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/param.h> 21#include <sys/systm.h> 22#include <sys/bio.h> 23#include <sys/buf.h> 24#include <sys/conf.h> 25#include <sys/malloc.h> 26#include <sys/proc.h> 27#include <sys/racct.h> 28#include <sys/rwlock.h> 29#include <sys/uio.h> 30#include <geom/geom.h> 31 32#include <vm/vm.h> 33#include <vm/vm_object.h> 34#include <vm/vm_page.h> 35#include <vm/vm_pager.h> 36#include <vm/vm_extern.h> 37#include <vm/vm_map.h> 38 39int 40physio(struct cdev *dev, struct uio *uio, int ioflag) 41{ 42 struct cdevsw *csw; 43 struct buf *pbuf; 44 struct bio *bp; 45 struct vm_page **pages; 46 char *base, *sa; 47 u_int iolen, poff; 48 int error, i, npages, maxpages; 49 vm_prot_t prot; 50 51 csw = dev->si_devsw; 52 npages = 0; 53 sa = NULL; 54 /* check if character device is being destroyed */ 55 if (csw == NULL) 56 return (ENXIO); 57 58 /* XXX: sanity check */ 59 if (dev->si_iosize_max < PAGE_SIZE) { 60 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 61 devtoname(dev), dev->si_iosize_max); 62 dev->si_iosize_max = DFLTPHYS; 63 } 64 65 /* 66 * If the driver does not want I/O to be split, that means that we 67 * need to reject any requests that will not fit into one buffer. 68 */ 69 if (dev->si_flags & SI_NOSPLIT && 70 (uio->uio_resid > dev->si_iosize_max || uio->uio_resid > maxphys || 71 uio->uio_iovcnt > 1)) { 72 /* 73 * Tell the user why his I/O was rejected. 74 */ 75 if (uio->uio_resid > dev->si_iosize_max) 76 uprintf("%s: request size=%zd > si_iosize_max=%d; " 77 "cannot split request\n", devtoname(dev), 78 uio->uio_resid, dev->si_iosize_max); 79 if (uio->uio_resid > maxphys) 80 uprintf("%s: request size=%zd > maxphys=%lu; " 81 "cannot split request\n", devtoname(dev), 82 uio->uio_resid, maxphys); 83 if (uio->uio_iovcnt > 1) 84 uprintf("%s: request vectors=%d > 1; " 85 "cannot split request\n", devtoname(dev), 86 uio->uio_iovcnt); 87 return (EFBIG); 88 } 89 90 /* 91 * Keep the process UPAGES from being swapped. Processes swapped 92 * out while holding pbufs, used by swapper, may lead to deadlock. 93 */ 94 PHOLD(curproc); 95 96 bp = g_alloc_bio(); 97 if (uio->uio_segflg != UIO_USERSPACE) { 98 pbuf = NULL; 99 pages = NULL; 100 } else if ((dev->si_flags & SI_UNMAPPED) && unmapped_buf_allowed) { 101 pbuf = NULL; 102 maxpages = btoc(MIN(uio->uio_resid, maxphys)) + 1; 103 pages = malloc(sizeof(*pages) * maxpages, M_DEVBUF, M_WAITOK); 104 } else { 105 pbuf = uma_zalloc(pbuf_zone, M_WAITOK); 106 MPASS((pbuf->b_flags & B_MAXPHYS) != 0); 107 sa = pbuf->b_data; 108 maxpages = PBUF_PAGES; 109 pages = pbuf->b_pages; 110 } 111 prot = VM_PROT_READ; 112 if (uio->uio_rw == UIO_READ) 113 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 114 error = 0; 115 for (i = 0; i < uio->uio_iovcnt; i++) { 116#ifdef RACCT 117 if (racct_enable) { 118 PROC_LOCK(curproc); 119 switch (uio->uio_rw) { 120 case UIO_READ: 121 racct_add_force(curproc, RACCT_READBPS, 122 uio->uio_iov[i].iov_len); 123 racct_add_force(curproc, RACCT_READIOPS, 1); 124 break; 125 case UIO_WRITE: 126 racct_add_force(curproc, RACCT_WRITEBPS, 127 uio->uio_iov[i].iov_len); 128 racct_add_force(curproc, RACCT_WRITEIOPS, 1); 129 break; 130 } 131 PROC_UNLOCK(curproc); 132 } 133#endif /* RACCT */ 134 135 while (uio->uio_iov[i].iov_len) { 136 g_reset_bio(bp); 137 switch (uio->uio_rw) { 138 case UIO_READ: 139 bp->bio_cmd = BIO_READ; 140 curthread->td_ru.ru_inblock++; 141 break; 142 case UIO_WRITE: 143 bp->bio_cmd = BIO_WRITE; 144 curthread->td_ru.ru_oublock++; 145 break; 146 } 147 bp->bio_offset = uio->uio_offset; 148 base = uio->uio_iov[i].iov_base; 149 bp->bio_length = uio->uio_iov[i].iov_len; 150 if (bp->bio_length > dev->si_iosize_max) 151 bp->bio_length = dev->si_iosize_max; 152 if (bp->bio_length > maxphys) 153 bp->bio_length = maxphys; 154 bp->bio_bcount = bp->bio_length; 155 bp->bio_dev = dev; 156 157 if (pages) { 158 if ((npages = vm_fault_quick_hold_pages( 159 &curproc->p_vmspace->vm_map, 160 (vm_offset_t)base, bp->bio_length, 161 prot, pages, maxpages)) < 0) { 162 error = EFAULT; 163 goto doerror; 164 } 165 poff = (vm_offset_t)base & PAGE_MASK; 166 if (pbuf && sa) { 167 pmap_qenter((vm_offset_t)sa, 168 pages, npages); 169 bp->bio_data = sa + poff; 170 } else { 171 bp->bio_ma = pages; 172 bp->bio_ma_n = npages; 173 bp->bio_ma_offset = poff; 174 bp->bio_data = unmapped_buf; 175 bp->bio_flags |= BIO_UNMAPPED; 176 } 177 } else 178 bp->bio_data = base; 179 180 csw->d_strategy(bp); 181 if (uio->uio_rw == UIO_READ) 182 biowait(bp, "physrd"); 183 else 184 biowait(bp, "physwr"); 185 186 if (pages) { 187 if (pbuf) 188 pmap_qremove((vm_offset_t)sa, npages); 189 vm_page_unhold_pages(pages, npages); 190 } 191 192 iolen = bp->bio_length - bp->bio_resid; 193 if (iolen == 0 && !(bp->bio_flags & BIO_ERROR)) 194 goto doerror; /* EOF */ 195 uio->uio_iov[i].iov_len -= iolen; 196 uio->uio_iov[i].iov_base = 197 (char *)uio->uio_iov[i].iov_base + iolen; 198 uio->uio_resid -= iolen; 199 uio->uio_offset += iolen; 200 if (bp->bio_flags & BIO_ERROR) { 201 error = bp->bio_error; 202 goto doerror; 203 } 204 } 205 } 206doerror: 207 if (pbuf) 208 uma_zfree(pbuf_zone, pbuf); 209 else if (pages) 210 free(pages, M_DEVBUF); 211 g_destroy_bio(bp); 212 PRELE(curproc); 213 return (error); 214} 215