 caddr_t sa; 40 u_int iolen; 41 int error, i, mapped; 42 43 /* Keep the process UPAGES from being swapped. XXX: why ? */ 44 PHOLD(curproc); 45 46 bp = getpbuf(NULL); 47 sa = bp->b_data; 48 error = 0; 49 50 /* XXX: sanity check */ 51 if(dev->si_iosize_max < PAGE_SIZE) { 52 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 53 devtoname(dev), dev->si_iosize_max); 54 dev->si_iosize_max = DFLTPHYS; 55 } 56 57 /* 58 * If the driver does not want I/O to be split, that means that we 59 * need to reject any requests that will not fit into one buffer. 60 */ 61 if (dev->si_flags & SI_NOSPLIT && 62 (uio->uio_resid > dev->si_iosize_max || uio->uio_resid > MAXPHYS || 63 uio->uio_iovcnt > 1)) { 64 /* 65 * Tell the user why his I/O was rejected. 66 */ 67 if (uio->uio_resid > dev->si_iosize_max) 68 uprintf("%s: request size=%zd > si_iosize_max=%d; " 69 "cannot split request\n", devtoname(dev), 70 uio->uio_resid, dev->si_iosize_max); 71 if (uio->uio_resid > MAXPHYS) 72 uprintf("%s: request size=%zd > MAXPHYS=%d; " 73 "cannot split request\n", devtoname(dev), 74 uio->uio_resid, MAXPHYS); 75 if (uio->uio_iovcnt > 1) 76 uprintf("%s: request vectors=%d > 1; " 77 "cannot split request\n", devtoname(dev), 78 uio->uio_iovcnt); 79 80 error = EFBIG; 81 goto doerror; 82 } 83 84 for (i = 0; i < uio->uio_iovcnt; i++) { 85 while (uio->uio_iov[i].iov_len) { 86 bp->b_flags = 0; 87 if (uio->uio_rw == UIO_READ) { 88 bp->b_iocmd = BIO_READ; 89 curthread->td_ru.ru_inblock++; 90 } else { 91 bp->b_iocmd = BIO_WRITE; 92 curthread->td_ru.ru_oublock++; 93 } 94 bp->b_iodone = bdone; 95 bp->b_data = uio->uio_iov[i].iov_base; 96 bp->b_bcount = uio->uio_iov[i].iov_len; 97 bp->b_offset = uio->uio_offset; 98 bp->b_iooffset = uio->uio_offset; 99 bp->b_saveaddr = sa; 100 101 /* Don't exceed drivers iosize limit */ 102 if (bp->b_bcount > dev->si_iosize_max) 103 bp->b_bcount = dev->si_iosize_max; 104 105 /* 106 * Make sure the pbuf can map the request 107 * XXX: The pbuf has kvasize = MAXPHYS so a request 108 * XXX: larger than MAXPHYS - PAGE_SIZE must be 109 * XXX: page aligned or it will be fragmented. 110 */ 111 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 112 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 113 /* 114 * This device does not want I/O to be split. 115 */ 116 if (dev->si_flags & SI_NOSPLIT) { 117 uprintf("%s: request ptr %p is not " 118 "on a page boundary; cannot split " 119 "request\n", devtoname(dev), 120 bp->b_data); 121 error = EFBIG; 122 goto doerror; 123 } 124 bp->b_bcount = bp->b_kvasize; 125 if (iolen != 0) 126 bp->b_bcount -= PAGE_SIZE; 127 } 128 bp->b_bufsize = bp->b_bcount; 129 130 bp->b_blkno = btodb(bp->b_offset); 131 132 csw = dev->si_devsw; 133 if (uio->uio_segflg == UIO_USERSPACE) { 134 if (dev->si_flags & SI_UNMAPPED) 135 mapped = 0; 136 else 137 mapped = 1; 138 if (vmapbuf(bp, mapped) < 0) { 139 error = EFAULT; 140 goto doerror; 141 } 142 } 143 144 dev_strategy_csw(dev, csw, bp); 145 if (uio->uio_rw == UIO_READ) 146 bwait(bp, PRIBIO, "physrd"); 147 else 148 bwait(bp, PRIBIO, "physwr"); 149 150 if (uio->uio_segflg == UIO_USERSPACE) 151 vunmapbuf(bp); 152 iolen = bp->b_bcount - bp->b_resid; 153 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR)) 154 goto doerror; /* EOF */ 155 uio->uio_iov[i].iov_len -= iolen; 156 uio->uio_iov[i].iov_base = 157 (char *)uio->uio_iov[i].iov_base + iolen; 158 uio->uio_resid -= iolen; 159 uio->uio_offset += iolen; 160 if( bp->b_ioflags & BIO_ERROR) { 161 error = bp->b_error; 162 goto doerror; 163 } 164 } 165 } 166 doerror: 167 relpbuf(bp, NULL); 168 PRELE(curproc); 169 return (error); 170 } 171